Wading Bird Populations and Distributions in the Water Conservation Areas of the Everglades: The 1992 Season

Bancroft, G.; Sawicki, Richard

This report covers the 1992 Systematic Recormaissance Flight (SRF) surveys in the Water Conservation Areas (WCAs) and the Holey Land Wildlife Management Area. This is the sixth season of surveys conducted by National Audubon Society (NAS) personnel and the eighth dry season overall for the WCAs. The SRF program was designed to map the spatial distribution and estimate populations of colonial wading birds (herons, egrets. storks, and ibises) using the system. It is a cooperative program involving Everglades National Park (ENP), the South Florida Water Management District (SFWMD), Florida Game and Fresh Water Fish Commission (FGFWFC). and NAS. Surveys were conducted along 50 east-west transects spaced at 2 km intervals in WCAs 1. 2A. 2B, 3A, 3B, and the Holey Land. The surveys covered 15% of the survey area. They were flown at 80 knots in a Cessna 182 aircraft at an altitude of 200 feet. Two observers counted the numbers and species of wading birds in 150-m-wide strips on the ground on both sides of the plane. The transects were divided into 4 kmz blocks or cells. A longitude was recorded for each bird or flock. allowing them to be assigned to a panicular cell. Surveys were flown from February through June 1992. This was the first year since the 1989-90 drought that the WCAs were rehydrated by the start of the dry season. It was also the first dry season after the restoration of hydroperiods in the Holey Land. Wading birds used the wcAs consistently and in moderately large numbers. The Holey Land contained more birds than were seen during February through June in either of the two previous survey years.