Dead Birds Falling from Cold Events

from Jim Steele’s What’s natural? column

Published in Battle Born Media October 28, 2020 

On October 8th a resident of Pacifica California reported that 2 birds fell dead from the sky onto his deck. That would startle anyone and raised grave concerns. People began suggesting possible causes: a mid-air collision, West Nile virus, rat poison, wildfire smoke, and of course the climate crisis. Some pointed out they had found a dead bird in their yard. Others referenced a massive die-off of migrating birds in early September over Colorado and New Mexico suggesting thousands, maybe a million birds had died. The speculated cause of death was wildfire smoke, starvation and a cold snap that dropped temperatures from 90°F to near freezing in a matter of hours. Sky-is-falling fears and fearing a “ bird flockalypse” one person wrote, “if birds are dying, we humans are next”.

Good scientists must examine all likely factors. So, I investigated the stories behind most documented bird die-offs.  For the case of a single dead bird found in someone’s yard, that bird may have died from disease, flown into a window, or simply died of old age. Most of our sparrows, warblers and hummingbirds don’t live longer than 13 years. Twenty-five to fifty percent of young birds die in their first year.

California asks people who find dead birds to report them to local vector control agencies so the birds can be tested for disease, West Nile Virus in particular. For the year 2020, to date about 5200 dead birds have been reported in California, a fourth of which were tested. Only 320 have had the virus, while most died of unknown causes. (Mass die-off of 10 or more birds are not included in their reports.) Los Angeles county reports the most dead birds, while rural Sierra County reports none. That suggests higher population centers with more eyes find more dead birds.

In contrast, the die-off of hundreds and thousands of birds, often during migration requires very different explanations. Good scientists must place such unusual events into a historical context. Was the September 2020 die-off in the southwest so historically rare that we can attribute it to how humans have recently altered our environment? Or, are such die-offs relatively common occurrences. Scientists calculate millions of birds die each year during migration in North America. We just don’t know all the causes, or what percentage of dead birds are actually observed.

2007 scientific paper reviewed reported bird die-offs across the globe and major die-offs were observed more than once a decade for the past 120 years. Some happen during spring or fall migration, other die-offs happen while on the breeding grounds. Most are associated with cold weather. On New Year’s Eve night in 2011, people reported dead black birds “raining” from the sky around an Arkansas town. People blamed everything from secret military testing and UFOs to bad weather. Investigations later determined 5000+ birds had died from blunt force trauma, which confirmed reports that birds were flying into buildings and towers. Apparently, someone attempted to scare away a roost of a million black birds, which are agricultural pests, with fireworks. Black birds have poor night vision which explains their collisions with houses.

The most common cause of other cases of bird deaths was bad weather – heavy rains, cold or snow. For example, a sudden cold spell across southern Germany, Austria and Hungary caused birds numbed by the cold to fall from the sky. Residents eagerly brought still living birds inside to warm, then loaded 89,000 birds onto planes and trains, sending them south to a warmer Venice, from which birds continued their migration.

In March 1904, a small town in Minnesota reported dead birds falling. Investigations determined nearly a million birds, all Lapland Longspurs, died during a heavy rainstorm. Over 750,000 birds were counted on just 2 small lakes that were still covered with winter ice. Autopsies determined most birds died from blunt force trauma as birds crashed into the ice or buildings.

Migratory deaths of thousands of birds this September in southwest USA likewise, appear to be driven by a cold snap. USGS experts have indeed told me that the best explanation is still a sudden cold snap that dropped temperatures from the 90s to near 30 F, killing birds already stressed by the rigors of migration. My analysis of archived EPA air quality doesn’t suggest smoke particulates coincided with that die-off, but officials have not yet ruled out wildfire smoke. Corpses are still being autopsied and whether or not there is lung damage could implicate wildfire smoke. 

