Zur Ernährung und Nahrungsëkologie des Dreizehnspechts Picoides tridactylus während der nestlingsperiode

Food and foraging ecology of the Three-toed Woodpecker Picoides tridactilus during the nestling period.

During the nestling penod of 1994, the food of one pair of the Three-toed Woodpecker in Berchtesgaden National Park was investigated by the analysis of 38 neck-collars samples, 124 faecal droppings and by radio-lelemetry. In total, 39 prey species were found, belonging to 18 families and 10 orders. The most important food items were larvae of long-horn beetles Rhagium sp., mostly Rhagium inquisitor, and spiders (Araneidea). The different methods yielded similar results. A comparison of the nestling diet with the diet of adults showed that for young of lhe Three-toed Woodpecker bark-beetles were less imponant than for adults. The feeding strategy may be different if aduts feed their chicks or if they feed themselves. During the nestling period the young increased their weight about four-fold. The adulls foraged mostly on dead bur still standing spruce trees. The male used decayed wood more often lhan the female. The distance between lhe nest-hole and the foraging grounds measured up to 1.5 km.