A study of population density in the breeding season in Passer montanus in Hokkaido

1. This survey was carried out eighteen surveyed areas in Hokkaido in 1976 and studied the population density and the habitat of the Tree Sparrow (Passer montanus) in the breeding season.2. Population density was different in each surveyed area. The highest density was 714.3/km2 in Aonae, the lowest was 43.5/km2 in Koshimizu, and the mean of all areas was 273.1/km2.3. The surveyed areas were divided into groups which showed significant statical difference in population density. (Table 2)4. Population density in the breeding season correlated best with the number of houses which were used as nesting sites (r=0.625>r0.05). A correlation between the population density and the human population was also seen (r=0.488>r0.05).5. The Feeding area was in the vicinity of the house, and 100% in group I, 99.9% in group II, , 100% in group III, 96.2% in group IV, 96.0% in group V, and 88.2% in group VI fed within 50m of the house. (Fig. 4)6. In group I, feeding in the garden was most common (30.6%).In groups II and III, feeding in grassland was common (27.6% and 25.5%).In groups IV, V and VI, feeding in cultivated fields was common (31.4%, 21.8%: and 35.5%).7. A correlation between the surface area of the main feeding place and the number of birds visiting the place for feeding was seen (in Kotoni Town: r=0.936>r0.001, in Atsubetsu: r=0.747>r0.05, and in Oyafuru: r=0.644>r0.1).