Saturday, May 31, 2008

Shorebirds' Migratory Wetland Habitat Declining Fast

ScienceDaily (Mar. 26, 2008) — A decline by more than 70 percent of several North American shorebird species since the early 1970s has brought state, federal and international concern about conservation efforts for these birds and their wetland habitat. Craig Davis, Oklahoma State University associate professor of wildlife ecology and management, is particularly interested in conservation measures aimed at slowing the decline. “Many shorebirds have become species of concern,” Davis said. “Their population has declined to the point where we would not want them to go any lower.”
Davis, a researcher and teacher in OSU’s department of natural resource ecology and management, explains that species of concern are not endangered but deserve the attention of biologists and wildlife agencies. “Collectively some species have probably declined 50 percent to 60 percent in the last 30 or 40 years. The precipitous decline is primarily due to wetland habitat losses,” Davis said. “Wetlands worldwide have seen great losses.”
Shorebirds stop over in Oklahoma to utilize wetlands and other waterways to rest and feed during both their spring and fall migrations. Davis said little is known about how landscape patterns and land use influence shorebirds migrating through the state.
Davis is directing a study about the distribution and ecological needs of shorebirds during their migration through Oklahoma’s Mixed Grass Prairie Region. Recently, the Oklahoma Department of Wildlife Conservation awarded a grant through the State Wildlife Grant program to the NREM department and Oklahoma Cooperative Fish and Wildlife Research Unit at OSU. The goal of the project is to provide conservation and management recommendations to ODWC and others.
“What is important about these birds, in terms of Oklahoma, is that a lot of these birds are Arctic breeders,” Davis said. “They actually nest in the Arctic – western sandpiper is an example – they nest in the tundra. They spend almost eight months of their annual life cycle migrating. Many migrate all the way to South America.”
From a migration standpoint, some of Oklahoma’s wetland areas are critical for the survival of these birds. “When they arrive up in the Arctic, often there is not food and they may encounter blizzards in a late winter,” he said. “They need to bring resources with them. Birds don’t use fat for insulation. What they use the fat for is energy to power their flight and for putting energy into their egg production.”
Davis likened the shorebirds loss of wetland areas along their migratory flyways is similar to motorists traveling in unpopulated areas without service stations: They have to be certain they have fuel to reach their destination. “When you start losing these wetlands, these birds have to use a lot more energy to get to the next one. They are going to be in poorer condition and it will affect survival,” he said. “The other issue related to wetlands specific to shorebirds is that those wetlands remaining are highly degraded.”
Davis hopes increased information about the various species migrating through the state will aid in improving conservation of many wetland areas on which the shorebirds rely. The NREM study, begun in July 2007, will conduct spring and fall shorebird migration surveys at sites throughout Alfalfa, Blaine, Canadian, Garfield, Grant, Kingfisher, Logan, Major, Oklahoma and Woods counties. Davis said the two-year study is using Geographic Information System data to determine how the landscape and variability of local factors in each area affect shorebird distribution, abundances and species compositions.

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