For the Birds Radio Program: Missing Pelicans
The largest American White Pelican colony in the world, in North Dakota, has suddenly been abandoned and no one knows why, or where the birds went.
This year has been a strange and discomfiting one for Americans, and apparently also for birds. Our cold, wet May and June have been disastrous for small insectivorous birds, leading to lots of missing birds on many breeding bird survey routes. But the most dramatic and perplexing bird disappearance was at the Chase Lake National Wildlife Refuge in North Dakota, the place with the largest nesting White Pelican population in the world. About 30,000 pelicans have been nesting on three islands for many decades. But beginning on May 24, suddenly the pelicans started disappearing from two of the islands, and over four days, 27,000 of the pelicans disappeared, leaving their eggs and chicks behind. A mere 80 adults remained on those two islands. Then on June 17, scientists reported that 2,000 pelicans had disappeared from the third island, again abandoning their chicks and eggs, and leaving only 400 adults there.
One might think that 29,000 pelicans couldn’t just disappear, but even though this has been widely publicized and though May and June are months when a great many bird surveys are done throughout the continent, most of the birds don’t seem to be showing up anywhere.
Last year this population suffered heavy losses from West Nile Virus, which killed fully half of the chicks. Some scientists speculated that the carcasses from last year provided an unexpected feast for coyotes, and thought that two dens of coyotes near the colony this spring might have been harassing the pelicans with hopes of a repeat feast. In case these coyotes spooked the first birds, causing their disappearance, biologists trapped them in late May, but the second group of pelicans disappeared after this, so the coyotes were apparently not the problem. Pelicans seldom abandon their babies even under duress, and for so many to up and leave at the height of the nesting season is utterly unprecedented, and frightening. Somewhat larger than normal numbers of pelicans have been turning up in Yellowstone National Park and at some Minnesota and Canadian sites, but nowhere near 29,000 have been accounted for. Ken Torkelson, a spokesman for the U.S. Fish and Wildlife Service in Bismarck, told the Associated Press, “It’s like they packed up and left in the middle of the night - except they didn’t pack up, they just left.”
One curious and disturbing note is that researchers found one pelican carcass which tested positive for botulism, and a live bird about 15 miles from the colony was showing signs of botulism on June 9. Botulism seems to be cropping up in more and more places this year. I’m concerned that the reduction of services in many cities and states is slowing, or even stopping, the quick and sanitary disposal of road-killed animals. Rotting carcasses can become hotbeds for disease organisms, which can be spread when crows, ravens, vultures, and mammalian or insect scavengers feed on them. The digestive tract of Turkey Vultures kills botulism and other diseases, but the organisms can cling to their feet, to be spread when they visit other carcasses. And crows, ravens, eagles, rats, and many other scavengers can pass botulism through their droppings and their own carcasses if they became poisoned—probably the worst vector is the fly. The popular anti-tax movement is demanding ever greater reductions in government services, but leaving roadkill to rot is fundamentally uncivilized, bringing our modern society back to the Middle Ages in terms of basic public health and sanitation—only back in the Middle Ages, automobiles didn’t kill billions of animals every year, leaving them to decay in the open. Obviously there have always been dead carcasses for scavengers to eat, but the vast majority of animals in wild areas die through predation and are disposed of fairly quickly.
Whatever caused the pelican disappearances, people are hoping against hope that the birds are alive somewhere. The only question is, where?