Age-related differences in common Sandpiper Tringa hypoleucos (Linnaeus) foraging and aggressive behaviour in Opa reservoir, Ile-Ife, Nigeria

Abstract

Foraging behaviour of common Sandpiper was studied on the low water level and sand and weed-littered banks of Opa reservoir on the campus of Obafemi Awolowo University, Ile-Ife. Foraging rates differed significantly between the two areas. In each of the two areas the foraging and success rates of adults and juveniles differed significantly while the frequencies of success were similar for both age groups. Experience in searching for and handling of prey may be a primary factor responsible for the observed differences in foraging rates of adults and juveniles. These rates may improve with maturity and experience.

Adults and juveniles in the tail-depressed posture were dominant in aggressive interactions than birds in the tail-level posture. In mixed flocks of foraging sandpipers, four possible types of aggressive interactions occurred. Adult over juvenile interactions occurred more frequently than expected, and juvenile over adult interactions were never observed.

Key Words: Sandpiper, age, foraging, postures, aggression.

Ife Journal of Science Vol.6(2) 2004: 109-113