The Diet and Selectivity of the Purple Swamphen in Florida

site mapThe spread of non-native and invasive species is a major problem for U.S. policy maker. A growing number of invasive species coupled with limited management funds to control them make it necessary to develop screening tools to focus management actions on the most harmful species. These screening tools typically require basic biological data and life history information on the invasive species in the invaded ecosystem. This study was designed to fill those basic information gaps for the Purple Swamphen (Porphyrio porphyrio) in south Florida. The goals of my project will be to (1) assess the diet of the swamphen in South Florida and compare it across three different areas and (2) investigate whether the swamphens are selecting or avoiding any types of prey.
swhePurple Swamphens have been part of the south Florida avifauna since 1996 when they first escaped from an aviculturist in Broward County. Since that time, the birds have withstood an eradication attempt and continue to flourish throughout much of south Florida. The potential harm that the birds could hold is uncertain due to the lack of research on these birds throughout their entire range, particularly here in Florida. However, it is presumed that at a high density these birds could have the potential to harm native flora and fauna through diet overlap or competition as well as altering the natural vegetation structure.

coreyThe FWC provided Florida Atlantic University with swamphen carcasses from three different sites; Stormwater Treatment Area 1W (hereafter STA1W), WCA2B, and Lake Okeechobee. We received a total of 91 swamphens from the three different sites in which we took morphological characteristics and dissected all the intact birds. We then sorted and identified the stomach contents utilizing a combination of macroscopic and microscopic techniques. We were interested in determining whether swamphens were selecting for particular plant species in their diets so we also quantified the vegetation community present in WCA2B, using a nested plot design and a Braun-Blanquet scale that measures degree of cover.