WORTH MORE THAN A FLEETING GLIMPSE
By Eileen Dowd Stukel
Top to Bottom: American Avocet, Wilson's Phalarope, Spotted Sandpiper, Semipalmated Plover. Artwork by Carol Decker.
Maybe you've seen them along an ocean's coastline - an undulating wave of birds following the edge of the water as it moves with the tide or the wind - groups of birds that seem to move as one being, busily dipping into shallow water or probing damp soil. Or maybe you've spotted them on a shallow South Dakota wetland in late summer- long-legged, seemingly plain birds that some people call "peeps." They are shorebirds, an amazingly diverse group of birds closely tied to aquatic habitats and the resources that wetland soils and basins provide.
Some of our most familiar birds are shorebirds. The Killdeer, a member of the plover family, is one of South Dakota's most adaptable birds, inhabiting barren sites, such as gravel roads and beaches. A Killdeer cousin, the Piping Plover, is rare both in South Dakota and throughout its range, because of loss of alkaline wetlands and conversion of the Missouri River's riverine habitats to reservoirs. The Upland Sandpiper, formerly called the Upland Plover, is a familiar sight and sound in western South Dakota grasslands. In addition to these familiar summer residents, many more shorebird appearances are fleeting during spring or late summer migration stops. Shorebirds as a whole are an extremely diverse group, not only in appearance, but also in foraging styles, prey preferences, and habitat needs.
Shorebirds perform some of the most amazing migrations of any wild animal in the world. The Bar-tailed Godwit nests in the Alaskan tundra. An estimated 100,000 individuals take a nonstop fall migration journey to wintering grounds in Australia and New Zealand, travelling nearly 7,000 miles. This may be the longest migration of any bird species, and not surprisingly, Bar-tailed Godwits are believed to carry the greatest fat load of any migratory bird studied. The American Golden-plover and Pacific Golden-plover also make incredible nonstop migration flights, often over open
Not all shorebirds migrate thousands of miles at a time, but migrations of any distance require fuel. For shorebirds, that fuel is most often invertebrate animals that are captured, extracted, or gleaned from water, mud, sand, or plants, usually in and around shallow, sparsely-vegetated wetlands. In the Northern Great Plains, wetlands are naturally dynamic, with "normal" conditions often overridden by extremes of drought or flooding. Shorebirds evolved within this changing environment, but wetland losses have taken their toll.
Life history attributes can add to the challenge of shorebird management. Shorebirds are typically ground nesters that produce small clutches. Many species nest in the northern tundra, a climate allowing only short breeding seasons. The short breeding season makes shorebirds vulnerable to impacts from nest predators and disturbance during nesting and brood rearing.
South Dakota hosts at least a dozen shorebird species during the summer nesting season. They are:
Shorebirds are a management challenge, since shorebird species exhibit a tremendous variety of bird sizes, feeding strategies, and migration patterns. As with any management approach, the initial steps are to predict which species or species groups are most likely to be present in an area and determine when they may appear and what they need in the way of prey and feeding conditions (water depth and wetland size, for example). Gauge the site's limitations (can water level be manipulated?), and decide whether shorebird management is compatible with other management priorities (waterfowl production, for example).
In many cases, South Dakota's contribution to shorebird management is most important during the spring and fall migration seasons. Considering the range of shorebirds that migrate through South Dakota, an ideal migration stopover should have a diversity of open, shallow waters, abundant invertebrate populations both in the water and in damp soils, and provide a feeding environment safe from threats, such as excessive disturbance and environmental contaminants. And in keeping with the dynamic theme, these wetland complexes should undergo natural (or artificial) changes, such as drawdowns and reflooding.
Although shorebird management is a complex topic that is a relatively new concept for land and wetland managers, the overall theme of habitat diversity for wildlife holds true. To provide for the array of shorebirds that nest in and migrate through South Dakota, a land manager or landowner should try to provide a variety of diverse and dynamic habitats and monitor the various strategies for their effectiveness for shorebirds.
This article was excerpted from a new SDGFP publication, "Shorebirds of South Dakota." Illustrated by wildlife artist Carol Decker, the booklet has information about shorebirds that rely on South Dakota habitats during the nesting and migratory seasons. Included are nesting species descriptions, general management practices, an identification key, a South Dakota shorebird checklist, and many color illustrations. Watch for this free publication during the spring of 2004.