•  
  •  
 

Abstract

The Great Blue Heron (Ardea herodias) and Roseate Spoonbill (Platalea ajaja) are long-legged wading birds that can forage throughout a 24-hour cycle. Nocturnal foraging enables these species to take advantage of optimal foraging conditions and reduced competition. This study aims to investigate how environmental factors influence the nocturnal foraging behavior of these species. To monitor foraging activity, we deployed 17-18 infrared cameras from dusk until dawn from 4 October 2023 to 24 July 24 2024, covering two sampling periods across different habitats within Fort De Soto County Park, a barrier island complex in Tampa Bay, Florida. We compared the frequency of sightings in open water to mangroves and assessed the influence of sky brightness, tide direction, tide height, and temperature on foraging behavior. Our cameras recorded Great Blue Herons foraging in 26 of 75 observations and Roseate Spoonbills foraging during 20 of 27 observations. Our analysis for periods of nocturnal activity showed that both species were active consistently between dusk and dawn with a prominent peak around midnight. Both species were primarily observed in open water, despite approximately half of the cameras facing mangroves. Great Blue Herons were significantly more likely to forage when the night sky was brighter and the tide was lower. No significant associations were found between the variables and Roseate Spoonbill foraging behavior. Our data confirm that both species forage nocturnally, which increases their ability to forage at the best tides, when human disturbance is lower, and perhaps when there is less competition.

Download

Share

COinS