Response to Study: "Decline of the North American Avifauna"

"There are some who can live without wild things and some who cannot.  Like winds and sunset, wild things were taken for granted until progress began to do away with them."

Aldo Leopold, 1949

Last week, on September 19, 2019, the journal Science published the results of a groundbreaking study, the first of its kind to document, with certainty, that North American birds are in big trouble.

Young male House Finch

Observant folks who have been around a while have been saying it for some time: "There just aren't as many birds around now as there were back in my day."  Indeed, numbers of birds have dropped dramatically over the past 50 years, and now we have the data to prove it.  It's not just a hunch, not just a feeling, not just the tendency to look at the past through lenses tinted with nostalgia for the "good ol' days."  Grandpa is right: there are fewer birds today than there were "in his day."

Birds really are in decline.  This is, in fact, a biodiversity crisis.

529 species of North American breeding birds were included in this study, which represents 76 percent of all breeding birds in North America.  The study went beyond simply looking at extinctions, and instead focused on declines in populations of even the most common and widespread birds, which points to the reduced integrity and function of nearly every ecosystem across North America.

Contributing authors hail from an all-star lineup of organizations, including Cornell Laboratory of Ornithology, American Bird Conservancy, U.S. Geological Survey, Migratory Bird Center, Canadian Wildlife Service, and Smithsonian Conservation Biology Institute, among others.

An excerpt from the study's abstract is below:

American Robin

"Using multiple and independent monitoring networks, we report population losses across much of the North American avifauna over 48 years, including once common species and from most biomes.  Integration of range-wide population trajectories and size estimates indicate a net loss approaching 3 billion birds, or 29% of 1970 abundance...  This loss of bird abundance signals an urgent need to address threats to avert future avifaunal collapse and associated loss of ecosystem integrity, function and services."

The four main findings of the study, according to Cornell's newly launched website which has summarized the study for the general public, are:

1. There are nearly 3 billion fewer breeding birds in North America today than there were 50 years ago, in 1970.

2.  It is not only rare and threatened species that are declining; even the most common and widespread birds have suffered drastic declines.

3. Landscapes are no longer able to support as many birds as they once did.

4. Over this same period, from 1970 to the present, conservation efforts have made great strides toward bringing some birds back from near-extinction.

Nesting Anna's Hummingbird

The paper also mentions a couple of other important points to keep in mind:

-- Loss of bird biodiversity in North America parallels loss of biodiversity in other parts of the world.

-- Since birds are comparably easy to study, this loss of bird biodiversity likely indicates a loss of biodiversity across the board in other taxonomic groups (say, for example, insects and amphibians, which we know are also suffering).





And bear in mind, this study only dealt with losses since 1970.  It says nothing of the losses sustained to habitat and associated wildlife in previous decades and centuries, nothing of the extinction of species like the Passenger Pigeon and (probably) the Ivory-billed Woodpecker, of the wholesale slaughter of egrets for their feathers, the extensive logging, agricultural development, urban expansion, etc. that devoured vast expanses of the continent before 1970.  So keep in mind that if we were able to conduct a study that reached back to the turn of the 20th Century, or even before the Industrial Revolution, think how much greater the losses would be.

One of the brilliant things about the study (I think) is that the focus was not on species we know to be in decline, those already listed as threatened or endangered.  Instead, the study considered common, everyday birds that get little attention in conservation circles simply because they seem to be everywhere.  In fact, these common birds - the barn swallows and meadowlarks and juncos that even non-bird people know - which are found across a number of habitat types, actually showed some of greatest declines.  About 90 percent of the birds lost were members of common and widespread families, like the warblers, sparrows, swallows, blackbirds and finches.  Even the aggressive introduced European Starling, known for bullying other birds and out-competing them for limited nest cavities, has shown a surprisingly drastic decline.

Tree Swallow

Data from nearly 50 years of standardized bird monitoring datasets, like Christmas Bird Counts and North American Breeding Bird surveys, were evaluated.  Additionally, data collected by weather radar technology between 2007 and 2017 was used extensively to get a better handle on the scale and timing of the natural phenomenon known as bird migration.  Many migrating songbirds travel by night, so while we are familiar with large flocks of geese and cranes flying in formation overhead, the nocturnal songbird migration goes largely unobserved.  Weather radar is able to pick up these migrating flocks of birds, providing data that would be virtually impossible to gather otherwise. (Check out Cornell's site, BirdCast, for real-time bird migration forecasts and live migration maps.)

