Bijdrage tot de biologie en de ecologie van den spreeuw (Sturnus vulgaris vulgaris L.) gedurende zijn voortplantingstijd

In February, March and April starlings fed in a flock on the fields near nestboxes. At night they roosted together in thousands in the reeds of a pool, 5 km from the nestboxes. In February or March each♂occupied a particular nestbox. Early in the morning they left the flock, and stayed and sang by the nestboxes for 10-30 min., then returned to the flock but returned soon. The♀visited the nestbox a few weeks later. The♂had then already started building the nest.Later the♀largely completed it. The nests consisted of straw; during the breeding period they were lined with feathers.The♂more often brought food to the young than the♀. An aphisigraph was used to record the number of feeds brought to the young. To determine the food of the young quantitatively and qualitatively a closely fitting collar of aluminium was placed round their necks for 4 h a day, so that they could not swallow the food. This food was removed from the oesophagus with forceps or from the nest if the young had already rejected it. The food consisted almost entirely of animals. Among 17.933 deliveries there were at least 313 species, among which 267 insect species. Earthworms were only found in minute quantities. Carnivorous arthropods formed 30 % of the food. Although plots with many Tipula larvae were more often visited by the starlings than those with fewer larvae, a colony of starlings had little influence on the population of Tipula paludosa