Vanishing from the skies

William Searcy, the Maytag Chair in Ornithology, studies animal communication, focusing specifically on the bird songs of New World sparrows. Photo: TJ Lievonen/University of Miami

By Robert C. Jones Jr.

William Searcy, the Maytag Chair in Ornithology, studies animal communication, focusing specifically on the bird songs of New World sparrows. Photo: TJ Lievonen/University of Miami

Vanishing from the skies

By Robert C. Jones Jr.
University of Miami ornithologists explain why the loss of nearly 3 billion birds in 50 years is a serious matter.

Those without an interest in things with wings haven’t noticed, but the bird watchers certainly have: In South Florida, the large migrations of certain avian species have declined dramatically in recent years.

“For a birder, it’s pretty obvious,” said William Searcy, a University of Miami ornithologist who has been studying birds ever since he was an undergraduate at Cal Berkeley in the early ’70s. “There are, for example, fewer warblers coming through in the fall. Historically we’ve had spectacular fall migrations of those species, but it’s been falling off.”

And it’s just not warblers. Populations of many other bird species across North America—from swifts and swallows to sparrows and thrushes—are dwindling at an alarming rate, their distinctive songs becoming ever more rare.

With the journal Science reporting that there are nearly 3 billion fewer birds in the United States and Canada than there were 50 years ago, avian enthusiasts everywhere are sounding the alarm, warning that the dwindling numbers of birds could have a serious impact on our ecosystem.

Birds pollinate flowers and disperse seeds, eat crop-destroying insects, and recycle nutrients back into the earth.

But as their numbers continue to dwindle, the loss will have a “cascading effect on all living organisms” and trigger “major changes in our natural ecosystem, affecting how well our natural world can support life including our own,” said J. Albert C. Uy, an evolutionary biologist and the Aresty Chair in Tropical Ecology at UM, who has studied monarch flycatcher birds on the archipelago of Makira in the Solomon Islands.

The huge decline represents about a 30 percent drop in bird populations since 1970, he said, “and that’s a rapid loss, considering that it happened within 50 years.”

Habitat loss and the wider use of pesticides are considered to be the principal culprits behind their dwindling numbers. But light pollution, buildings, which birds crash into, and even domestic cats that hunt birds are also to blame.

“There’s also been a big decline in insect numbers, and a lot of birds rely on insects for food,” said Searcy, the Maytag Chair in Ornithology, who studies animal communication, focusing specifically on the bird songs of New World sparrows, which are high on the list of avian species that are vanishing.

“This definitely impacts some of the species I work on,” Searcy said of the declining bird populations. “We do still manage to find populations we can work on, but they’ve noticeably declined.”

Grassland species have suffered the worst losses, and sadly, the yearly reproductive cycles of birds have been unable to compensate for the loss.

“Birds can certainly respond to change,” said Uy, “but the changes resulting from human activities are happening too fast.”

Corey Fehlberg, a senior biochemistry and molecular biology major who is president of the UM Amateur Ornithological Society, called the study in Science “disappointing.”

“Not just in that the damage has been caused by human practices, but that likely minimal to no action is expected to be taken to ameliorate the issue,” he said. “Actions to deregulate federally protected lands have surely taken place, though not nearly as much has recently been done to assist the populations.”

Fehlberg and other members of the society, who observe bird life on the Coral Gables campus and on trips to the Everglades and other natural areas, are planning a lecture series to raise awareness about the loss of bird populations.

Instituting other measures could help to reverse the decline, said Searcy. “We’ve addressed other problems that have afflicted birds,” he explained, noting that after the insecticide DDT was banned in 1972, populations of bald eagles and other birds rebounded.

“But it would take a concerted effort to turn things around for this many species declining,” he said.

Still, the effort must be undertaken, said Uy, explaining that everyone can help, even from their own homes by taking steps as simple as placing decals on their windows.

“Windows are a big problem for birds,” he said. “They accidentally fly into windows as they see the reflection of the sky or trees, so installing screens or decals to break the reflection can help.”

Pet owners, he said, could choose to keep their cats indoors, as free-ranging domestic felines kill millions of birds a year, according to a Nature study.

“We could also create better habitats for birds by reducing lawns and growing native plants as well as avoiding pesticides and supporting companies that help birds rather than those that destroy their habitat,” said Uy. “And we should definitely limit our use of plastics, which often end up in landfills and in the bellies of many birds and other animals.”

Said Searcy, “It’s not impossible to turn things around.”