Seasonal Variation in Egg Size in Golden Plover Pluvialis Apricaria and Dotterel Charadrius Morinellus Populations

Abstract

In two Golden Plover populations in S. Norway (Jaeren: heather moor at 300-400 m elevation, and Hardangervidda: middle alpine zone at 1200-1300 m elevation) there was a negative correlation between egg volume and the date on which clutches were started. A Dotterel population in the study area on Hardangervidda did not show any trend in egg volume in relation to the start of egg-laying. On Jaeren more late than early Golden Plover clutches contained fewer than 4 eggs. On Hardangervidda no reduction of clutch size with season was found in either Golden Plover or Dotterel. In newly hatched Dotterel chicks both body weight and tarsus length were positively correlated with egg volume, while no such data were collected for Golden Plover. It is argued that, in waders, populations of single-brooded species should show a decrease in egg volume with season, whereas this should not apply to multi-brooded species.