I suspect the most likely cause of 2 birds falling dead from the sky in Pacifica was due to exhaustion from flying out over the ocean and trying to return to land. I have been on pelagic bird trips miles from shore where exhausted land birds flop down on our boat. Several studies have been performed on the Farallon Islands which are 26 miles offshore due west of Pacifica. Several studies note weather conditions, such as offshore winds that we naturally experience this time of year (i.e. Diablo Winds that also spread human ignited fires), cause birds to veer off course and fly out to sea. Many of the birds having arrived on the Farallons are later observed to be headed back to shore, suggesting they are guided to our coast if they can see land when not obscured by fog. Furthermore, most of the Farallon birds are young birds born that summer and typically less efficient at finding food and more likely to become emaciated after an extended overseas flight.

Of course as for all tragedies, media like the Guardian always blame the “climate crisis”, and downplay cold weather.  They push flockalyptic fears even though there is no support to suggest the sky-is-falling or ecosystems are collapsing. Birds have indeed suffered from loss of habitat, overhunting and window crashes. Fortunately, people are working to change that. I removed my bird feeder because it attracted birds that flew into my windows. But it is natural weather events that have caused most major die-offs. And yet birds have risked bad weather events for thousands of years in order to enjoy the benefits of migration.

Jim Steele is director emeritus of the Sierra Nevada Field Campus, SFSU and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism.

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October 28, 2020 6:37 pm

One large cause of bird fatalities which does not need deep investigation is wind-turbine rotation. If you stand near a turbine long enough you will see a mounting toll as the fast moving blades chomp into hapless birds. We could easily stop this tragedy.

mario lento
October 28, 2020 6:48 pm

I always thought it was lack of food, not cold or snow itself, that affected where birds went. Cold? Not so much.

Mark A Luhman
Reply to  mario lento
October 28, 2020 10:17 pm

“I always thought it was lack of food, not cold or snow itself, that affected where birds went. Cold? Not so much.” EXCUSE ME! what often bring on the lack of food it the cold that brought on the snow, that covered the food. Now again how is it not the cold or snow?

Christopher Chantrill
October 28, 2020 7:17 pm

If the average pair of birds are having one clutch a year and one chick survives the year, that is still thirteen chicks in a lifetime. Obviously almost all of those chicks are going to be dying of something other than old age.

And don’t blame the whole thing on climate. Whatabout eevil crows that love little chicks for lunch?

Clyde Spencer
October 28, 2020 7:25 pm

This is only anecdotal. I have a cousin in Custer (SD) that told me last week that she recently observed what turned out to be a cormorant, fall from the sky into the snow. It was still alive and was able to fend off her dogs until she was able to rescue it. She apparently got a nasty bite from the bird for her efforts. She turned it over to a bird rescue group. I was surprised to hear that there were cormorants in her area, but apparently there is a lake nearby that supports a colony. It has been unseasonably cold in South Dakota recently.

Mark A Luhman
Reply to  Clyde Spencer
October 28, 2020 10:22 pm

EXCUSE ME! Cormorants are and evasive spices in the US ands they are everywhere. They do great damage to fish populations and chase out and eliminate native birds from the ecosystem. Have you ever been in the Dakotas and Minnesota?

Reply to  Mark A Luhman
October 29, 2020 4:21 am

They are indeed a difficult spice to acquire, but if you look hard enough… delicious! Just kidding, another auto-correct victim i presume. They certainly can be a pest. The province of Ontario, Canada had a season for them this fall in efforts to reduce the population.

Loren C Wilson
Reply to  Mark A Luhman
October 29, 2020 6:29 am

An invasive species is just nature operating on the law of the survival of the fittest. We humans accidentally and sometimes on purpose introduce non-native species, but this happens naturally all the time. Natural populations and ranges are not any more static that the weather. Should we interfere with the cormorants finding a better food source?

Clyde Spencer
Reply to  Mark A Luhman
October 29, 2020 9:17 am

Now, if you were both a betting man, and a thinking man, what do you suppose the odds would be that, if I have a cousin living in South Dakota that I communicate with, I have been in the “Dakotas?”

