Guest Essay by Kip Hansen — 7 February 2023
Hark! I hear birds singing. And I hear a study reaching out for attention.
The new study is about stickers that people apply to their windows hoping that they will prevent birds from flying into the window because they think that there is a clear route to some place of safety.
“A thump on the window, if you’re around to hear it. A dead songbird below. Many people seek to prevent this sorrowful scenario by warning birds away with decals or film applied to windows of homes and office buildings.” [ source ]
A 2014 study found:
“Building collisions, and particularly collisions with windows, are a major anthropogenic threat to birds, with rough estimates of between 100 million and 1 billion birds killed annually in the United States. However, no current U.S. estimates are based on systematic analysis of multiple data sources. We reviewed the published literature and acquired unpublished datasets to systematically quantify bird–building collision mortality and species-specific vulnerability. Based on 23 studies, we estimate that between 365 and 988 million birds (median = 599 million) are killed annually by building collisions in the U.S., with roughly 56% of mortality at low-rises, 44% at residences, and <1% at high-rises.”
National Audubon encourages homeowners to protect birds by applying anti-collision stickers to windows: “Those homeowners that want birds in their yard are probably killing most of them, unfortunately,” Kummer says. “The more birds that there are in the yard, and the more birds that are closer to a house and windows, the more likely that a collision is going to occur simply by sheer numbers.” “Use a Lot of Decals — Many forest birds readily dart between branches and leaves, so a single decal will not deter them.”
The New York Times covered the latest study, which only compared two commercial “invisible to the human eye” anti-bird-collision films, it did not study the effect of placing stickers with birds shapes on windows. (the most popular treatment). There have been other studies of various types that seem to show that stickers can help prevent bird-window collisions – but there are caveats.
1) The latest study with window films finds that films on the inside surface of windows are totally worthless – basically, did nothing. These types of films must be applied on the outside surface of the window. These films reflect frequencies of light easily seen by birds, but not by humans, all the while remaining fairly transparent. Pretty easy to apply to sliding glass doors leading to decks and patios and other first floor windows. Not so easy to apply to the windows of office buildings’ upper floors.
2) Other studies (not the new one) have found that adding lots of window stickers to the outside of windows helps prevent collisions. The most popular seem to be bird-shape stickers. Dr. John P. Swaddle, lead author of the latest study and author of many similar studies, is quoted saying: “People who are buying decals and putting them on the windows, they want to do good, they want to do right by the birds.” but if you are putting the sticker on the inside of the windows “Really all you’re doing is some interior decorating”… “You do have to take the extra step of putting it on the outside of the window.”
Additional recommendations from Cornell’s All About Birds for preventing bird window collisions are (excepted):
Treatments for Existing Windows:
To deter small birds, vertical markings on windows need to be spaced no more than 4 inches apart and horizontal markings no more than 2 inches apart across the entire window.
Tempera paint or soap. Mark the outside of the window with soap or tempera paint, which is inexpensive and long lasting. You can use either a grid pattern no more than 4 inches by 2 inches
Decals. Put decals, stickers, sun catchers, mylar strips, masking tape, or other objects (even sticky notes) on the outside surface of the window.
Dot Patterns and Tape. Long-lasting tape products offer an easier way to apply the correct spacing of dots across your window.
Acopian Bird Savers. Also known as “zen curtains,” these closely spaced ropes hang down over windows.
Screens. Installing mosquito screens over your windows is very effective
Netting. Cover the glass on the outside with netting at least 3 inches from the glass, taut enough to bounce birds off before they hit.
One-way transparent film. Products such as Collidescape permit people on the inside to see out, but makes the window appear opaque on the outside.
Other suggestions are to attach outside bird feeders directly to the windows or to locate bird feeders no more than three feet away from the windows (this is the solution we use at my home, along with exterior window screens on most windows).
The estimate of ~ 600 million birds being killed by colliding with windows in the United States annually is of course a WAG (wild guess) – but we should accept it as representing some significant number. If your home has frequent bird-window collisions, you should do something. I would suggest that frequent means more often than “it happened once”, your call.
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If you find yourself opening the plate glass slider with bird stickers on it to let the cat out – you have missed the real problem.
But we need to compare this to another study – even more shocking:
One of National Audubon’s repeating themes in its fund-raiser emails is to repeat Cornell Lab of Ornithology’s 2019 study’s finding that since 1970, bird populations in the United States have decreased by nearly 3 billion birds. Of course, this is an estimate made up of estimates. But there is probably no doubt that there are fewer birds today than 50 years ago, mostly due to changes in land use: conversion of forests to farms, tall grass prairie to rangeland and corn fields, etc. resulting in altered habitat availability. Some of this (very little) may be marked down to window collisions.
“We estimate that free-ranging domestic cats kill 1.3–4.0 billion birds and 6.3–22.3 billion mammals annually. Un-owned cats, as opposed to owned pets, cause the majority of this mortality. Our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals.”
Now, let me repeat that “free-ranging domestic cats kill 1.3–4.0 billion birds…annually.”
Compare that to “since 1970, bird populations have decreased by nearly 3 billion birds” – that’s 50 years.
But for free-ranging cats: in that same 50 year period — 50 times 2.65 (average of 1.3-4.0) comes to 132.5 billion birds killed by free-ranging domestic cats.
When we say “free-ranging domestic cats” we simply mean pet cats that are allowed outside of a home to roam free, at least part of the day and this obviously includes all feral cats.
Now, our first study today said that “between 100 million and 1 billion birds killed annually” “by building collisions in the U.S”. For building collisions read window collisions – very few birds collide with solid walls. Now that is a very wide estimate – the higher estimate is ten times the lower estimate.
But even the very highest estimate — 1 billion a year — is less than the lowest estimate for the number of birds killed by free-ranging cats: “free-ranging domestic cats kill 1.3–4.0 billion birds…annually.”
And there is a simple and sensible solution to this problem as well – keep your pet cats indoors and/or confined to your own property. Just like you do with your pet dogs (who will be picked up by Animal Control if they are found running loose). And this would apply to your pet cheeta, your pet tiger, your pet chickens, your pet pot-bellied pig, pet llama – in fact – like you do with all your other pets.
[ If I’m perfectly honest, there is one pet often intentionally allowed to roam free for a short time each day – pet pigeons. My father-in-law kept pigeons for years, in a coop that allowed them to fly free (when he raised a hatch) and was equipped with a one-way door for them when they returned, which they always did. ]
If you want to protect birds, keep your cat(s) indoors unless they have an outdoor cat run (such as these). And encourage your local community to pass local regulations requiring that cats be restricted to their owner’s property.
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I like to write about interesting things – part of the purview of WUWT.
I like birds. Birds of all kinds. I like my backyard birds. I like raptors of all kinds. I don’t mind when the local raptors take a few of the song birds feeding at my backyard bird feeders. I even like our chickens – which are rather like little dinosaurs.
