“Catastrophic” Bird Declines
This is a time of year when it can be hard to imagine that birds are declining. With flocks of sometimes thousands of Tree Swallows swarming the dunes of Sandy Neck in Barnstable or High Head in Truro, marauding bands of over a thousand grackles storming through wooded neighborhoods, and massive flocks of sea ducks forming off Monomoy like smoke on the water, it can seem like all is fine. But a viral new study estimates that, in fact, we have lost nearly a third of the individual birds on the continent since 1970. So how can we reconcile what we see with what we read?
First, a bit about the paper. The authors are well known and respected ornithologists representing several of the heavy hitting organizations in bird research and conservation, like Cornell and the American Bird Conservancy, and the study was published in the prestigious journal Science. They used data from the Breeding Bird Survey and other long-term projects with standardized methods, as well as radar data showing flock size and density of migrating birds over time. As you would expect, some species have declined and others, like ducks and hawks, have increased. When they averaged across all species, which is a little dangerous, they estimated that there are 29% fewer birds than in 1970, which, under their various assumptions, comes out to be 3 billion birds.
Yikes. What I found comforting was that two of the top ten decliners, accounting for 15% of the overall loss of individuals, were House Sparrows and European Starlings, both destructive introduced species that we have been hoping would decline. Two others, Common Grackles and Red-winged Blackbirds, are still superabundant and ubiquitous. This is despite the fact that, in the case of Red-winged Blackbirds, the government exterminates them by the tens of thousands to protect sunflower farms in the Midwest. Another of the top ten is the White-throated Sparrow, which breeds in shrubby forest clearings and edge – luckily, we can create habitat for this species with better forest management, which includes logging. Some of the declining species likely enjoyed population spikes during the agricultural period, and are declining as former farmland returns to forest.
Nevertheless, it seems that about 10% of birds are in serious decline, especially grassland birds and shorebirds, and birds overall clearly need our help. Luckily, some of the primary causes of decline are solvable if we have the will. Keeping cats indoors, eliminating neonicotinoid pesticides, and installing more bird friendly windows in homes and commercial buildings would save billions of birds every year. We can create better habitat by planting native species in our yards and parks, by restoring old farmland to native prairie, and by structuring development to better reduce sprawl.
None of this addresses the “Big C”. Climate change will continue to threaten bird populations, often in ways we don’t yet understand. Birds that nest in the Arctic, where most of the warming is happening, are especially vulnerable to the destabilizing effects of climate change during their super short breeding seasons. And our local coastal nesters like Piping Plovers and Saltmarsh Sparrows will continue to be squeezed by rising sea levels. All we need to reverse all of this is sweeping political change and a near complete restructuring of our global energy economy.
Bur don’t despair – we banned DDT to save Bald Eagles and Peregrine Falcons, and we protected 6 million acres of wetlands under the federal duck stamp program to bring back duck populations. We’ve come together to save birds before, and we can do it again. So consider this report a wakeup call, and let’s get to work.