BTW, unlike Minnesota, the Black Hills aren’t really known for their lakes.

October 28, 2020 8:59 pm

Bird cope ok with heat so long as they can access water.

I have a bird bath out the front .. birds love it in Summer.

Cold, harder to cope with.

Reply to  fred250
October 29, 2020 9:10 am

A brother had a hummingbird provide a show for guests, with his cascading fountain (round large trays spaced apart, water fed into top).

Bird took drinks of water, then spent time splashing water on itself.

I don’t know if he had turned it on before guests arrived. Hummingbirds here hide in ‘cedar’ hedges.

Bob in Castlemaine
October 28, 2020 9:05 pm

Not just cold but heat has also been known to kill birds in their thousands:
“Heatwave kills thousands of birds — this was climate change in 1932”
And back in 1896 heat was the culprit too:

Joel O'Bryan
October 28, 2020 9:15 pm

Breaking Note from 66 Million years ago: Chicxulub meteorite dust Global Winter k1lls even feathered dinosaurs on opposite side of planet from impact site.

October 28, 2020 9:47 pm

I read somewhere that out of a brood of four American Robins, only one chick is likely to survive and breed. However, in favorable locales Robins may produce three broods in a summer.

Mark A Luhman
Reply to  brians356
October 28, 2020 10:26 pm

And a late snow storm can eliminate all of them of a large area in the north. Where I grew up the male start to show up late February even though snow can some in May something that did not happen in my childhood.

Wim Röst
Reply to  Mark A Luhman
October 30, 2020 3:37 am

The more hostile the environment (by predators and/or natural variability) the larger the offspring.

“Typically, elephants only give birth to one calf at a time, although twins do sometimes occur. In her lifetime (elephants can live for up to 70 years in the wild!), a female elephant can give birth to as many as 12 calves”

“Mature eggs make up a large portion (20%+) of the female’s body weight. The fecundity of herring females is typically in the range of 20,000-50,000 eggs per female, although a large female herring can lay as many as 200,000 eggs.”

October 29, 2020 12:57 am

tens of thousands of birds in the US also die every year from hitting tall buildings, confused by lights.

(The 9/11 memorial light beams are switched off when met radar suggests large numbers of migrating birds in the vicinity).

There is a great deal of evidence that the fires were related to this years die off: and this is a shabby piece of reporting, trying to somehow hide/excuse/divert from that possibility.

Carl Friis-Hansen
Reply to  griff
October 29, 2020 3:42 am

Griff, as the author indicate, it is too early to know if the wildfires had a significant impact:

My analysis of archived EPA air quality doesn’t suggest smoke particulates coincided with that die-off, but officials have not yet ruled out wildfire smoke. Corpses are still being autopsied and whether or not there is lung damage could implicate wildfire smoke.

Next time please read the whole article before judgement.

Jerry Palmer
Reply to  griff
October 29, 2020 5:44 am

“There is a great deal of evidence that the fires were related to this years die off”

Would that be naturally ignited fires, or the fires started by your arsonist friends?

Reply to  griff
October 29, 2020 9:20 am

“There is a great deal of evidence ……”

Provide references of this evidence please.

From “peer reviewed” scientific publications. You warmists only approve of the use of that process.

Since most publications appear to be largely under warmist/leftist control, providing such references should not be a problem.

October 29, 2020 1:08 am

Birds can get caught up in atmospheric events and carried so high they freeze to death or fly into a strong headwind making no progress until they die of exhaustion. In mass dense flocks some die from collision – birds in the middle can’t see approaching objects and have limited room for manoeuvre. In the UK recently hundreds of Starlings died after a murmuration slammed into a road as the ones at the bottom had nowhere to go – perhaps the flock was spooked by a raptor up top.