I like cats. Cats of all kinds. I like pet cats. Buy I don’t like free-roaming domestic cats or, worse, truly feral domestic cats. They are simply little killing machines – it is their nature and I don’t really hold it against them.
Every time I have mentioned cats as a problem, a battle breaks out in the comments. There are those who consider cats (and dogs) to be persons and think that they deserve all the rights to which homeless people are entitled. There are others who feel that truly feral cats should be rounded up and euthanized en masse. And yet others demand that the Trap Neuter Vaccinate Return (TNVR) approach is the best to deal with the large feral cat population problem.
Readers may comment on cats if they chose (WUWT has a very liberal commenting policy) but this essay is really about birds – and windows.
Address comments to “Kip” if speaking to me.
Thanks for reading.
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I have bird feeders and a bird bath in my garden and I have never had a bird fly into one of my windows. This might be due to my windows having vertical venetian blinds so the birds can see my windows.
Bill ==> The vertical blinds certainly will help prevent bird strikes. The danger is when a window looks like a pah to safety — which could be a lighted room or a reflection that makes the window look like an open path to safety outdoors — reflected trees or sky.
Old Gobi Jumper
We found something that worked like majic. One wall of our living room was windows about 30X6 feet overlooking our deck and view of forest and mountains. We put up several bird feeders and water, and started finding dead birds almost every day. I researched several things that did not work. Finally I got bird neting, the kind used for agriculturd and stretched it tight over the entire windows. It is black fine fish line about 1X1 inch squares. I was thinking trampoline. No bird ever hit the net. From outside it showed up vididly, double with a reflection, from the inside.it was invisible, even in photographs of our beautiful view. We sent inside and outside photos to local bird pub that published them and recieved letters saying it worked for them also
We have two bird feeders and a birdbath and have lived with that setup in two rural areas with very different ecotypes. We don’t have stickers or anything on our windows. We lose about one bird every five years. Something in the birds and windows story doesn’t add up.
Ditto. We have four bird feeders (one is a suet feeder for woodpeckers), and go through a 40 pound bag of Audubon Nature’s Blend every three weeks…unless it’s redwing blackbird time, in which case it’s 40 pounds every week. We’ve cataloged 39 species of birds, from black-eyed Juncos to bald eagles. In the seven years we’ve lived here, we’ve had one bird fatality from a window strike, and three stuns followed by full recovery. And our sunroom’s three walls are 70% window and glass door area, just so we can watch the wildlife.
One of our neighbors was having a mouse and vole problem, as were we, and bought a rescue cat to try to handle it. He’s a beautiful black cat with a little white patch on his chest, and deep emerald green eyes (his name is Trigger), and he is outside as much as he wants to be.
After his appearance, the mouse and vole infestation problem went away. He likes to hang out on our deck and watch the birds and the squirrels (we feed the squirrels, too), and occasionally he’ll make a half-hearted attempt a chasing one or the other. I’ve only seen him get one bird in four years. He’s gotten his arms around one squirrel, but didn’t know what to do next, and let it go. We also have foxes, and I was always worried about a fox getting hinn. Well, one day Trigger was sunning himself on our deck, and the biggest fox I’ve ever seen came strolling through the yard. My heart sank, and I prayed that the fox wouldn’t notice him. Well, as soon as Trigger saw the fox, he leapt to his feet, and took off at full speed toward the fox – which saw him, and did the only double-take I’ve ever seen a non-human creature do, just before taking off in terror. Trigger chased that fox 100 yards into our meadow, but apparently lost him. What a bad-ass cat!
He’s not feral, though. He really loves to look in on us through the doors and windows, and likes it when we talk to him. His domain is roughly 100 acres of woodland – all of the properties here are 5 acres, minimum. I suspect that his rodent diet is sufficient. The bird population has done nothing but increase greatly since we’ve been here. He might add frogs to his mouse and vole diet during the summer, but has never put a dent in their population (they annoy one of our neighbors in the summertime because they are almost deafening at night).
I’m not buying the “data” on bird deaths from collisions with “residences.” I’m 67 years old and have lived, and continue, in houses in very good bird habitat. I also feed the birds many months of the year. I can count the bird strikes on my windows that resulted in death on the fingers of one hand. Most of the time, the little guy sits there stunned for a bit, then flies away.
Years ago when we lived in Minnesota, we had a robin that repeatedly – dozens of time per hour – crashed into a window trying to drive off that persistent competitor. He would leave “wing prints” on the window. Never killed him. On the back side of the same house, a ruffed grouse did commit suicide crashing into a glass slider. But, that was an exception.
We’ve had a birdbath < 10 feet from a kitchen window that is 4×5 feet, for 20 years. No problems.
I have several Hummingbird feeders and a bird seed feeder hanging on my front porch and near my back steps for the last 22 years that we’ve lived in our current house. We have both Song birds and Hummers flitting around on a regular basis during spring and summer. We have a couple of nests in our front bushes and the songbirds fledge 2-3 times per season. We also have 11 windows (half being 40″ x 62″) with 2 facing the nesting bushes and feeder area (front of the house). 22 years and not a single bird strike.
I have lived in 14 different houses with about 160 windows over the last 60 years and can’t even count on one finger the number of bird strikes on our windows. There’s none to count, not a single one.
As far as bird strikes go, Manhattan Island (NY, NY) has some 47,000 buildings containing some 30M windows and is just one of hundreds of cities (rather small of stature though being limited to the size of the island).
With over 4 million cities in the world and the potential tens to hundreds of trillions of panes of glass in their buildings, houses and apartments, bird strikes are in fact quite low relatively speaking. And exposure potential is fairly high.
Bryan ==> Admittedly, these types of statistics are simply WAGs — wild guesses — made as extrapolations from rather small data sets. They may not be valid at all.
Nik ==> Local features probably have the greatest role leading to bird strikes. Is is what the bird sees on an instinctual level as it flees in panic from some threat that caused the strike. And some of thse things we don’t see — as birds see differently.
No bird strikes, no worries!
In my almost 60 years on this planet, I’ve had a bird crash into a window of a house that I occupied exactly once.
It smashed into a second floor window and fell down onto the deck below. It was a small bird but hit so hard that we all heard the thump even though we were all downstairs at the time.
My daughter (about 7 at the time IIRC) was beside herself, she was first on the scene, picked it up and brought it inside. Much to her surprise, a few minutes later it “came to”, took flight and flew frantically around the house for the next 20 minutes as we all tried to figure out how to steer it out a door or window without injuring it further. I think it did more damage to itself in its mad scramble to escape the house than it did smashing into the window in the first place. (Pro-tip takeaway, don’t bring suspected dead birds inside the house until you’re SURE).
Who knows, maybe it suffered a permanent brain injury and forever had to consign itself to having a wise owl manage its finances, but after it woke up, it sure seemed no worse for wear to us.
