Snail Kites’ Affinity for Home Leaves It in More Peril

Snail kites are important for at least two reasons: Bird enthusiasts flock to see them in their natural habitat, so they're a bit of a tourist magnet. Secondly, wildlife managers use the snail kite as a barometer for conservation actions to preserve the Everglades, said Robert Fletcher, a UF/IFAS associate professor of wildlife ecology and conservation.

The population of snail kites declined from about 3,500 to about 700 from 1999 through 2008. The bird has bounced back a bit, to about 1,700 birds in 2014, mostly in the lake habitats to the north of the Everglades.

Because of the snail kite's dwindling population, Fletcher led a 17-year study into dispersal patterns of the federally endangered bird. The study, published in the journal Proceedings of the Royal Society B, spans the years 1997 to 2013.

Researchers counted birds and determined where individual snail kites nested over time to see if they returned to their abodes. The scientists' work shows that despite the fact that snail kites move around considerably, they have strong preferences for places like home, and this impacts breeding, Fletcher said.

Other species often prey on the snail kite's nests; thus, leaving the bird unable to reproduce as effectively, he said. Snail kites that leave their nesting areas in the Everglades usually find new homes that resemble their old ones, Fletcher said. Yet snail kites that disperse to places like their home are more likely to have their nests preyed on.

"This is important and surprising and is some of the first evidence of this migratory pattern in vertebrates," he said.

Scientists have long been interested in studying how your birthplace influences people and animals later in life. Fletcher describes the snail kite's affinity for its birthplace as something akin to a line from "The Wizard of Oz." As Dorothy says near the end of the movie, "There's no place like home."

"For people, we have strong evidence of this," Fletcher said. "For example, I was born near the Smokey Mountains, and when I left home, I longed for a move to other areas where there were mountains. For animals, it has been suggested to occur, but there has been limited evidence in wild populations. Our work provides strong evidence for these effects and shows why they are important."