BIRDS OF LAKE TOUFUTSU

I. WADERS

Abstract

Observations were made on waders at Lake Toufutsu, situated in the eastern Hokkaido, from 1972 to 1975. This lake is of a brackish water by connecting with Okhotsk Sea at the north-west end. Here visit numerous birds in spring and autumn, and a total of 32 species of waders were recorded by this study. This figure is greater than that in Mukawa-river (Kobayashi et al, 1975).
Waders were observed at various habitats which were divided as follows:: a) in the water far from shore. b) mud flat, c) lake-shore. d) in the marshaland near shore. Two phalarope species and two godwit species (Limosa limosa and L. lapponica) occurred frequently in habitat a), but the former was observed in the pond near lake-shore, and the latter in the water over 2 m apart from shore-line. 21 species were observed on the lake-shore, while 19 species were recorded on the mud flat. Tringa ochroppus, T. glareola, Gallinago gallinago and G. hardwickii frequented the marshland behind the lake-shore, but often appeared on the latter for feeding.
Waders began to appear from mid-August, and the number of species rapidly increased from late August to early September. The number decreased fastly to the 19, October, but increased again thereafter.
Percent of occurrence of species showed seasonal changes. Calidris ruficollis was most abundant each month and Charadrius mongolus and Calidris alpina was next commonest.