NCJ Number
140728
Journal
Aggressive Behavior Volume: 18 Issue: 3 Dated: (1992) Pages: 241-248
Date Published
1992
Length
8 pages
Annotation
This experiment involving a live predator tested the null hypothesis that there are no differences in aggressive defense as a function of predator type, habitat, or duration of stimulus. This research was carried out using herring gulls as the predators and antipredator black skimmers, living in both sandy beach and salt marsh environments.
Abstract
Skimmers living in salt marshes were more aggressive toward the herring gull than were those nesting in beach habitats, even though there were no measurable differences in vegetation cover, distance from the edge of the colony, or nesting density between the two areas. Aggression increased during the first 3 minutes of the test and was highest when the gull moved compared to when it was stationary. The antipredator skimmers made few movements when a person was with the gull, but became drastically more aggressive when the gull remained alone. The findings showed that skimmers may be more aggressive toward predators that threaten their chicks and eggs than previously believed. 1 table, 1 figure, and 46 references