This is another study that has hit the news, this time scaring people with the idea that the whole of the US may lose all its birds rapidly in the near future.

Short summary - studies like this are hard to do and the 3 billion figure should be treated cautiously - there can be observer effects. If accurate, the reductions are mainly in the most common birds, and some of them nuisance species such as the starlings. There is no possibility of the most common birds in the US going extinct.

We have had several reports published recently that got lots of media attention that were low quality such as that insects study: New research does NOT mean a world without insects. Or the research may later turn out to be flawed, such as the case of the Costa Rica insects study which didn't take account of the effect of a hurricane. See OOPS - Purto Rican insects in the forest canopy increase with warmth - not decline - and frogs like the warmth too. The journalists also often misunderstand or exaggerate, see: Great tits do NOT risk extinction from climate change - are of least concern and increasing - what did the paper really say?

This shows that all the media attention does not mean it is definitive or correct.

So what are we to make of this paper? Has it been reported correctly, and how much weight should we put on the conclusions?

It is a study of North American birds, based on a review of published bird counts going back to 1970, together with an interesting attempt to use radar data to count populations of nocturnal migrating birds over the last decade. Apart from the radar studies they did not do any direct data collection or data reduction themselves. These are amongst the best ways to count populations of birds we have but there are still many many known issues with bird counts.

Then, of the 3 billion reduction, 1.6 billion are from the ten most common species. 0.4 billion are from the nuisance invasive species, the house sparrow (0.33 billion) and European Starling (0.083 billion).. There are programs to reduce their numbers.

Others are birds that expanded over the US before the 1970s, as humans spread across the Americas cutting down forests and natural habitats. Some of the decline, if it is a real decline, may be due to species that had an artificial increase, and are now returning to earlier levels as habitats are restored.

Then the lists also include some bird species have increased markedly since the 1970s, especially the raptors. This is not necessarily always a conseration success. For raptors, the period starts with an artificial low in the 1970s due to the DDT poisoning of their eggs making the shells thinner.

For another possible bias, most of this study is based on population counts for species rather than an attempt to count all the birds in a region. But this makes it incomplete. They only have numbers for 76% of the US bird species.. They know nothing about the other remaining quarter (24%) of species that they leave out.

Given that 1.6 billion of the decrease came from just ten bird species, it's possible that increases from some of the many species they did not count may impact on the figures significantly.

Then, much of the attention has been on their extinction argument - which hardly really counts as an argument at all. It was just an argument by pathos based on the vivid image of the extinction of the passenger pigeon, not based on any actual risk of extinction of the most populous species of birds in the US.

The paper is here:

This is another article I'm writing to support people we help in the Facebook Doomsday Debunked group, that find us because they get scared, sometimes to the point of feeling suicidal about it, by such stories. Do share this with your friends if you find it useful, as they may be panicking too.

THEIR EXTINCTION “ARGUMENT”

This is one of the main things scaring people, even though it is hardly the main point in the paper. It is picked up e.g. in CNN and especially in the New York Times article which is rather scary with a very scary and inaccurate title (for anyone reading it in a panicked state of mind)

Though they do not say this in the article, one of the researchers is quoted by the NY Times as saying

“It’s not just these highly threatened birds that we’re afraid are going to go on the endangered species list,” he said. “It’s across the board.”

In the paper, they use the example of the US passenger pigeon to motivate the idea that very common birds like these can go extinct. They give no other reason to suggest a drop in numbers of very common birds could lead to extinction, Surely the most common birds in the US are not listed as at risk in the IUCN red list?

This immediately seems a bizarre argument - after all the passenger pigeon went extinct before we had any laws at all to protect birds. The first laws were put into place after this event which was a huge wake-up call.

Since this is the only reason they give, let’s look at it more closely. I will highlight this passage as it is the suggestion of the authors that common birds in the US could face extinction that is most scaring the people I’m helping.

This is all they say:

Extinction of the Passenger Pigeon (Ectopistes migrato-rius), once likely the most numerous bird on the planet, provides a poignant reminder that even abundant species can go extinct rapidly.

That is an argument by emotion, pathos, not by logic or reasoning, logos with the “poignant reminder”.

