Habitat selectivity and site fidelity of the GPS-tracked Great Egret Ardea alba during the breeding season

Habitat selection is especially important for avian groups anatomically specialized in foraging in particular habitats, e.g., wading birds foraging in wetlands. Here, for the first time, we investigated the breeding duration, foraging flights, home range, site fidelity, habitat use, and selectivity of seven GPS-tracked Great Egret Ardea alba individuals breeding in Eastern Europe in 2016–2023. The studied individuals arrived at their breeding grounds between 8 March and 24 May and departed between 27 April and 30 September. The duration of staying at the breeding grounds was significantly longer in individuals with breeding site fidelity (mean ± SD: 112 ± 27 days) compared to those less faithful to the breeding site (107 ± 43 d). Successful breeders stayed significantly longer at the breeding site (119 ± 22 d) compared to failed breeders (96 ± 43 d). Distances covered during foraging trips between every GPS location and the colony (11.4 ± 10.7 km) differed significantly between individuals. Individuals performed longer flights during the chick-rearing (11.5 ± 10.7 km), compared to the incubation stage (11.1 ± 10.9 km). Home range areas were significantly larger in failed breeders (min–max: 651.6–320,213 km 2 ; 57,543 ± 106,568 km 2 ) compared to successful breeders (51.9–5,179 km 2 ; 1,362.9 ± 1,599 km 2 ). We showed that none of the investigated variables significantly influenced site fidelity which suggests other factors are at play. Great Egrets avoided urban areas. They mostly explored wetlands, other aquatic habitats, and farmlands. The avoidance of urbanized habitats was pronounced in successful breeders.