Ingestion of Snow and Ice by Pileated Woodpeckers and Northern Flickers

Abstract

Although on occasion pileated woodpeckers (Dryocopus pileatus) and northern flickers (Colaptes auratus) drink water from puddles or other sources (Kilham 1983; Bull and Jackson 1995; Moore 1995), obtaining water by eating snow and ice is apparently unreported for these species (see Bent 1939, Bull and Jackson 1995, Moore 1995). Here I report on observations of a female pileated woodpecker eating snow and a female northern flicker eating ice, and speculate on the significance of this behavior by birds living in areas where water in a liquid phase may be unavailable for several days or weeks. On 13 January 1978 I was walking in Hellgate Canyon, just east of Missoula, Missoula Co., Montana (46° 52' N, 113° 59' W). At 1300 MST I watched a female pileated woodpecker swoop down from a wooden power line pole to a snow-covered log about 30 m from me; about 6 cm of granular snow covered the surface of the log and most of the ground. In the next 60 sec the woodpecker ate 9 bill-loads of snow (scooping up each load while keeping the side of its head nearly parallel to the snow surface). The bird then flew back to the pole before flying into the woods out of view. Although the site where the observations took place was near the Clark Fork River, most of this reach of the river was frozen at the time, and accessible free water in a liquid phase appeared rare. Ambient temperature at the time was-1°C. For several days preceding and following the day of the observations, the daily maximum was 5% of total body weight for medium-sized and large woodpeckers, and much greater for smaller passerines (see discussions in Bartholomew and Cade 1963; West and Norton 1975; Marsh and Dawson 1989). Heating fro-