Passenger pigeons became extinct because of determined hunting even as the numbers got lower and lower they caught vast numbers of them at once and they were very easy to catch. They moved around in large flocks, and this was just after introduction of the railroads making it easy for hunters to race around the US whenever a flock was reported to kill them all and they also killed the young in nesting season time. Just killing everything they found and putting them in barrels. The early days of environmentalism came too late.They could easily have saved it at any point, but just went on killing them faster and faster, the fewer there were left for all the hunters to find.

(click to watch on Youtube)

As they say there, there were no attempts to protect it. It is only after the passenger pigeon went extinct that the first legal protections for migratory birds were put in place.

Even as the pigeons’ numbers crashed, “there was virtually no effort to save them,” says Joel Greenberg, a research associate with Chicago’s Peggy Notebaert Nature Museum and the Field Museum. “People just slaughtered them more intensely. They killed them until the very end.”

Why the Passenger Pigeon Went Extinct - and whether it can, and should, be brought back to life a century after it disappeared.

This is not a situation that we will ever duplicate today with any species and it is a bizarre analogy to use to me. Well as I say it works emotionally, you think about the passenger pigeon and how it was lost so easily, you get upset and then emotionally you feel that a reduction in population now is similar to what happened to the passenger pigeons and can easily start feeling it could happen again.

But logically it does not follow at all because it is such a different situation. I'm a little surprised to see such forceful use of pathos with no supporting logos survive peer review into an academic journal.

THE PASSENGER PIGEON COULD EASILY HAVE BEEN SAVED FROM EXTINCTION IF ANYONE HAD GIVEN IT ANY THOUGHT AT THE TIME

That passage continues:

Systematic monitoring and attention paid to population declines could have alerted society to its pending extinction. Today, monitoring data suggest that avian declines will likely continue without targeted conservation action, triggering additional endangered species listings at tremendous financial and social cost.

Back at the time of the passenger pigeon, they wouldn’t have needed systematic monitoring. It would not have been hard to notice that there were no longer flocks of millions of passenger pigeons flying by.

The pigeon is one of the easier aimals to keep in captivity. The banded tail pigeon is a breed of pigeon that is so close to the passenger pigeon genetically that there is a proposal to try to restore the passenger pigeon by tinkering with the genes of the band tailed pigeon (not so easy for a bird though, because of the way the eggs form, so far nobody has succeeded in cloning any bird).

Anyway the band tailed pigeon is kept as a pet worldwide

File:Patagioenas fasciata -San Luis Obispo, California, USA-8 (1).jpg Band-tailed pigeon - Wikipedia

Bird fans have discovered there is much to admire in this lovely little species. The Band-tailed is just one of several breeds of pigeon that are kept domestically around the globe. Many people are finding Band-tailed Pigeons can make a great addition to the home.

Band-tailed Pigeon

Probably all that was needed was for one bird fancier to decide to keep a small flock of a dozen or so passenger pigeons as pets and they would have saved the species.

“Oh, it looks as if the passenger pigeon is going extinct - there are far fewer than there were when I was a kid - what if I keep a few of them as pets to save the passenger pigeon from extinction?”

Well actually that did happen, after a fashion. A few were kept in captivity by Otis Whitman, who got them from David Whitaker. He in turn got a pair of young birds from a young Indian who trapped them in Shawano County in Northeastern Wisconsin.

Otis Whitman bought the entire flock of 15 birds by 1897. There were nine young, only four lived leaving nineteen, and he returned seven. Many more eggs were laid but only two young survived, in 1898. At that point he had 14 and presumably Whitaker had seven making the total 21. But they then had no more young and died one by one.

Details here

This shows they could breed in captivity - but they eventually stopped breeding. The species was highly gregarious and needed large flocks for optimal breeding conditions.

The paper ends:

History shows that conservation action and legislation works. Our results signal an urgent need to address the ongoing threats of habitat loss, agricultural intensification, coastal disturbance, and direct anthropogenic mortality, all exacerbated by climate change, to avert continued biodiversity loss and potential collapse of the continental avifauna. (emphasis mine)

There is no attempt at logical reasoning here and the passage is not cited to anyone else for more details. Why didn’t a reviewer red line this and say “supporting evidence needed?”

