The recent mystery concerning blackbirds falling from the sky in Arkansas and, later, Louisiana, caught the attention of the nation at large.
The dead red-winged blackbirds, common grackles, brown-headed cowbirds and European starlings are common birds that flock together in winter, and it appears likely that fireworks on New Year's Eve were the main cause of the die-off of as many as 5,000 birds, according to the Arkansas Fish and Game Commission:
It appears unusually loud noises, reported shortly before the birds began to fall, caused the birds to flush from a roost. Additional fireworks in the area may have forced the birds to fly at a lower altitude than normal and hit houses, vehicles, trees and other objects. Blackbirds have poor night vision and typically do not fly at night.
But bird experts say that the wave of attention to this particular die-off doesn't paint an accurate picture of threats to birds in the U.S. One, mass die-offs of this size aren't all that uncommon, from both natural and human causes; two, there are many well-documented longterm threats to U.S. birds; and three, the losses from these threats endanger one in three U.S. bird species, according to the 2009 State of the Birds report by the U.S. Fish and Wildlife Service.
"When you look at the totality of human-caused threats to birds, it has got to give cause for serious concern about our cumulative effects on their populations," said American Bird Conservancy vice-president Mike Parr said.
Here's a look at some major preventable deaths of birds:
As many as 1 billion birds are killed each year from collisions with buildings, according to American Bird Conservancy. Migrating birds following coastlines, where city skyscrapers are also common, are particularly at risk. Lights in skyscrapers can disorient birds, and glass can create a mirror effect that induces collisions as birds either fly toward what appears to be open sky or attack their own reflections, perceiving images of themselves as other birds in their territory. Another 50 million birds may die after colliding with communication towers. Siting, design and lighting schemes can all minimize the threat of collisions.
When pet cats are allowed outside, they often make lunch or sport of birds in the neighborhood, and feral cats are a particular problem, according to American Bird Conservancy, which estimates that as many as 500 million U.S. birds may be killed by cats every year. Keeping pet cats indoors is one solution, and sterilizing (or eliminating, as American Bird Conservancy advocates) feral cat colonies is another.
Whether it's suburban sprawl in the U.S., sugar farms in Brazil or coffee plantations in Central America, the loss of habitat is an ongoing and growing threat to U.S. birds, according to the National Audubon Society. Quantifying the loss of birds due to habitat loss is a big challenge, but the impact is clear on many individual species particularly songbirds that make annual long-distance migrations between continents. "Smartgrowth" planning strategies in the U.S., shade-grown, bird-friendly coffee growing and other conservation farming in South and Central America, and wildlife habitat in your own back yard can all help reverse this trend.
Global trade and travel have introduced many species to new continents or regions, where they sometimes run rampant, to the detriment of native populations. Case-in-point: The birds of Hawaii, which are particularly vulnerable because unique species evolved separately in isolation on individual islands that are now under siege from foreign species introduced by residents and tourists. Already 71 of the Hawaiian islands' 113 native bird species have gone extinct. Ten other species haven't been seen for 40 years, and could well be extinct today. (The Daily Green named birdwatching in Hawaii as an endangered vacation because of this.) The only strategy that has proved at all effective against invasive species is preventing the introduction of new species (eradicating them from new habitats is expensive and rarely successful) so always heed travel advisories regarding plants and animals.
Fishermen are supposed to catch fish, but sometimes they catch birds, too (and sea turtles, dolphins and other fish they don't intend to sell collectively called "bycatch"). World Wildlife Fund estimates that 26 species of seabirds, including 23 albatross species, are threatened with extinction because of longline fishing. Other fishing impacts include the infamous loss of red knots because the food they feast on midway between the winter and summer habitats horseshoe crab eggs in Delaware Bay is in sharp decline because fisherman catch horseshoe crabs as bait for other fish. You can avoid fisheries with bycatch problems and buy sustainable seafood by using these three Websites.
The use of pesticides, particularly on farms, but also on lawns and gardens, claims as many as 15 million birds ever year, according to American Bird Conservancy. Environmental groups have worked for years to ban harmful pesticides, and recent years have seen the banning of several of the chemicals most harmful to birds. At home, consider integrated pest management to minimize or eliminate the use of pesticides, and buy organic food and fibers whenever possible because they will have been grown without the use of pesticides.
Before it was widely recognized as a problem, many birds were killed by wind turbines erected in areas also frequented by migrating birds or other colonies (this is also a problem for bats). Increasingly, wind farms are being erected only after consideration of their impact on wildlife, and the types of turbines used are designed to be less risky than those used years ago. It should be noted that other forms of energy development can be just as damaging: Coal mining strips away forest habitat and offshore oil can create deadly slicks, for instance.
The granddaddy of all threats to wildlife, experts generally agree, is climate change. The list of possible impacts is great, ranging from the relatively obvious (the loss of high-altitude alpine habitat on mountains as temperatures warm) to the subtle (the un-syncing of natural phenomenon, such as the migration of birds timed to the emergence of insects that they eat each spring). The 2010 State of the Birds report, now a government effort, focused on the widespread effects of climate change on U.S. birds. While stopping global warming will almost certainly require national and international action, there are many things individuals can do, starting with reducing energy use at home.
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