Written by Bryan Watts
October 14, 2008
The Center for Conservation Biology and the Virginia Coast Reserve of The Nature Conservancy have recently compiled results from 2008 aerial surveys for whimbrels and other shorebirds along the seaside of the Delmarva Peninsula in Virginia. Whimbrel begin to move into the area in early April, reach a peak population in early May, and move north by the last week of May. Comparison of the peak whimbrel count for 2008 to surveys conducted by the same survey team during the springs of 1994-1996 show a decline of approximately 50%.
The seaside lagoon complex of the lower Delmarva Peninsula has been designated as a hemispheric shorebird reserve, recognizing its importance to migrant shorebirds. The site represents a critical, coastal staging area for whimbrel, where birds congregate to feed on the staggering numbers of fiddler crabs that inhabit the lagoon system and build up energy reserves before making their last overland flight to the breeding grounds. The importance of the lower Delmarva as a refueling site was demonstrated this past spring when a bird fitted with a satellite transmitter left the shore and flew more than 5,000 kilometers (3,200 miles) to the MacKenzie River (describe where) in 146 hours.
The whimbrel is a highly migratory shorebird wintering in Central and South America and breeding in Alaska, around the Hudson Bay and in the Northwest Territories of Canada. Due to the remote location of breeding sites and their dispersed distribution, surveys on the wintering grounds and within significant migratory staging areas such as the lower Delmarva Peninsula represent the best indication of status and trends. It remains unknown, to what extent to which the decline in peak counts on the lower Delmarva portends broader population trends. Threats faced within breeding and wintering grounds, as well as within coastal migration staging areas, are poorly understood. Continued research is planned by the Center for Conservation of Biology and the Nature Conservancy to study the ecological requirements of migrant whimbrels staging along the peninsula and to link populations across their migratory staging, breeding, and wintering areas.