Also the paper does not go into the causes of the declines in population, if they are indeed population declines.

They do not cite the IUCN red list and they don’t have anything there to tie reductions in the populations of very common birds to any reasoning as to why they would then risk extinction.

If you dismiss the passenger pigeon argument, which is just use of pathos, there is no substance here.

BIRDS NOT ESPECIALLY LIKELY TO BECOME ENDANGERED

The vast majority of bird species are of “least concern” - the green bar in this summary chart from the IUCN red list:

Species assessed as Extinct in the Wild (Black, EW), Critically Endangered (Red, CR), Endangered (Orange, EN), Vulnerable (yellow, VU) Data Deficient (gray, DD), Near Threatened (lime green, NT) and Least Concern (green, LC).Summary Statistics from The IUCN Red List of Threatened Species

For more on this, see my section in the article ont he IPBES report:

However many in the US are at risk. This is not using the same criteria so you can’t do a direct comparision, but a study in 2016 found that 432 of the 1,154 native bird species found in the continental United States, Canada and Mexico are “at a risk of extinction without significant action.”

Species Assessment Summary and Watch List

Here's a List of Every At-Risk Bird Species in North America (All 432 of Them)

However, this leaves the remaining 722 species as not at risk at all. Common birds with millions of adults are not likely to be in these lists.

THESE PAPERS ARE PART OF A SCIENTIFIC DIALOG AND WE SHOULDN’T EXPECT TOO MUCH OF THEM

That extinction argument is quite strange to my eyes. But it’s mainly the media attention that’s brought a somewhat odd unsourced paragraph in a paper into a definitive statement being shared around the world.

Papers like this are part of a scientific dialog. Scientists have to be permitted to write papers that are done to the best of their ability but may lead to controversial conclusions, be based on limited data etc. They need to be able to make mistakes, and learn from them.

Peer review normally finds things like this, but you sometimes get strange things slip through peer review. That’s hardly a big deal either.

But nowadays any such study is immediately published in the mainstream media as a major new result and shared virally around the world. When that happens a paragraph that someone wrote without a great deal of thought, not the main point of the study, suddenl becomes what everyone talks about as if it was a conclusion from a conference of hundreds of scientists coming together to make a systematic high level review of the evidence from thousands of papers.

Others that come to less dramatic conclusions are ignored. Who pays any attention to the updates of the UK bird population counts that come to the conclusion that our bird population has hardly changed for decades?

WHAT DID THEY FIND?

First, it is based on a list of species they look at only - not birds generally apart from the radar counts. They relied on previously published bird counts, e.g. from the Audobon regular bird counts by enthusiasts.

They based it on 76% of the bird species of the US.

We evaluated population change for 529 species of birds in the continental United States and Canada (76% of breeding species)

They would not spot a major increase in any of the remaining 24% of US bird species which could easily fill the gaps and make the numbers the same - especially some previously uncommon bird that became common or indeed maybe many such, like the parrots.

2.5 billion of those 3 billion lost (if the survey is right) are from four types of bird:

  • New world sparrows (-38%) - 38 species
  • New world warblers (-37.6%) - 44 species
  • New world blackbirds (-44.2%) - 18 species
  • Old World sparrows (-81.1%) - 2 species

For details see the Supplementary data.

Some birds however increased hugely

  • > 1000% for parrots
  • 988.6% for Boobies
  • 914.5% for cranes
  • 810.4% for Pelicans
  • 332.8% for Ibises and Spoonbills
  • 304.4% for Ospreys - these would be recovering after the crash in population due to effect of DDT on their eggs in the 1970s. Birds of North America Online
  • 265.3% for new world vultures

to pick out some of the more dramatic increases.

The parrots there are naturalized pet parrots.

Monk parakeets (naturalized escaped pet birds) which survive Chicago’s harsh winters by switching to foraging from backyard feeders - in the wild they feed exlusively in grassland (Image: Jennifer Uehling)

There are only two native species to the US, the Carolina parakeet which is now extinct, and the thick-billed parrot which is a Mexican bird that used to range into the US but was driven out of it.