I’m also a little skeptical of this statement: “But there is probably no doubt that there are fewer birds today than 50 years ago, mostly due to changes in land use: conversion of forests to farms, tall grass prairie to rangeland and corn fields, etc. resulting in altered habitat availability.”
That may have been true during the 50 years between, say the turn of the 20th century and the 1950’s, but my understanding is that advances in farming technology have actually resulted in an increase in forested land in the US in the past 50+ years. Cities and suburbs continue to expand for sure, but cities only occupy about 3% of the land mass in the US. Forests, on the other hand, make up approximately 25% and growing.
I’m also curious as to how they came up with that number of birds killed by cats. My suspicion is that’s another wild-ass-guess statistic. Color me skeptical.
Incidentally, you know what HAS been increasing dramatically in the past 50 years that could be contributing to the reduction in bird populations? Windmills.
Sailor ==> I have written specifically on this point — the State of the Birds reports.
The major issue is that things change, without our specific permission. When things change in the natural world, other things change.
On the cats issue, that is yet another extrapolation — but it is at least backed by evidence of “kitty cams” tracking the lives of free-roaming cats. The major effect on birds of free-roaming cats is the robbing of nests of hatchlings in ground nests and low nests — nests where curious cats hear the chirping of nestlings. The cats gobble them up. Cat do occasionally catch adult birds, too, but not that many. Small mammals (bunnies, chipmunks, voles, young squirrels) and reptiles (lizards, small snakes, etc). I will tell you this — no cat person believes that cats kill that many birds and small animals. Not-cat-persons find it far easier to believe.
I have had indoor cats for 37 years. They are a huge menace outside. One cat killed 15 nice in the house before I finally discovered where the mice were getting in. “The General” had 15 stars, but never ate any of the dead mice.
My current cat Mr Sneaky caught one mouse in the house since 2014 and I only know that because I found the tail and back legs. He ate the rest of it.
Cats are vicious killers, but so are the hawks who nest next door. Some people too.
Biggest killers of pigeons here are sparrowhawks. And cars.
I shot a rabbit from this window. Meant to collect him but the next day all that was left were a couple of bones. Fox? Badger? Owl? Crows? No idea.
I nearly got hit on the head by a pigeon falling out of the sky. Why? No idea.
Birds DIE. In HUGE numbers, and stuff eats them.
Sometimes it’s a cat. But mice are preferable. Or rabbits. Cats used to stay out for days living off rabbits
In regard to predation, the belt of trees near us had ravens at one end and crows at the other. It is noticeable that since the crows moved across the bay, the number of small birds increased.
For the record, I’m not a “cat person” by any stretch of the imagination. In fact, I quite dislike them generally speaking, not to mention being mildly allergic to them.
That doesn’t mean I’m going to accept statistics that seem suspect to me just because I’m not particularly fond of the subject of those statistics.
I clicked the link you provided above but see no support for the claim that cats kill xxx number of birds per year.
I’m not saying that cats don’t kill a significant number of birds, I can’t make any claims either way, I’m just saying I don’t see how anyone could possibly come up with a plausible estimate of that number without just pulling it out of their hindparts.
I admit, I’d never even heard of “kitty cams” and had to look that one up. The vast majority appear to be located in animal shelters in fixed sites overlooking the pens where kittens are kept, but I did find one story where the University of Georgia fitted cameras on 55 cats in Athens to study their behaviors. If found this part especially interesting:
I paraphrased in a few places to save space, you can read the whole thing at the link above for context.
It actually doesn’t surprise me that the majority of the cats studied didn’t hunt…they are domesticated; they’ve never needed to hunt and likely never learned to do so from their parents. If anything they’re probably over-fed so it’s doubtful they’d be hunting for food, they’d only be doing it out of instinct or boredom. I’d say feral cats who do hunt for food would be much more significant threat.
Regardless, only 30 percent of the cats studied were successful at hunting and only a minority of that success involved birds.
So, nothing in that study dispels my skepticism about the numbers being touted.
Of course, that’s a small number of cats in one location that may not be representative of the entire cat population of the US, so it doesn’t disprove anything either.
Overall, absent further evidence, I remain skeptical of that particular “statistic”.
We had one cat that was outdoors at night and was an avid Hunter. Many mornings we would go out to the garage and discover the corpses of between 2 and as many as 7 large sewer rats (most 9″ or longer plus tail) lined up on the concrete steps in front of the door. I guess he was trying to feed his family (us) at least until one morning he never returned…Rats must have gotten the upper hand.
Bryan ==> Trophies! Quite a common behavior — both things. Cats that are allow to free-roam often disappear — which is one reason vets urge owners to keep their cats indoors. Cats are natural hunters — predators — and just the right size to be prey for large predators. Depending on where you live the list of things that will kill cats differs.
In my area the list includes large raptors, coyotes, bobcats, wolves, dogs, feral dogs, and feral cats. There are also deranged humans that shoot free-roaming cats.
My daughter had a number of cats. At least two of them often left ‘gifts’ on the doorstep: lizards, birds, mice, large insects, etc.
Yes, I have been told on too many occasions that “my dog does not bark” when the mutt clearly carries on for hours at a time.
My dog does not bite
Inspector Clouseau routine:
1.5 minutes of great comedy
Pink Panther Strikes Again – Peter Sellers as Clouseau, “Does your dog bite”? – YouTube
So who is going to kill the rats and mice ?
And one of the worst enemy of birds is the Magpie. A very smart bird.
Strange that all the claims of the billions of our feathered friends murdered in their prime by evil windows and cats were promoted once the hard evidence of whirligig kills of birds and bats appeared.
In 75 years I’ve known one bird killed apparently by flying into house windows. I keep a couple of cats who frequently kill mice and rats. Sorry, not apologising and we do live near a river. We find the mouse gall bladders under the kitchen table and next to their cat-flap, two or three a week.
Also strange that the bird fanciers are especially keen on raptors that kill other birds, mammals, rabbits, lambs, chickens etc. (The raptors that are especially threatened by whirligigs.) The twitchers say that raptors are very important to eliminate weaker and sick birds, lambs etc further down the food chain.
I admit that my cats do kill perhaps two or three birds a year. Most often fledgelings who have fallen out of their nests. But the ‘survival of the fittest’ argument apparently doesn’t extend to cats.
And I”m certainly not keeping my cats indoors. Dogs have masters. Cats have staff. I’m happy for them to go off mousing whenever they want some sport or a snack. But I will certainly reconsider if they start dragging eagles through their cat-flap.
Forgot a speciality of one of my two cats, the eleven year old tabby neutered Tom. Snoring beside me as I type, (neutered black Jenny cat sleeping on my knee).
When the tabby was younger he perfected climbing the trees between our house and the river. About 25ft high, I guess, now 35ft. He climbed up and back down again, straight up and down the trunk. Back in the kitchen he would spit out from bulging cheeks, one pigeon egg. This was apparently a present for my wife. When she ignored it, the cat patted the egg against the skirting until the egg cracked. He then sucked out the contents.
