J. Wright et Pa. Cotton, SONG VERSUS FOOD - TRADE-OFF DECISIONS IN A BREEDING COLONY OF EUROPEAN STARLINGS STURNUS-VULGARIS, Bird study, 41, 1994, pp. 95-101
A breeding colony of European Starlings Sturnus vulgaris was observed
every morning for a month prior to egg-laying. The whole colony was ei
ther involved in singing activity around the nest boxes, or feeding as
one big flock in fields. Switches between these 2 activities were sud
den and complete with it short intermediate stage when all the birds g
athered in a tight group on overhead electricity wires. The switches b
etween singing and feeding occurred approximately twice an hour, and l
ocal weather conditions had no apparent effect on these switches in be
haviour. As egg-laying approached, more time was spent at the nestbox
colony, with fewer birds feeding in the fields at any one time. Later
in the season longer initial periods were spent at the nestbox colony
before the first feeding excursions to the fields, resulting in fewer
switches between singing and feeding activities. The switches between
the 2 activities also became less distinct nearer egg-laying with the
flock breaking up into smaller units and feeding in fields closer to t
he nestbox colony.