The monk parakeets were imported from South America as pets in the 50s and 60s, and some escaped or were released. There are now 56 observed species of parrot in the wild in 43 US states and 25 of them are now breeding in the wild in the US.

Escaped pet parrots are now naturalized in 23 U.S. states

LOSS OF BIRDS FROM GRASSLAND

The biggest reduction is in grassland species. They cite a 2018 article on the topic, a separate more focused study - so that was no surprise.

It's mainly due to first of all pesticides, and also changing the timing of cutting the hay. Many grassland birds nests can be disturbed when the grass is cut by mowing (if you cut the grass early, you can destroy the nests of nesting birds) They can also be affected by pesticides.

The 2018 paper concludes:

Modifications to farmland management such as reducing pesticide inputs through integrated pest management and maintaining or restoring uncultivated field margins and native habitat could positively influence farmland birds without significantly reducing agricultural crop yields.

Analysis of trends and agricultural drivers of farmland bird declines in North America: A review

So, this is something you can do something about without any commercial impact with such things as field margins.

DRILLING DOWN INTO THE DATA - COMMENTS ON THE PAPER BY BRIAN MCGILL

If you drill down to individual data then four of the top losers are amongst the ten most abundant.

I will summarize some of the points made by Brian McGill, a macroecologist from teh Univesrity of Maine who studies how human-caused global change affects biodiversity and the global ecology, with a first look at the data.

He finds that the ten individual species with the biggest decline amount for 1.6 billion individuals, more than half the total. Some of these are huge reductions percentage wise as well, several with more than a 100% decline. The top decline is for the House Sparrow, a 356.5% loss. Also for the Blackpoll Warbler (514.9% loss).

The paper itself says

“While not optimized for species-level analysis, our model indicates 19 widespread and abundant landbirds (including 2 introduced species) each experienced population reductions of >50 million birds”.

The House Sparrow and European Starlings are actually invasive species that land managers wish to reduce in the US (they are abundant in other parts of the world, of least concern and they are not native to the US and are a nuisance species there).

Eight of those top ten are of least concern and the remaining two are “non threatened”. There is no way that any of them are actually at any risk of extinction at all.

Some of the ones with biggest losses, Savannah Sparrow, Horned Lark, Common Grackle, Red-winged Blackbird, and invasive House Sparrow and EuropeanStarling are all fond of low intensity farmlands. They were much less common before humans cleared much of North America for farmland. They are now declining again with intensive agriculture, but from an artificial high.

In some regions of the US experiencing reforestation, forest birds are gaining while the farmland birds are losing. So while I wouldn’t call it good news, this is hardly the most disastrous story out there. And these species may still be more abundant than they were before Europeans arrived even after large declines (and certainly are in the case of the two invasives). Its really a rather complex story.

He concludes:

So do the statistics in this study really directly address questions of conservation or biodiversity preservation? Not so much (at least not in the headlines). For that you need to go look at birds that are rare and declining. Of course that is what conservationists have been doing all along. And there you get a mixed story. Bald Eagles and Wild Turkeys have made pretty spectacular come backs. And the Kirtland Warbler and California Condor are both naturally rare but have actually increased in recent years due to intensive management efforts so fairly positive results but certainly not victory. But we have made several bird species go extinct including the Carolina Parakeet, Heath Hen, Passenger Pigeon, Labrador Duck and probably the Ivory Billed Woodpecker and a few more (many more if we include Hawaii). And a number of other species are on the ropes (a few dozen endangered bird species in North America, again a disproportionate fraction of them in Hawaii). That is a really important story (both the positive and the negative), but it is an almost wholly different story than -3,000,000,000 or -29%.

Did North America really lose 3 billion birds? What does it mean?

So, it is a complex story and no, there is no risk of common US birds vanishing from the skies of North America. There’s an interesting discussion by experts commenting on his blog post.

COULD IT BE DUE TO ISSUES WITH THE COUNTING METHODS?

Counting birds isn't easy. One way is to walk through a wood for instance and just count how many birds you see and then do that again every day - but different people may find it easier to spot them. It may be through trapping but the numbers vary depending on the behavioiur of the birds,

This graph shows what has happened to bird numbers in the UK tracking 180 different species, we are one of the better studied regions for birds, with lots of historical records.