A trio of juvenile Western Kingbirds

Data gathered from this method shows a 14 percent decrease in nocturnal spring-migrating birds in just the last ten years.

Findings indicate that today, there are 1 billion fewer birds across all of North America's forests than there were 50 years ago.

Coastal shore bird numbers are down by one-third.

Juvenile Barn Swallow

Aerial insectivores, birds that make their living by catching flying insects on the wing, like swallows, flycatchers and nighthawks, have lost 160 million birds, or 32 percent of the population.  2 in 5 Barn Swallows have been lost since 1970.

Taken as a whole, migratory birds, which include tropical and subtropical species that not only depend on North American breeding habitat, but also Central and South American overwintering habitat, have declined drastically.  There are 2.5 billion fewer migratory birds filling our skies today than there were only 50 years ago, a 28 percent decline.




Breeding habitats surveyed included wetland, grassland, boreal forest, eastern forest, western forest, arid land, coast, and arctic tundra.  It also includes categories for species that are forest generalists and habitat generalists, migratory birds, and aerial insectivores.

A summary of each habitat type is below:

Sanderlings

Coastal Habitats: saltmarsh, beach, tidal estuary, mangroves, rocky cliffs and islands
(38 species surveyed)
6 million fewer birds today than in 1970 (a loss of 15 percent)
Spotlight bird: Sanderling
Major threats: Coastal development and human beach activity (off-road vehicles, free-range dogs, litter and food scraps which contribute to inflated populations of nest predators like gulls and corvids)




Arctic Tundra: treeless region across the northern parts of North America
(51 species surveyed)
80 million fewer birds today than in 1970 (a loss of 24 percent)
Spotlight bird: Snowy Owl
Major threat: Warming temperatures caused by climate change

Cactus Wren

Aridlands: arid, shrub-dominated communities (sagebrush, chaparral, desert scrub, barren rocky cliffs, thornscrub) in southwestern U.S. and northwestern Mexico
(62 species surveyed)
35 million fewer birds today than in 1970 (a loss of 17 percent)
Spotlight bird: Cactus Wren
Major threats: Habitat loss to urban expansion, and oil and gas development






Boreal Forests: the true boreal forest of Canada and Alaska (as opposed to the boreal zone of spruce-fir forests found at high elevations and lower latitudes)
(34 species surveyed)
500 million fewer birds today than in 1970 (a loss of 33 percent)
Spotlight bird: 9 in 10 Evening Grosbeaks are gone.
Major threats: Logging, oil and gas development, climate change

Not a Pinyon Jay, but another western forest dweller,
the Steller's Jay

Western Forests: temperate forests of western U.S. and Canada, south of the boreal forest; includes coniferous forests, oak forests and woodlands, pinyon-juniper forests, riparian forests and Northwest rainforest.
(67 species surveyed)
140 million fewer birds today than in 1970 (a loss of 30 percent)
Spotlight bird: Pinyon Jay
Major threats: Logging, development, fragmentation, wildfire, drought, climate change





Eastern Forests: temperate forests of eastern U.S. and Canada, south of the boreal forest; includes northern hardwoods, oak-hickory forests, pine-oak forests, southern pine forests and bottomland hardwood forests.
(63 species surveyed)
170 million fewer birds today than in 1970 (a loss of 17 percent)
Spotlight bird: 6 in 10 Wood Thrushes are gone.
Major threats: Logging, development, fragmentation; many of these species are migratory, and threats to their overwintering habitat in Central and South America are wide and varied, and poorly understood.

Dark-eyed Junco

Forest Generalists: species found in similar abundance in two or more of the above forest biomes
(40 species surveyed)
482 million fewer birds today than in 1970 (a loss of 18 percent)
Spotlight bird: Dark-eyed Junco
Major threats: Habitat loss and fragmentation due to logging and development

White-crowned Sparrow

Habitat Generalists: species found in similar abundance in at least three different habitats, usually including forests and non-forest habitats
(38 species surveyed)
417 million fewer birds today than in 1970 (a loss of 23 percent)
Spotlight bird: White-crowned Sparrow
Major threats: The loss of even the most adaptable species points to multiple threats and simply cries out that the situation has become dire.

Western Meadowlark

Grassland habitats, which include native grassland and prairie as well as pasture and agricultural land that supports grassland birds, have taken the biggest hit, with the highest number of birds lost.
720 million breeding individuals from 31 species have been lost since 1970, which is a 53 percent decline.

So, grasslands across the continent have less than half as many individual birds living and reproducing in them as they did just 50 years ago.

