Abstract
Number of House Swallows Hirundo rustica (gutturalis) was counted on their rout of roosting flight through a same window-mesh during post-breeding and departure period in three seasons, 1959, 1960 and 1961, in Saga, Kiushiu.
The roosting flight was direct and low and began from 90 minutes (with the peak 30-15 min.) before sunset and with seasonal peak in September towards the end of which month they departed. The numbers were greater on fine calm days and markedly dropped when disturbed by typhoons.
This roosting flight seems to have been established after the use of insecticides on the plain, since the swallows now mostly move to the hill-side for the day feeding to return to the roost of low land in the evening.