Wild Bird Populations in the UK, 1970 to 2017

Checking the tables then the surveys are by various methods. E.g.

  • 25-mile roadside surveys with 50 3-minute point counts
  • Aerial surveys corrected for detectability with ground surveys

etc. It would depend on whether people today are counting the birds in the same way that they did forty seven years ago - how standardized the counting methods are.

It is possible to estimate numbers of birds - but the methods are not perfect. For instance in the UK many bird surveys are done by walking through forests and countryside. We have a right to roam in Scotland particularly - so you can walk anywhere even through private property so long as you respect privacy, and don’t disturb agricultural activities, deer or grouse shooting etc. So bird surveys in Scotland are often done by just walking through the fields or woods or hillsides counting birds.

You can’t do that in the US except in national parks. So most of it is based on counting by driving along a 25 mile section of road and stopping 50 times then counting how many birds you see or hear in the different species in three minutes, then moving on. Many factors can affect that. E.g. sometimes just doing the point count a half hour later in the morning can make a big difference to the number of birds. Doing it from roads will mean you over count birds that forage close to roads - e.g. ones attracted to roadside verges and undercount birds that avoid roads. You won’t count birds that prefer inaccessible areas with few roads.

Although one hopes that the sampled population is the same as the target population, often subareas within the original study area may not be accessible for a variety of reasons, such as private landowners forbidding access. Thus, these subareas are not available for surveying and hence are not part of the sampled population. Statistically based inferences cannot be validly extended to them. Other common examples are counts conducted along roads or trails so that other areas of interest have zero probability of being surveyed. Here the sampling frame would be composed only of roads or trails and their adjacent areas where birds have a nonzero probability of being sampled, but perhaps not detected, during the survey. Consequently, inferences cannot be properly made to bird populations beyond the surveyed area unless one is willing to assume areas on and adjacent to roads or trails support similar numbers of birds as those away from those features. This assumption seems questionable given that roads and trails are typically not placed randomly and factors affecting their adjacent habitat structure and composition may be expressed differently than in surrounding areas.

TOWARDS RELIABLE BIRD SURVEYS: ACCOUNTING FOR INDIVIDUALS PRESENT BUT NOT DETECTED

Another factor that they do not mention in that paper is that there are fewer birds near to roads, for whatever reason. Could some of the change in numbers be due to this? According to this study then it’s mainly due to birds being hit by cars

There has been a huge increase in the vehicle miles traveled from 1.8 million to 3.2 million from 1985 to 2015. Human casualties have not increased, so the roads are safer for humans, but are they safer for birds?

As I said in the intro, 89 to 340 million birds die of traffic collisions every year (U.S. Fish & Wildlife Service - Migratory Bird Program). I can’t find numbers for the numbers that died of traffic collisions in 1970. But from those figures it would be no surprise if it was much less.

The population of a species could be fine everywhere else yet hugely reduced near roads due to the increased traffic.

Also a trail with a lot of people walking along it will discourage birds from nesting close to the trail. Some shy birds especially are affected by this.

Then another factor, the time of day can make a difference. Some times of day can be very sensitive e.g. early morning, half an hour later or earlier can make a big difference to the bird count by bird call or flight.

Then you have many observer biases to bear in mind. For instance not spotting birds while you are writing down the results. One way to do that is a double count where one observer counts, the other writes down what the first observer says they saw and then adds any other birds that they saw.

Counting birds isn't easy. One way is to walk through a wood for instance and just count how many birds you see and then do that again every day - but different people may find it easier to spot them. They can also misidentify similar species, if they are less experienced. There are many other possible issues

You can do it through trapping but that also has biases and their counts were mostly using the point method.

There are many other issues with bird counts. They are used a lot but they are not perfect.

You have to work with imperfect data. That’s not the criticism here. But what I was missing in this paper was any discussion of whether the imperfect data due to the methods used could have accounted for some of the change.

