The Trump administration has announced a position on protecting migratory birds that is a drastic pullback from policies in force for the past 100 years.
In 1916, amid the chaos of World War I, U.S. President Woodrow Wilson and King George V of Great Britain signed the Migratory Bird Treaty. The Migratory Bird Treaty Act (MBTA) wrote the treaty into U.S. law two years later. These measures protected more than 1,100 migratory bird species by making it illegal to pursue, hunt, take, capture, kill or sell live or dead birds, feathers, eggs and nests, except as allowed by permit or regulated hunting.
This bold move was prompted by the decimation of bird populations across North America. Some 5 million birds, especially waterbirds like egrets and herons, were dying yearly to provide feathers to adorn hats, and the passenger pigeon had just gone extinct. Fearing that other species would meet the same fate, national leaders took action.
Now the Interior Department has issued a legal opinion that reinterprets the act and excludes “incidental take” – activities that are not intended to harm birds, but do so directly in ways that could have been foreseen, such as filling in wetlands where migrating birds rest and feed. Why? For fear of “unlimited potential for criminal prosecution.” As the argument goes, cat owners whose pets attack migratory birds or drivers who accidentally strike birds with their cars might be charged with crimes.
But the MBTA has not been enforced this way. It is applied to cases of gross negligence where potential harm should have been anticipated and avoided, such as discharging water contaminated with toxic pesticides into a pond used by migratory birds. This new reading of the law means that companies will escape legal responsibility and liability for actions that kill millions of birds every year.
Pollution, development and habitat loss kill birds
Purposeful killing is only one of many threats to migratory birds. Habitat loss, invasive species, pollution and collisions with buildings take heavy tolls on many species. According to the U.S. Fish and Wildlife Service, every year more than 40 million birds are killed by industrial activities or structures such as power lines, oil pits, communication towers and wind turbines. The 2010 Deepwater Horizon oil spill in the Gulf of Mexico killed more than 1 million birds in a single event.
Seventeen former Interior Department officials representing every presidential administration from Nixon through Obama have written a memo expressing deep concern about the new policy. As they explain, the MBTA has given industries a strong and effective incentive to work with government agencies to anticipate, avoid and mitigate foreseeable death or injury to birds.
For example, it prompted energy companies to install nets above pits where they store waste fluids from oil drilling. Because these pits look like water sources, birds often land on them and can become trapped and die. Installing nets over the pits has cut annual bird deaths from roughly two million birds yearly to between 500,000 and one million. Not perfect, but a meaningful improvement.
Global citizens, global consequences
Because migratory birds don’t recognize international boundaries, the consequences of reinterpreting the MBTA may be felt across borders. In one year, an individual warbler may spend 80 days in Canada’s boreal forests, 30 days in the United States at resting and refueling sites during migration, and over 200 days in Central America.
At the Cornell Lab of Ornithology, we have constructed maps and animations using data collected by volunteers for eBird, the world’s fastest-growing biodiversity database. These references illustrate how migratory birds connect countries. Many spend the year in locations that span the Western Hemisphere.