When young he managed perhaps a dozen eggs a year. Pigeon egg shells both in kitchen and garden. He’s now too old and plump, I guess. Perhaps those need to be added to his tally. Absolutely no shortage of woodpigeons, i assure you.
I mentioned this to three or four veterinarians, none had heard of this cat tactic. But it is certainly true!
Martin ==> Two issues in your comment: Cats leaving trophies for their owners and the eggs thing.
On trophies, cats do that (many cats, anyway). One year when we returned from vacation, there were seven flying squirrel tails lined up on our door step left for us by our cat, Grey. Just the tails, mind you. They look a great deal like feathers, by the way. I used to wear one in the band of my Scoutmaster hat to the bafflement of all the Nature Directors at Scout Camp.
On eggs, I have never heard of a cat bring whole eggs back as trophies, or even showing an interest in unhatched bird eggs. I’ll check some of the kitty cam studies to see if they report this conduct in other cats. VERY interesting.
I’m now living in a small community (less than 1000 people, 55 miles from the next “town”, about 100 miles from the nearest city) for the first time in a very long time.
Having seen evidence of local mice (who are very messy and who chew up a wide variety of things that humans need,) I would sort of like to get an outside cat but being responsible for same isn’t very appealing.
My understanding is that automobile crash victims often don’t know about their whiplash injuries until well after the accident. Would birds be different?
The birds killed by cats is utter bollocks. See my post above. 92% of birds have to die before reaching breeding age. Mostly it’s starvation or cold. Cats merely scavenge the bodies. Any bird that can fly is pretty much cat proof. Cat’s cant fly.
LKMiller ==> The death factor comes from the speed of the bird and that depends on how long of a runway they have. Birds feeders closer to the windows are better — mine are three feet and I have lots of brush and trees where the smaller birds can seek cover.
Birds that hit windows at slower seeds are stunned and recover, at least apparently — never can tell if they fly off and then die of a concussion.
Personally, I don’t worry about bird strikes at all. MY birds are smarter and above average so don’t run into windows….
What about windmills?
English birds don’t seem to fly into windows in my experience but we have lost a couple of cat=flaps to a brain-dead feline pet smashing into it at high velocity only to find it locked. This same wretched creature also managed to break a car window. The intelligence shown by English birds is in marked contrast to that shown by our flock of bird brained politicians of all parties who obviously have nothing but feathers between their ears
I agree. I have lived in my current property for 32 years. My house paddock is about 2 acres with dozens of flowering trees & over 100 flouring shrubs. Lots of Grevillea which attract nectar eaters & seed eaters. I also have apples, peaches plums & apricots, all attracting various species, who leve us very little fruit, but even better, mulberries, Brazilian grape & dragon fruit which attract hundreds.
I do feed the birds a number of feed stuffs, randomly a few days a week to avoid dependence. When I have only seen a couple of pigeons & magpies all day, with in a few minutes of spreading feed on the grass I will have 50 birds squabbling over it, there are a lot of birds in my house paddock.
Yes we have had a few, but very few window strikes. Most fly off, but a few are stunned. I pick these up & put them in a hanging basket in our open fernery. Only one has not recovered & flown off.
I have to wonder is someone in academia is grant hunting.
I get carrion crows and jackdaws and once a baby owl, falling down my chimneys. Only one didnt make it – he fell down a chimney there was no escape from and died after a couple of days. I lit a fire and he vanished up in smoke
And how many birds are killed annually by wind turbines?
The average wind turbine kills 500 birds and bats annually. Since the United States has 70 thousand wind turbines, this extrapolates to 35 million birds and bats killed annually.
That’s interesting. Here in Saskatchewan, the environmental assessment reports for new wind installations use an average of 9 birds killed per year, and base that on the estimate for Alberta installations. Naturally the environmental consulting firms do their bird counts early in the spring before migrations, so their totals are very low and restricted to a few magpies, crows etc. When I point this out to environmentalists, including biologists who work for EGOs, climate change trumps the bird slaughter.
Amazing how those who have the gall to call themselves “environmentists” prioritize futile attempts to manipulate the Earth’s climate (even IF the underlying support for such a course of action were not so pathetic) over the protection of landscapes and wildlife.
Interesting report Bill, I hadn’t seen that one. The last one I saw placed the number of bird strikes at about 500,000 for the 370,000 global turbines and bats at over 750,000.
The article I linked to explains why the wind lobby’s bird death totals are ludicrous underestimates of the true carnage which wind turbines are inflicting on avian life. My experience of the wind lobby in Scotland is that I have never met a bigger bunch of lying scumbags in my life. They will literally say anything for money.
I have read the bird death count is usually too low
Windmills kills insects
Small birds come for the dead insects and get shredded
Big birds come for the dead small birds and get shredded
Predators come for the dead big birds
Nature’s clean up job can significantly reduce the dead bird counts
Injured birds can die elsewhere.
Windmills are better at bird and bat shredding than at generating electricity … but the so called environmentalists could not care less.
Plunk you magic twanger Froggy, it’s time for the bird chopper:
They should all get their “kills” memorialized like that. Of course, even including the whole supporting structure, they’d run out of room in a year…
On average 1.4 birds and 2+ bats per turbine (the .4 is for Raptors 2 Raptors for every 5 turbines). Fortunately their use is minimal so potential exposure is relatively low as well. But if they’re allowed to proliferate and liter the countryside potential exposure rates will increase exponentially
Nik and others concerned with wind turbine bird kills ==> The greatest problem with wind turbines is the killing of LARGE birds — large raptors which soar. These raptors reproduce slowly — unlike songbirds that can have two and three broods per year.
Right, Kip, and add in vultures also, drawn by the death smell. My experience walking along a line of windmills just NE of Casper, Wyoming, early on a Monday morning, was 20 visible small birds (sparrows, fiches, meadowlarks, etc) 2 golden eagles, 2 hawks, and 1 vulture, along a line of windmills, but only walking to 2 of them. As I have commented before a clean-up crew arrived around 8:00 AM and threw dead birds in the back of a pickup truck. I call them a clean-up crew because that’s all they did, drive from one turbine to the next, loading up the birds. Let’s say the birds I saw were 2 or 3 days accumulation, sometime Friday to Monday morning. This gives an estimate of 4 small birds and 1 eagle or hawk or vulture per day per windmill.
Ron ==> Thanks for the eye-witness report. Do you do this regularly, or was it a one-off?
“a major anthropogenic threat to birds”
I wondered where they’d all gone /sarc
The major anthropogenic threat to birds has to be wind turbines and solar arrays like Ivanpah
Are we running out of birds now? A bird apocalypse is upon us?