I asked Brian McGill about this and he says:

I am very familiar with the Breeding Bird Survey (BBS) that was used to derive the trends. No survey is perfect. But the BBS is one of our best inventory and monitoring protocols anywhere in the world. It was setup by careful scientists to ask exactly these questions of relative abundance (which species are trending up or down, which species are more common or rare, what are overall trends). And it has been run for 48 years with thousands of routes. It has high quality observers and uses quality flags on runs. Any survey is going to have biases. And the road biases you mention is the most common critique of the BBS. But having walked some BBS routes I can say: a) some of those roads are dirt roads in national conservation lands, and b) roads are an ever present and growing feature of our landscape. But nobody has really shown in any quantitative fashion that I am aware that the BBS is systematically biased. There are some known biases of the BBS it doesn’t sample water birds or night-active birds well. But these are well known and taken into account (among other things there are some supplementary programs that survey these animals better).

Bottom line, I would bet a lot of money on the relative trends that come out of the BBS being accurate. I think decline in total number of birds in NA is real. I would put much less faith in the precision of assigning a 3,000,000,000 number to that. And I think looking overall it hides a lot of variability. As noted in another comment -6.6 billion loss and 3.3 billion gain is a lot of churn or turnover. So we need to understand that turnover. And we need to understand who is winning and who is losing (some of the losers I’m not so sad to see losing).

But losing a non-trivial chunk of our total birds is (as I’ve said several place on this page) is I think all too real.

EVIDENCE FROM RADAR

Their most convincing data is from radar - a network of weather radars that have been observing bird migrations since 2007 but it is only for ten years. It also only looks at birds that migrate at night.

This is based on a network of 143 radar stations:

This found a reduction in bird migration in the Eastern US but not southern or Pacific regions of the US.

They say that most of the nocturnal bird migration in Eastern US is of temperate forest (boreal) birds. There is no consistent trend in the other regions.

This is quite a strange passage in the article:

Reduction in biomass passage occurred across the eastern U.S., where migration is dominated by large numbers of temperate-and boreal-breeding songbirds; we observed no consistent trend in the Central or Pacific flyway regions. Two completely different and independent monitoring techniques thus signal major population loss across the continental avifauna

So, the radar survey finds a reduction in nocturnal migrating birds in Eastern US over 10 years and they use this as "independent verification" of wide ranging statements about birds declining in many habitats throughout the US from the 1970s.

It's only some fraction of the forest birds that migrate at all and of those only some migrate at night.

Another paper about radar observation of migrating birds covers 142 species of nocturnal migrants in Eastern US, and says that around 19% of extant birds migrate, it doesn't say what percentage migrate at night.

They found the birds by analysing the data from the radar by cloud computing and removing signals automatically that were due to precipitation. Quite a bit of their work is to do with various ways to remove false signals due to precipitation.

The data could include nocturnal insect migrations and nocturnal bat migrations but they estimate that only 2.1% was due to insects and they think the contribution from bats is small also.

It could also be affected by upgrades of the radar, they control for that.

There’s one thing they do not seem to cover. They counted them in the same period each year for the spring migration: 1 Mar – 1 July

Nocturnal migration is also affected by weather - less likely to fly during side or head winds and precipitation. It’s also afected by the timing of the food sources they forage on.

Amongst all the factors, the wind speed at migration altitudes is the strongest factor influencing how many migrate at any time. So - how much of the variation could be due to changing weather patterns and change in timing of the seasons and the food sources?

Also, it's only a reduction over 10 years, species can decline and recover it doesn't seem long enough to establish a trend especially not one to extrapolate forwards.

I think the radar section is the most convicing part of the paper, but it's still tricky analysis and you wonder if they could have missed something e.g. somehow not removing all the precipitation properly, or not accounted for influences of changing of season or wind patterns.

BIRD DEATHS DUE TO CATS FAR OUTNUMBER BIRD DEATHS FROM GRASSLAND MANAGEMENT

Meanwhile, if you look at the number of bird deaths due to human influence, then the domestic and feral cat kills far more birds than agricultural practices.

Of course this doesn’t count changes in numbers due to changing habitat.

However, cats do kill far more birds than agriculture and they do preferentially kill the types of birds they saw in decline, the forest birds. They do not do any analysis of the causes. Probably cats should be looked at as one possible factor.

