Feeding Ecology of Breeding Gadwalls on Saline Wetlands

Publisher Website
Google Scholar
Abstract
The feeding ecology of breeding gadwalls (Anas strepera) from saline wetlands in North Dakota [USA] was examined in relation to sex, pair mates, reproductive status, food availability and wetland type during the spring and summer of 1971 and 1972. Esophagi of males and females contained 40.4 and 48.2% animal food, respectively, between 17 April and 25 Aug. Animal foods consumed by paired females varied with reproductive condition and were independent of their mates. Invertebrates increased from 47.7 .+-. 17.4% in the diet during prelaying to 72.0 .+-. 18.4% during laying and declined to 46.3 .+-. 30.0% during postlaying. Aquatic insects dominated the diet during egg laying and were selected disproportionately relative to their availability. Esophageal contents indicated that diversity of plant and animal foods in the diet varied inversely with specific conductance. Major factors influencing food selection of the breeding birds are discussed as interactions among their physiological status, their anatomical and behavioral characteristics, and the abundance and behavior of food organisms as influenced by chemical and physical features of the environment. These interrelated ecological factors apparently act simultaneously to control the phenology of events and determine the foods utilized.

This publication has 3 references indexed in Scilit: