For the Birds Radio Program: Where have all the birds gone?
Many people in the northland have noticed the decline in songbirds this year. What is causing it? Laura rounds up the usual suspects. (I think this transcript is the right one for this placeholder.)
Last week, one of the Duluth TV news programs did a short feature about the decline of songbirds throughout the Northland. Everyone wants to know why birds are disappearing, but no one seems to want to hear a complicated answer. Unfortunately, this is no single cause for the decline. Loss of habitat and forest fragmentation here and in the tropics are certainly major causes, but there are an incredible number of other factors exacerbating the situation.
Tall buildings and TV towers kill hundreds of thousands or even millions of nocturnal migrants throughout the United States every spring and fall. Birds are attracted to the lights the way moths are, especially in drizzly or foggy weather, and are killed by colliding with the structure itself or with one another as they mill about in confusion. A single TV antenna tower in Eau Claire, Wisconsin, killed 20,000 birds in a single September night, and 35,000 more on a foggy weekend. Most of these dead birds were warblers and thrushes. Nationwide, there are very few towers that are monitored by ornithologists. Birds that weigh less than a third of an ounce disappear fast in the natural world. Gulls, crows, house cats, foxes, raccoons, and even squirrels take away many carcasses even before dawn, and such tiny birds also drop well inside the weeds under towers, so people in the vicinity of towers have to pay close attention to notice even a huge kill. Most antenna farms, like the Duluth one, are posted against trespassing, which makes it even more difficult to learn exactly how many birds are dying at them each year.
Pesticides have taken an unbelievable toll on birdlife. Although most people associate pesticides with agriculture, at least as bad are the ones people use on their lawns, to kill weeds and cutworms and other insect pests. Every one of the national lawn care companies uses pesticides, both insecticides and herbicides, which are lethal to birds. And although all of these chemicals are EPA registered, virtually none of the most commonly used ones has ever been tested for its effects on native songbirds. Notwithstanding their immediate poisonous effect, the insecticides have another, even more insidious effect. They kill not only pest insects but also earthworms, ladybugs, and other useful creatures, eliminating the natural food sources for most backyard birds. So even those literate birds that can read the lawn care warning signs will lose their food sources after a lawn has been treated. In the 11 years I’ve lived in Duluth, the robin population has apparently dropped by 2/3.
House cats take an enormous toll of birds—far more than native predators, who are spaced much further apart and aren’t subsidized by pet food. Studies in England and at the University of Wisconsin are finding that the primary cause of the declines of some bird species is cat predation.
This year’s cold July may have killed a few birds outright, but its worst effect was to make it impossible for most birds to find enough of the right kinds of insects to feed their babies while staying on the nest to keep them warm.
All in all, like the Walt Disney cartoon says, it’s tough to be a bird. Of course, some species will be with us forever—gulls, crows, pigeons, starlings, and other street smart creatures will never be endangered as long as people continue to make street life so easy. The most fragile are the songbirds that fill our lives with beauty and song. If we don’t do something quick to save them, our human world will be darkened as, one by one, those bright little avian lights are snuffed out forever.