Nearly 75 percent of grassland species are in decline.
3 in 4 Eastern Meadowlarks have been lost.
Threats to grassland habitats include rampant urban and agricultural development, alongside excessive pesticide use.

Northern Pintail

Wetland birds alone seem to be faring alright, thanks to herculean efforts to restore freshwater, inland wetlands over the last half-century, and numbers of waterfowl have actually increased (by 35 million individuals, or 56 percent) since the 1970's.

We owe this relative conservation success story largely to the initiative taken by groups and individuals who value wetlands and waterfowl for their recreational potential.  In other words, we have duck hunters to thank.  The great irony (which I still struggle with, to be honest) is that we owe the very existence of wetlands in California (and the rest of the U.S.) to conservation efforts made by those who enjoy shooting birds.  Humbling, perhaps, and certainly hard to swallow for those of us who tend to be self-righteously conservation-minded.

Osprey

The bird family that includes hawks and eagles has also increased, by 78 percent.  Bald Eagles have increased by around 15 million birds over the last 50 years, and Osprey numbers have quadrupled due largely to the ban placed on DDT in 1972.  (DDT is a formerly widely-used synthetic chemical insecticide which persisted in the environment, working its way up the food chain and causing thin egg shells which resulted in reproductive failure for birds like eagles, Ospreys, and Peregrine Falcons.)





Thanks to conservation efforts, woodpeckers have also seen an increase of 14 million individuals over the last 50 years.

These examples show that habitat restoration and conservation-focused legislation really does work to preserve species and bring others back from near-extinction.

Though pinpointing causes of decline was beyond the scope of this particular study, scientists are in agreement that habitat loss is the biggest factor contributing to the decline in birds.  Behind habitat loss is habitat degradation, which happens as habitat is fragmented, polluted, or changed by the spread of non-native and/or invasive plants.

Direct human-caused deaths to birds are caused by outdoor cats (which function more or less like an invasive species and top-class predator in the ecosystem), and collisions with windows (especially glass skyscrapers), vehicles, power lines, wind turbines, etc. etc.

From there it gets more complex: pesticides harm birds directly through poisoning and indirectly as they reduce their food supply (i.e. insects).  Climate change is the wild card: we know it's happening, we know it's caused largely by humans and the burning of fossil fuels, but no one knows just yet  (to my knowledge) exactly what affect this is having on bird numbers.

Snow Geese at sunset in a restored wetland

Why, you might ask, does any of this matter?

The health of bird populations and the biodiversity of bird species act as a sort of barometer for the health of the overall ecosystem.  And healthy ecosystems provide us with innumerable benefits, from clean water and natural resources to recreational and intrinsic value.

Birds themselves provide ecosystem services in the form of pest control (many birds have voracious appetites for insects, invertebrates and other critters we often consider pests, like rodents), pollination and seed dispersal.

Birds contribute to the economy.  According to a 2016 national survey by the U.S. Department of the Interior, U.S. Fish and Wildlife Service, and U.S. Department of Commerce, U.S. Census Bureau, 47 million people spend 9.3 billion dollars each year engaging in bird-related activities, like birding and hunting.

Red-winged Blackbird

Okay, Nature Girl, you say, so it matters. 

What can we do??

There are seven simple ways suggested by 3billionbirds.org, which I will list here, in addition to a few more radical ideas.

1. Plant native plants!!  This one might be my favorite, because I love gardening, and I love having birds around my home.  Lawns provide almost nothing for birds.  Instead, plant a low-maintenance garden of native plants, which offer shelter, nesting sites and food in the form of nectar, berries, seeds and insects for birds.  If you live in California, try using Calscape to find plants native to your zipcode.  For the rest of the U.S., check out Audubon's database of native plants.

2.  Avoid pesticides (and herbicides) around your home and yard, and support organic agriculture.  From 3billionbirds.org: "Pesticides that are toxic to birds can harm them directly through contact, or if they eat contaminated seeds or prey.  Pesticides can also harm birds indirectly by reducing the number of insects that birds need to survive."

3. Keep cats inside or in a "catio," (heehee, I love this idea!) where they are safe from cars and cat fights, and birds are safe from them!  But really, I think the best thing you can do is spay or neuter your cats!!!  Unwanted, feral cats, which lead brutal, short lives (and make me sad), are responsible for two-thirds of the birds killed by cats.

4. Make windows safer.  Estimates put the annual number of bird deaths due to window strikes in North America around 1 billion.  Birds see reflections of trees and clouds in windows and think it's habitat they can fly into.  Check out some ways suggested by the American Bird Conservancy to make your windows visible to birds.

