Summary

Description

The Mississippi Alluvial Valley MA V is the historic alluvial floodplain of the Lower Mississippi River. Most of the MAV is located in Arkansas, Louisiana, and Mississippi with smaller segments in Tennessee, Missouri, Illinois, and Kentucky Fig. I. Before European settlement, the MA V was a 10 millionha forested wetland system created and maintained by backwater and headwater flooding as well as localized ponding on poorly drained soils. Long duration flooding in the MA V led to sediment and nutrient deposition. Over the last century, most of the land in the MAV has been cleared and converted to agriculture and aquaculture with only 28 of the original area now forested King and Keeland 1999. In addition to changes in land cover types, the MA V has also experienced major changes in hydrology. The building of dams, levees and other water control structures has altered many hydrological processes Elliott and McKnight 2000. Although historical use of the predominately forested region by migrating shorebirds was low, they most likely made use of the sandbars and shores on the Mississippi River as well as the sloughs and backwater areas in the MA V Twedt et al. 1998. Many of these areas no longer exist due to changes in the region. Because shorebirds are concentrated during migration, they are dependent on relatively small areas and especially vulnerable to habitat changes Myers 1983. Open agricultural fields and aquacultural facilities in the MA V now provide much of the habitat for migrating shorebirds Twedt et al. 1998. The Lower Mississippi Alluvial Valley Joint Venture LMVJV was organized in the late 1980s in order to implement the North American Waterfowl Management Plan in the MAV. Partners in the LMVJV include members from state agencies in the joint venture area, several federal agencies, and nongovernment conservation groups. In 1989, the Neotropical Migratory Bird Program, better known as Partners in Flight PIF, was established as a cooperative initiative for the conservation of neotropical migrants and their habitats. An informal coalition between the PIF and LMV JV has developed over the past several years Loesch et al. 1995. Based on consultation with the Western Hemisphere Shorebird Reserve Network, the PIF and LMV JV identified foraging habitat during fall migration as the primary habitat need for shorebirds in the MAV. The U.S. Shorebird Conservation Plan outlined 3 steps for stabilizing and enhancing continental populations of shorebirds. Those steps include compiling existing information, identifying important questions, and prioritizing future research and conservation needs. These plans have been finetuned at the Bird Conservation Region BeR level by the Shorebird Working Group of the LMVJV Migratory Bird Science Team. In the MAV BCR, the top 2 research priorities are estimating the abundance of shorebirds using the MA V during fall migration and estimating fall migration turnover rates. Turnover rates for shorebirds in the MA V are defined as the average time, in days, that a shorebird takes to pass through the MAV BCR. In 1995, the Mississippi Alluvial Valley Bird Initiative developed management objectives for the MA V based on the assumption that the average turnover for a migrating shorebird was 10 days. The primary objective of this study is to estimate the turnover rates of fall migrating shorebirds in the MA V using 2 target species, the pectoral sandpiper Calidris metanotos, PESA and the least sandpiper Calidris minulilla, LESA. We will estimate turnover rates from PESAs using radio telemetry data from 2001 and 2002 and from LESAs using captureresight data from 2002.