Seasonal Variation in Daily Activity of Gallinago hardwickii in the Breeding Season

Abstract

Seasonal variations in the daily activity patterns of Latham's snipe Gallinago hardwickii were studied along the lower reaches of the Tokachi River, eastern Hokkaido, from late April to late August 1984. During the study birds were counted along a 3km transect at a speed of 3km per hour and an intensive search was made for sitting snipe in a 1.4km2 area of riverbed. During the breeding season aerial displays were the . most conspicious behaviour, followed by calling from poles or trees. The number of snipes counted increased at 03:00, 06:00-07:00 and 19:00 in late April and mid-May, and also at 17:00 in late May and mid-June, showing 3 or 4 peaks. Peaks occurred just before and after sunrise or sunset. The maximum number of snipes counted in the daytime, between 06:00 and 07:00, increased from late April to May, then decreased gradually until the end of June. There-after the number of snipes observed declined abruptly because of the decrease in detectability and in numbers. Although censuses can be carried out from late April to late June, foran effective census it is desirable to survey snipes between 06:00 and 07:00 in May.