J Savage
Reply to  MrGrimNasty
October 29, 2020 6:02 am

The YouTube channel “Smarter Every Day” has a fascinating episode that deals with how murmurations form if you are interested. He shows how the complex behavior can be simulated on a computer with just a few simple rules.

Janice Moore
Reply to  J Savage
October 29, 2020 5:12 pm

Thanks for the tip, J 🙂

The Boids Algorithm (yep, that name is apparently based on a New Yawkuh’s pronunciation of “birds”) is presented here at Ben Eater’s site:

That page also contains a link to “Smarter Every Day’s” youtube video about bird murmuration.

Very cool!



THANK YOU, JIM STEELE, for another great article. Fun to learn about “how things work. ” From a bona fide scientist (i.e., one who bases his conclusions on observations).

(still praying for you, dear Mr. Steele, every day – hope you are doing well)

Carl Friis-Hansen
October 29, 2020 1:20 am

I suspect the most likely cause of 2 birds falling dead from the sky in Pacifica was due to exhaustion from flying out over the ocean and trying to return to land.

Around 1960 while living on a small island called Hesselø in Denmark, a big white bird made an emergency landing in front of our house. The bird was exhausted and could not takeoff again.
After five days in our warm kitchen, the bird was put outside the house again. After a few minutes of adjustment, the bird took off and continued its migration to north east Scandinavia.

My parents diagnose was the same as Charles Rotter’s, migration is hard, you eventually get exhausted, see an island in the middle of the vast sea and make an emergency landing in the last moment.

Peter Morris
October 29, 2020 5:14 am

Huh. Adds another dimension to the term “bird brain.”

As always, thanks for the calm, rational post, Mr. Steele.

October 29, 2020 5:29 am

Flying into windows is the reason I do not have bird feeders attached to my little house. That, and the mess they make, will attract ants and I have no desire to have ANTS in my house. Period.

I put bird food on the railing around my front steps (8×10 deck) and they do quite well that way as it gives me room to spread out the food and room for them to gather without crowding. It works quite well, even though they spill a lot of it. It also attracts pregnant squirrels, but that’s the penalty you pay.

My two saddest sights were a very old cardinal, so old his facial mask was thinning out, and I was his only food source. He would come right to the railing when he saw me, but after three years, he didn’t come any more. The other one was a small bird, looked like some kind of warbler, that glided into my yard and into the snow and stopped there. Died in mid-flight, and I was putting out plenty of food at the time. I’ve had everything from southbound goldfinches to female red-bellied woodpeckers and sparrows that a rare around here show up for dinner. Lots of photos.

I had 22 cowbirds show up for a meal for a few days.

I’ll be doing th4 same thing here this winter, but I know that some of them will be having their last meal and while it makes me sad, it’s Nature’s way.

Abolition Man
October 29, 2020 7:46 am

Thank you to Jim and Charles for this post!
As a lifelong nature lover and avid birder, I have numerous feeders strategically located around my house! Most of my 14 or 15 hummingbird feeders are already cleaned and put away for the winter as the last hummer I saw on 10/24 was hopefully long gone before our current winter storm arrived Monday night. I can look forward to a break from cooking up one or two gallons of nectar every day until they return next May!
In the meantime I keep two quail blocks, and several bird baths, out for my favorite seed feeding birds; the thrashers, towhees and dark-eyed juncos that keep me company over the winter.
I was deeply saddened by the die-off that occurred back in September when an unusually cold weather front moved through my area just as the fledgling swallows were learning to fly in preparation for their journey south. There were dozens of swallows resting on the pavement of the cul-de-sac; trying get some warmth from the macadam and apparently too tired or weak to fly. I went to take a closer look and found that they were all young birds (violet-green swallows, I believe) with an adult that flew off when I got too close. Trying to figure out what was happening, I picked up several of the birds to see if there were any signs of injury or trauma visible. They seemed uninjured and happy to remain in my hands for the warmth there. Without any recourse that came to mind, I put them back down in spots that would get the most sunlight without being in the way of traffic. The best theory that I could come up with was that they were being affected by the cold and hunger from much of their insect food being killed or driven off by the weather. Sadly, many of them did not survive.
At the same time I noted in my hummingbird journal that the hummers were crowding around the feeders; hardly flying at all, while they spent most of the day loading up on calories to stave off the cold. I had to make two gallons of nectar that day and refilled most my feeders to keep up with them! Hopefully, by next summer I will have a little green house put up for my tomatoes where a cold and tired, feathered traveler can rest up and regain their strength.