Kip: “I like birds. Birds of all kinds.” I recently asked an Argentine friend what the slang name for lawyer was and he said “cuervo”, which is crow. I asked him why cuervo, and he said “because when you’re dead they both peck your eyes out”. I suppose if an attorney reads this and is offended, I should be sorry…
Ron ==> When I was a teenage California surfer boy, attending a high school in Watts (LA)…where I was the racial minority — there were two other surfers in the entire school — and this was during the Beach Boys craze.
One of the surfers was a Latino kid — he had to hide his surfboard at my house so his friends would find out. To this day, I don’t know ios real name, though he was a close friend. We just called him:
Thanks for calling up the memory.
(Good lawyer joke too!)
Best lawyer joke:
Q: What is the difference between a lawyer and a rooster?
A: A rooster clucks defiance.
Best wind turbine killing bats, birds and whales joke?
It’s no joke and not funny. The jokes are the virtue signaling nitwits who promote such utterly stupid ideas.
I like birds. We had feeders, but the cost of feed got just ridiculous, so we stopped. A funny thing, when a new development went in on top of a ridge line, all the turkey vultures were displaced. They took to roosting on rooftops nearby and some of the taller trees. A lot of people were freaked out, but I just took it as an unusual opportunity to observe birds I wouldn’t normally see. Well, except on the side of the road on a deer kill.
Not sure where you live, but at least in my neck of the woods, bird seed is still fairly affordable. In my experience, birds prefer sunflower seeds, so don’t waste your money on “mixed” seeds that contain a lot of stuff birds really don’t like. Before Biden inflation, I could get a 50 lb bag of black oil sunflower seeds for $20-22, and this amount would last most of the winter (Oct to May). The last time I bought a bag it was $30, and increase for sure, but still quite affordable.
Suet at my local grocery store sells for $1.99/lb.
IIRC, we were going through a 25 lb every 2-3 weeks. That adds up.
Estimates of mass deaths like these are suspect because they have no way to accurately count them so they rely on statistical models driven by assumptions which may be wildly wrong.
Feral cats certainly can be a problem, and just like the inundation of non-native Burmese pythons in Florida, it comes down to irresponsible pet owners. Spay and neuter them. If you can’t—or don’t want to—take care of them any more find someone who will. If you can’t place them, do the responsible thing and euthanize them or give them to an animal shelter if you’re squeamish.
And there is something odd about people who anthropomorphize their pets. They’re not human. They’re domesticated (and sometimes not) animals. Be responsible and take care of them but for heaven’s sake don’t do this:
stinkerp ==> Yes, far too much extrapolation — and very wide estimates.
For bird strikes, if you had a lot in your home, you would know it and should do something about it.
In our upside-down world, many people have pets in place of children — and treat their pets better than they do children.
I now someone who has a small dog and dresses it every cold day. The dog tries to hide in order to not go outside otherwise. People are not the one animals that get cold.
The idea that homeowners who attract birds with feeders and baths “are killing most of them” by enticing them closer to windows than they’d otherwise be is so obviously rubbish that it makes me doubt the numbers in the 2014 study. And there’s no comparison offered for perspective: How many birds are there in the country to start with, if an average of 600 million dying annually still leaves any standing?
We live on a rural Texas mix of pastureland and timber, and I’ve seen a greater variety of bird species here than anywhere else I’ve lived. We entice birds close to the house with feeders and multiple clean water sources all year long. The windows on each side of the living room alone are 90 sf, and in two years not a single bird has offed itself on them. In fact, I saw more collisions in Illinois, where I *didn’t* feed birds, but even then it was just 2-3 per year, and not all of them died.
As for cats, they should be confined indoors for their own safety, and everyone talks about the toll they take on birds while leaving out their impact on rodents.
I’ve seen reports with estimates of anywhere from 40 – 130 billion (WIKI) to upwards of 200 – 400 billion (AMNH) birds globally
NAT GEO places their estimate at 50 – 430 billion covering both ends
QODTMWTD ==> Yes, that statement is probably a mis-interpretation of something the scientist said. I will write to him and ask.
Bird strikes depend overwhelmingly on very local conditions — what reflects in your window that the birds see when they are nearby.
And somehow there are lots of birds around….it’s like they have adapted and they make more of them. There continues to be 7-10 Billion of them. If this were true what would the world look like. Not the non-sense they say.
From my experience large areas of glass reflecting a garden or other large area of green ery is what causes collisions.
Thirty five years living with a window and garden combination like that meant a handful of deaths per year. Normally staying size and above.
Had several Sparrowhawk dinners and magpie nest raiders.
Never saw cats take out anything but odd birds mostly small rodents and lizard tails
Ben ==> absolutely correct — it is what the birds see that counts.
You won’t see most of what cats kill — but they do kill anything of the right size that “looks interesting” —-
Boids in Brooklyn where I lived before moving to Michigan.
How about those bird and bat shredders now ruining our electric grids?
Fellow bird and cat lover. Dogs too. We have a year-round thistle feeder, bird bath (heated in winter), a four suet cake feeder and two hummingbird feeders (for warmer weather). We have a cat who stays inside at all times.
We also have a wall of 100% glass on the east side of our living room that starts at 8′ and peaks at about 11′ feet. It has a four-foot roof overhang outside. See first photo at the link below:
Honest Climate Science and Energy: The editor, his home, his wife (on right) and his cat, if anyone cares?
In the 37 years we have lived here, only a few of birds have hit the window that we know of. We have found only a few dead birds, and have rescued some of them –we put them in a place where they would be safe until they (hopefully) wake up, and most do.
We bought this house for the windows. We can’t be responsible for the few birds that fly into those windows in the past 37 years. They must be confused leftist birds. There are never going to be stickers on our windows. Honest Climate Science and Energy
Richard ==> Beautiful gardens.
I wouldn’t put stickers on the windows either unless I had a family member overly upset by bird strikes….and then it would be for the family member, not the birds. (and I am a bird lover, just not a fanatic.)
A certain person who prefers to remain anonymous insisted on me adding four photos of the rock and shell garden in front of our home today, for which “you never lifted a finger to help build”.
Honest Climate Science and Energy: The editor, his home, his wife (on right) her rock and shell garden, and our black cat, if anyone cares?
We always had issues with our picture window and realized that the sliding glass door, opened on the otherside of our livingroom, created the illusion of a fly through. Once we started closing one or the other we no longer had any issues.
brycart ==> Cool — good trouble shooting! Birds are very visual and make decisions instantaneously and instinctively when in the flight (of fight or flight) mode.
seems to me that if we didn’t have so many things killing so many birds, we would soon be over run by the little feathered pests (sark)
jvcstone ==> Actually, Population Dynamics would take care of the “problem” — Population Dynamics are 1) Chaotic (Chaos Theory sense) and 2) controlled by resources and 3) predator/prey relationships (in some cases).
Only in odd instances (think passenger pigeon) do we see run-away population numbers. And because it was extraordinary, their demise was run-away too. The Boom and Bust effect seen in chaotic population dynamics.
