Foraging Habitats of Female Common Snipe Gallinago gallinago During the Incubation Period

Abstract

SUMMARY (1) The ranging behaviour of ten radio-tagged female common snipe Gallinago gallinago L. breeding in lowland wet grassland was studied during the period when they were incubating their eggs. Feeding sites were identified by radio-tracking and the diet investigated by faecal analysis. The timing and duration of absences of four females from their nests were established by automatic monitoring of the signal from the radio-tags. (2) Female snipe incubated their eggs without assistance from their mates. They left the nest for short periods (mean 15 min) during daylight and were absent from the nest for 22% of the time. The proportion of time spent away from the nest increased with increasing ambient temperature. (3) There were individual differences in the type of habitat used for feeding and the distance of feeding sites from the nest. Some birds fed in unflooded meadowland, usually near the nest, and others moved to wetter areas at the edges of pools and ditches. Snipe walked from the nest to feeding sites within about 70 m and flew to more distant sites. (4) Snipe fed on earthworms, insect larvae and snails by probing with the bill in soil and mud. They fed to a greater extent at the edges of ditches and took a greater proportion of insect larvae and snails in a year in which there was prolonged surface flooding compared with a year with less flooding when they mainly fed on earthworms in meadowland. (5) Both the density of invertebrates and the force required to probe the surface soil influenced the use of feeding sites near the nest. Females fed near their nests in unflooded meadowland, in areas with a moderate biomass density of soil invertebrates and surface soil that was easily probed. They fed in wetter habitats further from the nest if the invertebrate density near the nest was low or if the soil surface had dried out and was difficult to probe.