This is the result of a year research on the breeding ecology of
Microsarcops cinerea (Blyth), made during May, 1955 and May, 1956 in Kyoto and Mie, the first breeding evidence from western Honshu (first suggested by Mr. J. Kikkawa).
The descriptions of the adult, juvenals and chicks, the field identification, and the sight (since 1951) and breeding (1955, 1956) records in Mie, Kyoto and Shiga, are given. It prefers wet fields, living in winter in flocks of 5-50 birds, but breeds by pairs territorially. In Ogura, Kyoto some 30 pairs breed and winter within an area of 700 Chobu (648 ha). They nest on the ridges of cultivated paddyfields, often close to the paths, but rather apart from each other, the shortest distance 250 m. When an intruder approaches within about 100-200 m. from the nest, the male tries successive attacks (most violent when they have youg chicks) against him/it utterring sharp notes, helped by the males of the adjacent territories. But, even these helpers are attacked when they come too close to that nest. Many nests are damaged by farmers who cultivate the field once or twice during April and June, thus they often renested near the former nest (once as close as 7 m.). The egg-laying season is from middle March to late May; 4 eggs but often 3 in case of renesting, the incubation period being 27-30 days. Individual variation is found in the nest (straws mixed in fertilizer are used) and egg arrangement (see photos). Injury-feigning is chiefly done by the male, a bird led the author about 80 m. whene it was attacked by the other male of the adjacent territory. Known and newly examined food items are finally given.
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