The National Audubon society has gone off the rails and infested the local chapter so much that I have given up – I just don’t participate any more.
My house has usually been hit by a dozen birds a year, until I added large roofs over the patios. In the past year, an uncovered window was hit but the bird landed in snow, and a minute later flew off.
Had I used the money I spend on seeds for birds to buy Berkshire Hathaway stock (years ago) I’d have a million-dollar gain.
But I like little birds and quail and tolerate the Jays and Magpies.
John H ==> Agree with you on this: ” The National Audubon society has gone off the rails and infested the local chapter so much that I have given up – I just don’t participate any more.”
I do support local Audubon efforts if they are rational and based on the values of local members to do sensible local projects that protect bird habitats that might otherwise be lost.
But like all large organizations with massive money-motivated bureaucrats at the top, local groups get cluster-bombed with nonsense from above. Local leaders who seek approval from above go along to get along – and many end up brainwashed
When I was a kid we had several birds hit the sliding glass door which was under the patio cover of 15’ most had been chased by a hawk so we put up a hawk silhouette from the Audubon
In my house never have seen a bird hit and I have feeders out year round also a hummingbird feeder
Mike ==> Ah, that single hawk silhouette probably didn’t do anything — but better than nothing.
I too have year around feeders (seed mix for songbirds, oil sunflower for everybody, thistle for finches, whole peanuts-in-the-shell in wire feeders for woodpeckers and other “pecking” birds and finally, deer fat or pork fat or bacon scrapes or suet for all). And, of course, sugar water feeders for the hummers, in season.
We do get the occasional hawks or falcon that appreciates out concentrating his food in one place for many hours a day. We do not hold it against him — he has to eat too.
Birds sometimes aren’t concerned about our fake predator scarecrows. The picture below was the WSU Extension’s recommendation for getting barn swallows from building nests in our carport and crapping all overour cars
I remember reading that one species of small bird in the UK needed to have 5% of the offspring survive to breed for the population to remain stable. I would expect that birds differ in whether they tend toward a “R” or “K” breeding strategy – eg, have few babies and put a lot of effort into each one versus have lots and hope some survive.
The fact that marginal farm land is returning to woodlands in many places should be good for both birds and their predators
Fran ==> Recruitment rates (the number/percentage of young that survive to become part of the breeding population) differ between species. Generally, smaller birds have larger broods (more eggs, more chicks) and often more than one brood per year. Penguins have one (sometimes two) chicks…robins and finches, half a dozen at a time.
Marginal farmland return to woods is good for birds preferring “transitional forest”. Bad for those preferring open pastures and grassland. In my area, dense forest is almost bereft of birds. Too dense, too little food. Same with the deer. Get to the edges of the forest, where there are meadows and streams and brush — and birds and deer galore.
I’m sure there is a model in there somewhere.
Ed Z ==> Whenever there is “data” there is a model. Even simple counts are a model, as they assume that the objects being counted are the same as the totality of the things to be counted (sometimes that is right — how many apples in this bowl right here at this exact moment?)
But not all extrapolations and estimates are bad — one just needs a rational way of deciding how accurate they might be. The estimates given in the bird strike and cat-kills-birds numbers are very very wide — up to a factor of ten. This means “We don’t know”. But if the lowest estimate is high enough to create real concern, then “Bob’s your Uncle.”
The model for forest management once widely used by peoples who lived in the same area for many generations — without any interfering central govement.
I’ve been putting up Acopian BirdSavers and they’re working for me. I used to have 2-3 bird strikes a week, now I have none.
At first, they looked like bars on the windows, but now I only notice them when they sway gently in a breeze (the Zen part of the curtain).
Picture is of a stunned Redstart that eventually flew away.
Roy ==> Well, thank you for the endorsement of the Acopian BirdSavers. I had never even heard of them. From the pictures, I assumed they would be very effective as the dispel any visual idea that the window represents a path to safety. I too thought they would like like bars, but am glad to hear that the gentle swaying in even a slight breeze obviates that impression.
And with that many bird strikes, you definitely needed to do something!
Nice picture too!
Hmm, sure, we believe you…
Redge ==> This is quite the norm for many studies of various types. From the company’s point of view, they get disinterested scientists to prove their product is effective (if it is not, then they just don’t advertise the study, no one would read it without press releases).
In this case, they picked an academic that has been doing bird strike studies of all types for years, and offered to fund the study of their product and a similar by another company product. Turns out both are effective if and only if applied on the outside of the window.
Industries fund a great deal of research and are careful not to influence the findings. Mostly effective — what we need to watch for are in-house studies being passed off as disinterested studies.
Yes, I know, Kip.
My comment was meant in jest, but I’ve worked at a university where industry has sponsored research and know for sure, it does happen when the researcher is over pally with the industry contact.
Aha! To save them from the bird choppers, windfarm owners should use holographic projections around each killer column.
lan_e ==> There are studies looking into ways to make wind turbine blades more visible to the birds most often killed. Another here.
Just like the bird strikes I write about in this essay, the problem is that the birds cannot see or mis-perceive wind turbine blades and are literally blindsided by them.
I have seem other painted-blade solutions — stripes, bands, etc.
This same sort of perception problem happens with cougars in Florida — somehow the cougars fail to properly perceive the speed of approaching cars when the cougars are crossing highways. The cougars stop and stare at the coming cars….and then the car is there and hits them. And cougars are otherwise extremely intelligent.
We have glass ornaments hanging in a bank of back windows upstairs, which reflect light, and thus have no problem with bird strikes. Downstairs on occasion a bird may bump a window, and might be momentarily stunned. The cats have a yard, fenced in by about 400′ of 6′ high deer fence, and a cat door so they can come and go as they please during the day (they are in at night). One cat (female) occasionally will snag a bird, but they mainly go after mice, moles, and the occasional chipmunk. The fencing is to keep them safe from all manner of possible dangers, but yeah, nice to know they aren’t killing birds (except on rare occasions).
How about attaching Red Reflective streamers to the tips band along the blades that reflect the light as they stream out behind the blades. A similar tactic is used on some vineyards to convince birds that the field is afire
Bryan ==> Sounds like an idea — the object is to make the blades and their movement apparent to the birds.
killing birds is probably the least evil of wind turbines
Bruce ==> Good on you — a sensible but not too restrictive plan for your cats. With that much space, your cats are probably not tempted to roam beyond the fence (though a 6 ft deer fence would not stop them if they really wanted to get out). Keeping them in a night protects the cats for many dangers — some you may not even be aware of.
We have coyotes, wolves, bears, large raptors, feral dogs, feral cats and bobcats to name a few of the risks to domestic cats.
Your cats may enjoy nestlings if any birds nest low to the ground in your bushes though — but everything has its trade-offs.
Anything shiny and tinkling with a little motion will discourage birds strikes….little stripes of 1/2 recording tape are hung on the wires of vineyards in California to spook the birds. They sparkle in the sun.
