Characteristics Affecting Prey Vulnerability and Avian Habitat Selection in the Florida Everglades

The vulnerability of prey to capture plays a fundamental role in determining
overall prey availability for wading birds. Structural complexity can act to decrease prey
vulnerability and influence foraging habitat selection. To determine how structural
complexity can affect habitat selection I conducted a use vs. availability study throughout
the Florida Everglades in 2005 and 2006. Results indicated that wading birds chose
foraging sites that had less emergent vegetation and a thicker flocculent layer relative to
random sites. Submerged vegetation, and the height of emergent vegetation did not
affect wading bird site selection. A difference in habitat selection between years was
evident due to hydrological conditions. Ideal hydrological conditions are probably the
most important parameter to wading bird success. Other factors affecting prey
vulnerability became increasingly important in years of poor hydrology, probably
because the penalty for choosing low quality foraging habitat would be greater than in
years of more optimal conditions.