Diet of Magpie (Pica pica) nestlings in relation to age and prey availability

Full article

Published:

Volume 39(1), June 1992. Pages 35-48.

Language:

Spanish

Original title:

Alimentación de los pollos de Urraca (Pica pica) en relación con la edad y disponibilidad de presas

Keywords:

availability, diet, magpie, nestlings, Pica pica.

Abstract:

The diet of magpie (Pica pica) chicks has been studied using the neck-collar method. Special attention has been given to the relationships between available prey and prey fed to the chicks. The importance of barley (11.4 % of total food) increased with chick age. The animal fraction included mainly adult Coleoptera (IG= 37.8) and larvae in general (IG= 16.2). The average prey size was 12.2 mm (SE = 0.28; n = 796), 68 % of which ranged between 5.1 and 15 mm. No clear relationship between prey size and phenology was found, although older chicks received a greater quantity of large prey. A correlation between prey fed to the chicks and available prey was significant only in two of 12 possible cases. Therefore we conclude that magpies select mainly larvae and spiders to feed their chicks. In addition, magpies tend to select prey larger than the average size of those available.