Steve Z
October 29, 2020 8:57 am

There are many causes of death for birds, very few of which have anything to do with climate change.

When I was in college, the four-story library building had large window panes on the entire east wall, and the grating for the air intake for the ventilation system was below, which caused a downdraft in front of the windows when the heating or air-conditioning system for the library was running. Every day for about two years there would be several new dead birds found on the grating.

Apparently, some birds saw the reflection of the sky in the windows, and thought it was a safe place to fly, then got caught in the downdraft and crashed into the grating. During the spring of my sophomore year, someone got the bright idea of taping pictures of flying hawks (facing outdoors) to the inside of the library windows, in order to scare off the smaller birds, and the number of dead birds decreased dramatically.

Birds can die of many causes. But if, as mentioned in the article, a sparrow might live 13 years, and a mating pair might hatch three or more chicks per year, then a mating pair could produce 36 offspring to replace the parents. At that rate, the world will never run out of sparrows, even if some of them get frozen or blown out of the sky, or crash into immovable objects.

October 29, 2020 9:12 am

Weather may be a worse problem for butterflies, such as the Monarch ones that eco-alarmists flap about.

Majority of them migrate across the US into Mexico.

A primary reason for fluctuation in population.

(There’s a lesser route along the west coast that may be safer, IIRC those Monarchs winter in SoCal.)

Gary Pearse
October 29, 2020 10:07 am

I was in Edmonton, Alberta in January in the mid 1970s on a federal government trip when the temperature dropped below -50C – a new record during the depths of the “Ice Age Cometh” period 1944 -1980. Pigeons frozen to death, many during flight in a particular morning were scattered all over downtown. If birds are dead in large numbers in very cold weather you don’t need to look too far for a reason. Especially tough customers like the city pigeon. I looked for a link in vain, but there is no doubt about the story. It should be available in archived Edmonton news stories.

Reply to  Gary Pearse
October 29, 2020 2:42 pm

Gary Pearse says :

If birds are dead in large numbers in very cold weather you don’t need to look too far for a reason.

Yes, the Windmill farms aren’t to hard to spot.
They aren’t called “bird-blenders for nothing.

Janice Moore
Reply to  Gary Pearse
October 29, 2020 5:46 pm

Hi, Gary,

I tried and tried to find a pigeons-freeze-in-Edmonton news report from the 1970’s. Nothing. 🙁

I did find this item, though:

The record for most consecutive days below freezing set in 1974 wasn’t broken until…..2018 <– CO2 UP. WARMING NOT.

GAME OVER, solar scammers (and Big Wind and electric-vehicle-market-share-by-fiat, etc al.).

I am sorry I didn't find what you hoped for. Hope this is of use. I very much wanted to do something for you who I will never forget for that wonderful thing you said (not to me, personally) about "the world [for a man in his 50's or 60's and up] becomes full of beautiful women. "

I needed that, so badly, at that time……still do (so, you are blessing me for the rest of my life). 🙂

Thank you. Again. 🙂

Gratefully yours,


Tim Spence
October 29, 2020 10:50 am

I’ve heard of swallows falling out of the sky, frozen solid.
I’m also hearing recently of Leonardo Vultures falling from the sky with West Nile virus being identified as the cause.
The vortex from A380’s might be another problem, I heard of a jet being turned upside down 7 miles behind the A380. Imagine what that vortex might do to a flock of birds.

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