Maybe instead of stickers of birds flying, people should apply stickers of cats licking their chops. Probably would do a better job of discouraging birds from flying towards the window.
AGW ==> I don’t think it matters what the stickers are — dots, planets, animals, squares, one site even suggested Post-It Notes!
The only thing I would not suggest is stickers of plants or vines…which may look like possible refuge to the birds.
Kip, agreed on keeping the cats indoors. Decades ago my cats were free to go in and out and they averaged 6 years lifespan. For the last 15 years we have kept them inside, our current cats have never been outside so they don’t try to escape out open doors or rip open screens in windows to get out, and consequently our 3 cats are between 9 and 13 years old and all going strong.
And not ki!!ing birds.
Our “new” place in central calgary has lots of windows, the neighborhood has lots of birds and we have a feeder to pull them in all thru our 11 months of winter. That part of the yard is carpeted in bird poop proving the number of visitors.
No birds dead after hitting windows, 20 months here now. No stickers on the windows.
I do use the Cornell bird app for identifying birds, data goes into their database.
Pat ==> Kudos for keeping your cats indoors!
I make excuses for “working cats” — barn and stable cats whose job it is to keep rodent populations in check. They stay in their work area and do not roam.
11 months of winter — LOL
And yes, if you love your pet cat — keep it indoors or only allow it out in a proper cat run.
The Cornell Bird app is MERLIN (which I also use and is on my tablet, my laptop, and my phone).
Coincidentally, my son’s 22 ft Rhodes sailboat is named Merlin, for the bird, not the wizard.
over 5 decades and I have never found a dead bird under any of my house windows. There must be some very serious serial bird killer windows out there.
astonerii ==> All very very dependent on local conditions. Some people have lots of windows and few or no bird strikes, one reader reports having 2 or 3 a week, before taking measures to prevent them.
At our house in Utah, about two years ago a bird flew into one of four picture windows offering a panoramic view of the Wasatch Mountains, hard enough to crack the window, but not hard enough to kill the bird. Although we never found the bird, we suspected a bird impact because the window was too far away (and also uphill) from the back fence for someone to throw a rock at it from a neighboring yard.
Back in the 1970’s, the library at the college I attended had large picture windows, and the intake ducts for the ventilation system were below, covered by metal grates, and there were usually several small dead birds on the metal grates. Apparently the birds flew toward the library, got caught in the downdraft, and crashed on the grates. Students tried to remedy the problem by taping pictures of hawks or other predatory birds to the window (particularly on the ground floor) to scare away the small birds.
My parents also owned a cat when I was growing up in New Jersey, which would usually kill about three or four birds per year (as well as far more mice, chipmunks, and squirrels). If cats kill 4 billion birds a year, it would require about a billion pet cats similar in hunting skills to my parents’ cat, which seems to be a bit of a stretch for a country with 330 million people. How many American families really own three cats allowed to hunt outdoors?
Somehow, it seems like the most efficient bird-killer is wind turbines, far beyond the casualties inflicted by pet cats and windows.
Stevez ==> Well, there are about 90 million pet cats in the USA and an unknown number of feral cats. The stats on cats killing birds come from “kitty cam” experiments (quite a few of them now) that place a miniature video cam on pet cats for a week at a time and then count the kills. These studies have been repeated in many countries with the same shocking results. The worst damage is from cats killing hatchlings and nestlings of ground and low-nesting birds — not just adult birds, though some cats become quite skilled at what I believe the cats view as “sport”.
There are estimates from surveys on cats allowed to roam at will, at least part of each day, don’t have the data readily to hand.
As I have mentioned above, wind turbines kill mosty big birds, not songbirds (because they are harder to hit?)
Your bird strike must have been large bird moving at speed to crack a modern plate glass slider.
Your library windows with stickers may have been effective if the birds could see the pictures though it matters little what images were of — cats, dogs, spots, triangles, or raptors….it only needs to clue the birds that SOMETHING is there. They would be more effective on the outside.
Note: Even people walk into plate glass doors if distracted. Safety regulations had to be changed when I was a kid because way too many kids (and adults) would run through plate glass windows and be cut up by the falling glass. Now safety glass is required.
The only True and Humane solution is to immediately ban all windows… And windmills too!
GreatGrey ==> yes, there are draconian and nutty solutions of all kinds to all problems. In this case though, in your home, you only need a solution if window strikes are a problem — too many strikes on the same window means you maybe need to do something.
Wind turbines do need solution to the killing of big raptors.
The estimates seem high but I don’t see any way of confirming or denying it. However …
In 2020, there were approximately 518.3 million chickens in the United States.
Compare that number with the median estimated annual bird vs window deaths at 599 million (above). I have a lot of glass and a lot of birds around my house but I know that the number of chickens I eat in a year is far above the number of dead birds I find.
And before you ask, there are no cats around to walk off with the carcasses.
roving ==> I doubt that cats make off with dead birds. Cats like moving interesting targets — its in their genes. (Think cat toys) — even laser pointers). Estimates are very wide…uncertainty is high.
Not all windows are subject to bird strikes.
If the bird death stats included chickens and turkeys, the numbers would be much higher.
I strongly suggest that anyone at risk for finding this ariticle persuasive look up “fear factor” in relation to biodiversity. A good start is to be found at:
I confess to having window stickers both outside and inside some of my windows. They’re ugly, overpriced, not very effective, and outside they fall off and blow away easily.
OTOH, I’m a keen armchair bird watcher and photographer. I have several bird feeders, and go to consicerable lengths to make them inaccessible to the neighbourhood cats. But I find the birds unappreciative of the security measures provided. Many prefer to feed on the ground .
I spend a lot of time sitting by the windows overlooking my backyard, and I often have a dozen or more birds on the feeders. And when I hear a window collision, I’m quick to look for bodies, but can’t say I’ve found any dead ones in many years in this location. They appear to bounce off and keep flying.
I have a single cat adopted from life in the street. He’s neutered, but can’t be cured of his urge to be out and about and to hunt, no matter how amply jhe’s nourished at home. He insisted on going out a -22C last week, when no birds had been around for quite a while.
I guess he’s a bit of a maverick, seemingly preferring non-native species (sparrows) to native ones. But mostly he goes for mice.
I bother to comment on this because I feel it’s the same sort of hate-mongering “research” that would disarm all lawful firearms owners, except our big brothers, of course, on the pretext of stopping violent crime. Only in this case, the target is feline pets, whereas the real problem is unneutered feral cats.
otropogo ==> The studies are not meant to add to the “fear factor” however, advocacy groups use the studies, with exaggeration and without caveats, to scare people into donating money to them.
There are better window appliques for outdoor use that don’t fall off or blow away.
Like all types of collisions, the results depend on speed and mass and direction.
Your cat is not a maverick, about 50% of domestic cats are natural hunters — can’t help themselves. Some cats are not interested in active hunting.
