Three Billion Birds
A Shocking Loss
I’m going to share some bad news here. Stick with me, though. I promise there’ll be a spoonful of optimism at the end. Hint: Each of us has untapped power to make a difference.
In 2019, a group of respected ornithologists and conservationists conducted the most comprehensive inventory of North American birds ever attempted. They expected to find that populations of rare species, such as the greater prairie-chicken, were declining, but that common, human-adapted species were increasing and compensating for the overall losses.
Instead, they learned that there are three billion fewer birds flying around now than in 1970. The continent’s overall population of birds has declined by almost 30 percent in those 50 years. And some of the most common species are among the hardest hit – think blackbirds, warblers, finches, larks, and swallows. Even birds that were introduced to this continent, such as house sparrows and starlings, are declining. So not only are we experiencing a loss of biodiversity, but also a significant loss of biomass.
These shocking findings bode poorly for the birds, of course, but also for us. We’re losing not just the enjoyment of having birds as neighbors, but also the ecosystem functions they provide. Birds are critical for nutrient cycling, pollination, seed dispersal, waste disposal, pest control and many other services we depend on – whether we realize it or not. Birds are irreplaceable members of the ecological web that surrounds and supports us.
“It’s as if all birds are canaries, and the entire world is their coal mine.” — Ed Yong, The Atlantic.
Loss and degradation of habitat are the biggest drivers of bird population declines. We’ve paved over, plowed under, chopped up, switched out and generally disrupted the food and shelter birds need. Our landscapes are losing the ability to support them.
That’s the bad news.
The good news is that there are precedents for reversing these kinds of declines. The number of North American raptors (such as hawks and eagles) has doubled since the 1970s, due to a ban on DDT and hunting restrictions. Waterfowl have also increased, thanks to better protection of wetlands. With concerted public-private efforts, it may be possible to stem the tide for the other birds still under threat.
Another bit of good news: there are things you and I can do right now to make our neighborhoods more hospitable to birds.
Desiree Narango, a conservationist at UMass-Amherst, conducted a 2017 study in which she tracked a bunch of Carolina chickadees during breeding season in residential yards around the Washington, DC area. The study confirmed that the native plants in those yards contained a much higher diversity and biomass of caterpillars than did the non-natives. In addition, there was a direct correlation between the number of caterpillar species on a tree and a chickadee’s preference for that tree. (The researchers also noticed that migrating birds who were passing through town at the time also preferred those caterpillar-rich trees.) On the flip side, the chickadees avoided breeding in yards that were dominated by non-native plants, and if they did breed there, they fledged fewer young. The magic ratio appeared to be 70/30: if a yard’s biomass was 70 percent or more native, it was prime real estate for breeding chickadees.
My yard is not yet at the threshold of 70 percent native. I hope we get there soon. (Speaking of which, anyone know of a methadone equivalent for a Japanese maple addiction?) Meanwhile, a key take-away from Narango’s study is that the only thing stopping our urban and suburban yards from being avian habitats is us. Our planting choices determine whether birds will thrive or not. There are concrete steps we can each take to make our surroundings more welcoming to the feathered set. You might call it “birdscaping”:
Plant native plants to provide food. Birds eat the berries and seeds as well as the insects that hang out on native plants. While non-natives may bear fruits, they’re rarely as nutritious as those from natives, and sometimes they’re toxic. Also, non-natives rarely host the kinds and volumes of insects that birds need.
Emphasize native trees and shrubs. In addition to food, they provide shelter, safety and nesting materials. In most of the US, the marquee tree species are native oaks, maples, cherries, elms and hickories.
Provide water. A simple bird bath will do.
Leave the leaves. Leaf litter is like a larder full of insects, spiders and snails for ground feeding birds during the cold months. Also, many moths, butterflies and bumblebees overwinter in leaves, so if you don’t rake them up, they’ll survive to provide more bird food come spring.
Leave snags and logs. If a tree dies, consider leaving its trunk standing, or saving some logs in inconspicuous places. Dead trees make for great nesting holes, and they host tons of insects. Room and board in one place!
Avoid pesticides. Rodenticides used to kill rats get passed up the food chain to owls and hawks. Insecticides used to kill mosquitoes may or may not address the mosquito problem, but they definitely harm the other insects that birds need to feed their young.
Watch your pets. Keep Snowball inside or on a leash. Don’t let Fido chase birds.
We don’t have to wait for the professional politicians and environmentalists to get their acts together. We can be part of the solution by birdscaping right now. Our yards matter. Our choices matter. We have untapped power to make a difference.
Resources:
Kenneth V. Rosenberg, et al, “Decline of the North American Avifauna,” Science, September 19, 2019.
Elizabeth Pennisi, “Billions of North American Birds Have Vanished,” Science, September 20, 2019.
Ed Yong, “The Quiet Disappearance of Birds in North America,” The Atlantic, September 19, 2019.
Desiree Narango, “Cultivating Wildlife Conservation with Native Plants,” Our Expert Video, Grow Native Massachusetts.
Jacob Hill, “Birds and Ecosystem Services,” EnvironmentalScience.org.
“Gardening Is for the Birds: Tips for Creating Bird-Friendly Habitat,” Grow Native Massachusetts.
Accept your love of Japanese maples. Don’t eliminate them unless you stop loving them. Nobody is perfect.
Thank you, Laura. I look forward to your posts. I've planted around 12 native shrubs in my yard over the past 5 years. I think this Spring I'll plant more Summer sweet.