Assessing the importance of horseshoe crab (Limulus polyphemus) eggs in the diets of migrating red knots (Calidris canutus rufa) and sanderlings (Calidris alba) during refueling stops on selected Flor
   Janell Brush, Florida Fish and Wildlife Conservation Comission

Abstract: Many shorebirds are listed as Species of Greatest Conservation Need in Florida. Successful migration, and subsequent reproduction, in these species depends heavily on food availability at refueling stops. In other areas of the U.S. east coast, horseshoe crab eggs are the major food item at refueling stops for migrating shorebirds, but only anecdotal evidence is available for Florida. Empirical validation is essential for the successful conservation of these species in Florida because habitat loss due to coastal development affects both shorebirds and horseshoe crabs. Some objectives of this project are: (1) Conduct shorebird surveys to determine size and species composition of shorebird flocks on selected beaches. (2) Capture and color-band red knots and sanderlings to determine intra- and inter-annual beach usage. (3) Determine what proportion of the diet of captured red knots and sanderlings is composed of horseshoe crab eggs. (4) Estimate density of horseshoe crab eggs and other shorebird prey items on selected beaches. (5) Assess refueling value of selected Florida beaches to red knots and sanderlings by measuring levels of plasma metabolites in captured birds.Understanding the relationship between migrating shorebird fitness and available prey yields a tractable, quantifiable basis to define habitat quality for migratory shorebirds in Florida, and thus, a better foundation upon which to formulate management recommendations. The findings of this project provide an opportunity to gain insights of migratory shorebird ecology and conservation at larger geographic scales by comparing study results with similar studies conducted in other areas of the U.S. and on other shorebird species.

Award Matching Funds Total
$137,158.00 $137,158.00 $274,316.00

Year Funded Starting Date Ending Date
2006 6/1/2007 6/30/2011

Location: Franklin, Hillsborough, Levy, Manatee, Pinellas and Wakulla Counties