The solutions are simple for cats, keep them indoors.
I’ve got low E glass at http://theviews.org/ and it’s pretty much opaque to UV, which birds can see. So, in spite of all that glass, we never get a bird strike. Some of the gold and bald eagles have found out that the vertical wall of glass produces a really good updraft, so I’ve had them get 8-10 feet out from the glass. That is quite a site!
mcsandberg007 ==> How big are those windows that give an updraft? Great story, thanks for sharing. Oh, found the website — fabulous home! I see that the updraft is also created by the site itself.
My knowledge is very limited but the few people I know who claim window success believe it to be because their window sticker (single) has the silhouette of a hawk.
Andy ==> It is questionable that the shape matters — but, anything that works, works.
This most supportable idea is that anything that the birds can see that allows them to identify the window as something (and not nothing, not just open space) does the trick.
Seems people are missing the obvious solution:
Get a wind turbine in your back yard.
“Tempera paint or soap. Mark the outside of the window with soap or tempera paint, which is inexpensive and long lasting. ”
How is tempera paint or soap long lasting? Not everyone lives in the desert that is California.
I live in a rural area.
My house has a sun room that I use as a greenhouse.
We have sliding glass doors.
Birds hit our windows frequently. Starting early spring and continuing through to mid summer (July).
Most hit a window because they believe they are being taunted by another bird and they hit the window trying to attack their opponent.
All of the windows have near branches on which they can perch and study their opponent.
Some of the bluebird males repeatedly attack the window from shortly after dawn till the sun passes behind the local treeline.
I have watched pigeons attack windows exactly the same way, only from inside a tall office building. Only they mostly flare their feathers and peck at their reflection while standing on a window ledge
Over thirty years we’ve had a few fatalities; a grackle, a hummingbird and a Carolina wren.
The hummingbird was chasing an opponent and didn’t turn as fast as the hummingbird he was chasing. That bird made a solid hit on the window and was dead when we opened the sliding door. We had been watching hummingbird antics from our dining room table just inside of the window.
We also have had red shouldered hawks eating an occasional songbird and non-songbirds in our backyard. The red shouldered hawks nest in our woods and we hear their whistle shriek most of the year, but especially when their ravenous young are out and about.
One morning, I watched the hawk finish devouring a dove on top of my bird feeder, then later ate a goldfinch.
What I’m trying to say, I suspect the grackle and the wren were possibly trying to escape the hawk. Red shouldered hawks are amazing woodland flyers.
When urbanites start estimating from rough estimates from unscientific surveys and abjectly sparse real data. Along with their imagination regarding possible means of bird extermination gives real meaning towards GIGO..
Their estimates ain’t worth using, for any purpose.
As far as I know, all of the large bird watching/conservation organizations bemoan wind turbine bird slaughterhouses as they make irrational claims about cats, birds and windows.
The trouble with hawks, dogs or cats eating wild birds is that they do not eat feathers. Which always leaves a pile of feathers.
Once while fishing I spotted a pile of feathers and two wings from an owl as I walked the path. From the prints, I think a fisher caught an owl that was snacking on a mouse.
The scene contained a pile of feathers and feathers don’t degrade rapidly.
My cat has brought me many mice and voles, a couple of rabbits, a squirrel and the Carolina wren already mentioned. He apparently collected it from the window where we had already seen the dead bird.
Unlike the rabbit and squirrel body parts, our cat wanted nothing more of the wren.
Several times while hiking or hunting, I’ve come across fox dens. Easy to spot because there are usually lots of bones and feathers near the den entrance.
We also have black snakes (a type of rat snake) and they do eat birds feathers and all. No feathers left behind. Owls also eat a fair amount of feathers and fur. The owl pellets found below their vantage spots show bits of feathers, fur and bones.
If food is abundant, birds will be abundant.
Our woods, hills and mountains used to have many very effective and efficient hunters, wild cats; the lynx, bobcat and puma.
Other areas of North America has other species of wild cats.
Prey populations boom, predators boom; prey populations collapse, predator populations collapse. It is a very natural order.
I’ll tell you what.
Every fall, grackle and blackbirds flock together in enormous numbers all along the East Coast of America. Flocks that spend significant time wheeling, landing, flying, circling heavily windowed high rises and office buildings in the urban areas.
These flocks swirl around very close to the windows frequently.
When the bird organizations can actually tell us definitively how many birds are in the flocks; how many chicks were hatched, raised and joined that year’s flock; exactly how many birds died at each and every building from every flock all demonstrated by hard evidence; then I will consider their evidence seriously.
A couple of small birds will have up to three clutches a year contrainng 3-4 nestlings. They will do this for perhaps 3 years.
So each breeding pair will produce at least 25 nestlings.
Of whom 23 will have to die to maintain a stable bird population.
That is a 92% death rate. Of which some may fly into windows, and some may get found by cats, but the majority will starve. Or have heart attacks. Or freeze. And then be found by cats.
Birds will expand to fill the food supply. It’s that simple. Only top tier predators are in danger of hilltop bird mincers.
Ah, estimates… Going by the numbers in this study (the median kill rate, actually) – my house should be killing an average of a bit more than 3 birds every year. No window treatments, and the wife has feeders and bird baths scattered around the yards, both back and front, so probably we should have more than “our share” of kills.
Data.. In the 25+ years we have lived here, I have picked up a TOTAL of four dead birds after they thumped into one of our windows. ZERO in the last year (a pigeon did whack into the living room window – but when I was called out to dispose of it, it was already waking up from its unplanned nap, and flew off after a couple of minutes wobbling around).
Kills of feral birds by feral cats – yep, lots of those. Also a lot of kills of feral (and domestic) cats by feral canines. It’s called something like “the circle of life.”
As far as windows: would the regular old 8 x 11 residential-type window frames do some good? If so, seems it could be adapted to both plate glass on residences and not-so-high office-style buildings.
In ten years I have not found a single dead bird from window collision. One pretty little thing did hit the window and fell to a table below. Before I could take a picture it shook itself awake and happily flew away.
Perhaps the double glazing that is usual in this part of the world is a factor, Perhaps an abundance of trees for cover is a factor. There is certainly no lack of birds.
The birds seem to be pretty adept at avoiding cat predation and even seem to tease a cat by staying at a barely safe distance. The poor cats have much better luck catching mice. They earn my gratitude and a piece of dry loose dirt in my yard for their exclusive use.
Birds, as well as thieving deer, are encouraged by well stocked feeders at my neighbors and the many fruit trees and berry bushes at my place.
Only the most careless birds are occasionally caught. An example are the cedar waxwings which seem exceptionally careless, but are far from being endangered. They show up by the thousands at different times of the year to strip leftover fruit from the trees. They also seem to know when their favorites are ripening. They beat me to most of them. Cats will wait beneath the berry bushes and snag an occasional victim.
From my experience at least, the birds face very little threat from either cats or windows.