The U.S. and Canada have lost about a quarter of their birds since 1970, according to a study reported in the journal Science. This is a loss of about 3 billion wild breeding birds that live in most habitats.
The drastic loss is connected with global losses of insects, amphibians and other wildlife.
Seven institutions were involved in the study that looked at 529 breeding bird species in the U.S. and Canada.
Losses of regional birds hit us hardest. Few people may have noticed that we have been seeing fewer indigo bunting, scarlet tanager, ovenbird or rufus-sided towhee. They live in heavy cover and never have been very numerous. But when we look at typical backyard birds like dark-eyed junco, whose population slipped back 175 million individuals, or the white-throated sparrow, which declined by 93 million individual birds, this hits home.
About 90 percent of nearly 3 billion birds lost belong to just 12 bird families.
Findings included 48 years of data from several independent sources including the Christmas Bird Count and the North American Breeding Bird Survey.
Some habitats are apparently more vulnerable than others. A billion birds have disappeared from forests since 1970. Grassland birds have declined by 720 million. Birds that hunt insects on the wing dropped 169 million. Even as a breeding pair of plover returned to breed at Presque Isle this spring, coastal shorebirds have lost a third of their population.
Radar in night skies reveals a 14 percent decline in northbound migrants in just the past decade.
This study did not look into the causes of bird declines. Scientists have identified the loss of habitat as the greatest threat to birds. There are degrees of habitat loss. In many cases, the habitat degrades so it can support fewer birds. In the cases of human development, habitat just disappears from existence.
How many of us have developed parts of our lawns because it makes it prettier to us, even though it devalues bird habitat?
Invasive plants that displace native plants can eliminate food sources. Often the invader that replaces a native plant is not suitable for American birds.
Climate change drives down bird populations. Shifts in the timing of food supplies can be critical to migrating birds.
And how big is this? As you drive across the Midwest and over the flat, southern deserts, you will see huge wind farms stretching farther than the eyes can see. Builders want to put wind farms on major bird migration routes, such as here along the Great Lakes. Increasing thousands of giant windmills with blades spinning hundreds of miles per hour destroy a great number of birds, as well as bats.
It was estimated that in 2012, wind turbines destroyed 573,000 birds. The number of wind turbines has increased considerably since that time. Have we forgotten about the fuss over wind turbines killing bald eagles, one of our national symbols?
Audubon has 58,000 of the large wind turbines in its database. Since 2005, the number has been increasing by about 3,000 wind turbines per year. Audubon estimates that wind turbines kill 140,000 to 328,000 birds each year in North America.
USA Today estimated that 6.8 million birds are killed by collisions with cell towers and radio towers. Still more collide with power lines.
And here is a set of numbers neither bird lovers nor cat lovers should tolerate. Cats account for 1.4 billion to 3.7 billion wild bird deaths.
So is there any mystery why North American bird numbers are declining rapidly?
There are things we can do to help remedy this sorry situation. First, contact and join bird enthusiast groups including American Bird Conservancy, Audubon Society and Cornell Laboratory of Ornithology. These groups and many universities can guide the development of bird-friendly lawns and larger properties.
Fossil fuel is not the villain it is often made out to be. We have developed ways to make emissions less toxic. Doubtless more improvements might be made. My wife’s car has near-zero-emissions. This might not save the world, but it is a big step in the right direction.