The number of domestic cats in the US has tripled from 30 million to 90 million during their study period:

From: What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al

I am not saying that this is the reason. Correlation does not mean causation. But it does seem to be something worth investigating.

Just as you have a lower population near roads because of the traffic killing birds, then you may have a lower population due to cats killing birds.

Cats are responsible for the vast majority of all bird killing due to human influences. Domestic cats have been responsible for making 63 species extinct in the last 500 years - 40 birds, 21 mammals and 2 reptiles, a total of 26% of all extinctions in the last 500 years. Only rodents caused more extinctions (30%). See Invasive predators major cause of species extinctions.

In one study in Canada, cats (domestic and feral) kill 100 times as many birds as forestry operations and haying and mowing put together.

Here are figures from Canada

Their study is discussed in this article, which I got that table from: Wind farms are hardly the bird slayers they're made out to be. Here's why?

The data is from table 3 of this paper though some of the numbers are slightly changed (maybe the paper has been updated with a correction)

A Synthesis of Human-related Avian Mortality in Canada

I cover this some more in my:

Forestry destroyed about 1,351,340 nests in Canada, Haying destroyed about 2,209,400 eggs or nestlings, and powerline maintenance, about 388,274 nests.

WE CAN DO A LOT ABOUT ALL THIS

We should design skyscrapers, powerlines and cars, to avoid bird deaths, and most of all, we should do something about birds killed by cats. If you put a bell on a cat’s collar and take other precautions such as making sure it is indoors during the evening and morning when it is easiest to kill birds, that can make a big difference to smaller birds. You need to make sure any cat collar is properly fitted with a quick release mechanism so they can get out of it if needs be.

* How to Stop Cats Catching & Killing Birds | Cat Owners Advice - The RSPB (How to Stop Cats Catching & Killing Birds | Cat Owners Advice - The RSPB)

Or you can use a brightly coloured collar, similar in effect:

(click to watch on Youtube)

This is the study they refer to

Cats are by far the biggest human threat to birds. Especially in places like New Zealand of course where there are no natural predators like them. Yet you don't hear that much about it. Even though there are relatively simple things you can do to help especially puting a bell on a cat's collar.

DEATHS FROM BIRD FEEDERS

This is another thing that has increased, people putting out feeders for birds.

These probably help increase the numbers of birds but they can also lead to more mortality as well.

Also, many birds die as a result of bird feeders, placed near a house. You can help with those by making sure bird feeders are placed within 1 meter of a window, and by adding bird collision prevention film over windows, or tape. You can also add decorative patterns to your windows. Here are some snazzy high end designs:

Prevent Birds Hitting Windows | CollidEscape

Here is how you do it if you want to be totally sure birds can’t get through - vertical strips of tabpe that are only four inches apart

I have butterfly stickers on my windows, haven’t done it as thoroughly as this but haven’t had any collisions since I did it. This is what I use:

Butterfly Window Stickers - RSPB Shop

DEATHS FROM FLYING INTO WINDOWS

Again they could die from flying into windows. Perhaps the US has more windows than it did in the 1970s.

The death toll is higher than you would think from the ones you find killed by hitting the window. Many survive the shock, just stunned, only to die later somewhere else where you don’t see it.

As an example, one paper estimates that out of the 5 billion birds who breed in Canada each year. around 24.9 million die of collisions with windows. The vast majority, around 22.4 million of those die from collisions with homes. So, as a home owner, by doing your bit to make your windows easier for a bird to see, you can help to reduce the number of birds that die. It’s less than 0.5% of the total population of all the birds by those estimates, but it may still be significant for some of the species. Also that is in Canada with many wide open spaces - it would be more in a country with a higher density of houses.

Perhaps none of these are the reason but they are simple things you can do to reduce bird mortality, and that helps reduce pressure on the bird populations.

This last section is from

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Facebook group Doomsday Debunked has been set up to help anyone who is scared by these fake doomsdays.

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If you need help

Do message me on Quora or PM me on Facebook if you need help.

There are many others in the group who are available to support scared people via PM and who can also debunk fake Doomsday “news” for you if you get scared of a story and are not sure if it is true. See our debunkers list

If you are suicidal don’t forget there’s always help a phone call away with the List of suicide crisis lines - Wikipedia