Nests of the Black-crowned Night Heron and the Snowy Egret were examined in five central Utah colonies in 1973 to determine the spatial distribution within the colony. Nest locations of the 1085 nests of the two species were plotted to the nearest foot with an alidade and plane table. Tests of randomness, clump size, association, segregation, and T distribution were utilized. No differences between species were noted for the distance to the nearest and the next nearest nest. The Night Heron nested closer to other Night Herons and more often than did the Snowy Egret which non-significantly selected either species to nest closest. The Snowy Egret nests were 1.7 times higher than the Night Heron nests. Both species nests were aggregated within the colony. The association between the species within the habitat was positive but were segregated within the colony. Nest succession within a colony indicates that the Snowy Egret becomes more selective as time progresses but that the Night Heron remains selective throughout the entire season.
College and Department
Plant and Wildlife Sciences
BYU ScholarsArchive Citation
Isham, Randall S., "The spatial distribution of the nests of the black-crowned night heron (Nycticorax nycticorax) and the snowy egret (Leucophoyx thula) in central Utah" (1974). Theses and Dissertations. 7786.
Herons, Utah; Birds, Eggs, Utah; Zoology, Utah