CORN STOCK AND WINTERING OF THE COMMON CRANE (GRUS-GRUS) IN SOUTHWESTERN FRANCE

The influence of distribution and abundance of food (maize) on Common Crane behaviour and distribution patterns in time and space was analysed in the farmlands of south-western France. The maize stock most likely to be exploited by cranes gradually decreases from November to March because of autumnal germination, seed mass loss during winter, and burial during tilling of the soil. The variation of crane numbers over time does not depend on seed stock changes. The feeding behaviour of these birds does not change with decreasing seed availability, whereas gregariousness increases. The plots most likely to be selected by cranes offer accessibility to seeds and the best food supplies: crushed maize, in the first instance, and when this is not available, pulverized maize. Feeding behaviour and gregariousness do not vary with plot quality.