5. Drink shade-grown coffee.  I wouldn't have thought of this one on my own, since I'm not a coffee drinker (but I do drink tea, and I'm sure there are issues with that as well, which I'll have to look into!)  It's easy to forget that many of our beloved songbirds spend half the year in Central and South America; if that distant habitat is lost or degraded, our birds suffer too.  From 3billionbirds.org: "Three-quarters of the world's coffee farms grow their plants in the sun, destroying forests that birds and other wildlife need for food and shelter...  Shade-grown coffee preserves a forest canopy that helps migratory birds survive the winter...  Insist on shade-grown coffee that's good for birds: It's a win-win... delicious, economically beneficial to coffee farmers, and helps more than 42 species of North American migratory songbirds that winter in coffee plantations, including orioles, warblers, and thrushes." 

6. Reduce your plastic use.  This one is huge and makes my blood boil.  Seabirds and other wildlife ingest and become tangled in plastic, leading to their deaths.  I have seen this first hand, more times than I ever wanted to.  All because we were too irresponsible to properly dispose of (recycle) our plastic waste, or too lazy to just wash a reusable spoon or water bottle instead of buying disposable, single-use ones!!  While plastic may be an inevitable part of our life in the 21st century, we can still be wise about using it and avoid single-use plastics, like bags, bottles and utensils.  I've written more (of course I have) about reducing our dependence on single-use plastics here, here, and again here.  No excuses.

7. Get involved in citizen science! Christmas Bird Counts from the past 50 years contributed data to this study; and you can participate in one this year!  Additionally, new online resources, like Cornell's eBird allow birders across the world to post their lists and contribute to science.  Cornell has also put together several citizen science programs that can be done without leaving your backyard and are fun for all ages.  Consider participating in Project Feeder Watch, Nest Watch, Celebrate Urban Birds or The Great Backyard Bird Count.  Because every bird counts!

8. Support legislation that will protect, preserve and restore habitat!  This is critical, and it works.  We need citizens who care to advocate for things like bans on plastic bags and other single-use plastics, to speak up at their local places of business to create a demand for things like native plants and sustainable, organic products.  And we need to educate each other on the issues we're facing.  Additionally, support organizations like Audubon, American Bird Conservancy, Nature Conservancy, and others; consider purchasing Duck Stamps to support the continued conservation of wetlands and waterfowl.

9. Reduce your footprint.  Look more favorably at high-density living and consider downsizing.  This flies in the face of the American ideal - sprawling suburban house, backyard, white picket fence - but hear me out.  Other countries, like Switzerland, where my family is from, have a much better handle on this idea (if only because Switzerland is such a geographically small country!)  We sprawl in America because we think the available land is infinite, but just think what a difference could be made if we condense and contain our urban jungles and leave the rest of the land alone, building up, rather than out.  Parking lots can be built below or above shopping centers.  Shopping centers, for that matter, can be multi-level.  Moderately-sized flats can be stacked on top of each other.  Everyone "wants" a backyard, but how many Americans really, honestly make good use of that space?  If you can choose a home with a smaller footprint, do so.  And for goodness sakes, content yourself with just one house!

10. Reduce your consumption.  It really all comes down to greed.  We want all the things.  And businesses will happily supply them because they want all the money.  And all those factories, distribution centers, stores, landfills, etc. etc. eat up vast amounts of land that would otherwise be habitat.  It's a never-ending, deadly cycle.  Let's break it!

Restored wetland habitat in California's Great Central Valley

Whew.  You made it to the end of a long post on a topic (or suite of topics) I feel strongly about (as you may have noticed).  Though this study proves that birds are indeed in rapid decline, and we are experiencing a biodiversity crisis, hope is not lost.  While the sky-darkening flocks of previous centuries are gone, never to return (the habitat just isn't there), some habitat has been restored, and some of our birds have actually made remarkable comebacks.

It's up to us, to all of us, to decide how we're going to steward the land, with its wealth of wildlife, resources, and soul-stirring beauty, that has been given to us.

We have been entrusted with an incredible gift; will we show our gratitude by helping it to flourish in beauty and abundance, or will we selfishly squander it?



Those interested can access the full paper here.

Or, read the summary article by Audubon.

If reading a scientific paper just isn't your thing, Cornell and its partners have created a wonderfully user-friendly website which summarizes their findings in attractive graphics.  It was a stroke of brilliance on their part to distill a highly technical paper into a format that is attractive, appealing and intelligible for the lay person. I highly recommend that you check it out at 3billionbirds.org.