We conducted research at four sites located on sand bars along the Lower Mississippi River between Memphis, Tennessee and Friars Point, Mississippi: Kangaroo Point (Phillips Co., Arkansas, River Mile 647), St. Francis Dikes (Tunica Co., Mississippi, River Mile 672), Porter Lake Dikes (Crittenden Co., Arkansas, River Mile 700), and Cow Island Bend (DeSoto Co., Mississippi, River Mile 715). The sandbars/islands were open expanses of sandy substrate mostly devoid of any vegetative cover and ranged in size from 0.9 km ² to 2.7 km ² during peak nesting.

RESEARCH ACTIVITY

We studied the reproductive ecology of the interior population of Least Terns (Sterna antillarum athalassos) at four colonies during the 1995-1997 breeding seasons. We estimated total number of nests per sandbar, the mean and mode clutch size, mean length of incubation, the number of successful and failed nests, and hatching success.

In order to estimate actual reproductive success, which was defined as the number of fledglings produced per successful nest, we employed a capture-recapture method. A crew of 10 to 15 volunteers would spread across the width of a sandbar and walk its length herding the fledglings (about 12-16 days old) into a funneled drift fence. The drift fence stood approximately 45cm high and extended 600 feet (183m) from the apex of a V shaped setup. Upon capture, each chick was banded, weighed and aged. Fledgling estimates were then made using the Lincoln-Peterson estimate. Over the course of the three years 35 people assisted with the capture-recapture aspect of the study, which we like to call the Chick Roundup.

Chris studied these four colonies of the Interior Least Tern (Sterna antillarum athalassos) found along the Lower Mississippi River. This colonial nester , which may also be found along the Pacific, Atlantic, and Gulf coasts, has been divided into three subspecies. The interior breeding population , in which my interest lies, was first extensively studied by John William Hardy (1957). Because of the recent decline in the population of the interior Least Tern, attributed to the degradation of its riverine sandbar habitat (Smith and Renken 1993, USFWS 1985, USFWS 1990), the species was listed endangered throughout the central portion of the United States on June 27, 1985 (USFWS 1985). Impoundment, channelization, and stabilization projects designed to achieve flood control and navigation objectives have been faulted for population declines. Because of the endangered status of this  species and in lieu of the actions outlined in the species recovery plan, Chris focused on acquiring reproductive estimates that would reflect nest and/or egg destruction and predation events, while excluding non-breeding adults which would inflate adult estimates.