Life history of the Japanese Greenfinch Breeding biology 1

Abstract

1. This study of the breedingbiology of Japanese Greenfich Chloris sinica minor was conducted during March 1966 and August 1968, in an area of 660 ha of farmlands in Nagano prefecture, 400 m of altitude.
2. The study is based on breeding records of 262 nests, eleven all-day observations on breeding pairs and 824 marked individuals.
3. The breeding procedure cousisted of five periods: preparatory-nest-building-egg-laying-incubation-chick-raising and famiy-life periods.
4. Pair formation is advanced through the male's series of behaviors which are: courtship song-coutship posture to an attracted female-leading the female into a selected nest-tree-following after the female. After pair is formed the female selects the nest site.
5. When the female fails to find the nest site within the male's territory, she would wander out of it for seardh of a good site, fllwed by the male. Therefore, the first territory is abandoned.
6. Early in the breeding season, before middle April, they work for nest-building only in the morning and diappear in the afternoon to join the flock.
7. The female only builds the nest and the male follows her closely.
8. The nest-building period varies from about 14 days in the earlier part of the season, before 5 April, to as short as 4 days after entering May.
9. This is due to the situation that in early season they feed on seeds left from the previous year and need time in foraging, their nest-building and egg-laying are prolonged. Later in the season, they can efficiently feed on rich source of new grass seeds and therefore finish neting in a short time and lay eggs at onde.
10. The egg is usually laid one each day early in the morning. There were three exceptions (out of 68 caseg) in which eggs were laid in less than 24 hours.
11. Day incubation is commenced after laying the first egg of clutch but true or night incubation sets in after the clutch has been completed.
12. The female only incubates and is fed by the male. This feeding is usually (76.9%) performed at exposed places outside of the nest (The female may remain to be fed in the nest when she is conscious of observer) and never in the nest-tree. The feeding spots are concentrated along the territory border 20-40m from the nest and at least 8m it. Judging by the observer's personnal experience this has advantage to protect the nest from predator.
13. The incubation period varied between 12 and 15 days but 40.6% were 12 days and 46.9 % 13 days.
14. A clutch hatched in 1-3 days, with 89.4% in 2 days.
15. Both sexes engaged in feeding the chicks and the frequency was 11 times a day This very low rate as compared with those in insect-eating passerines is due to the presence fo the crop in which the parents carry and chickc store the food.
16. The chicks' growth of body weight slown in later stage and slightly decrease before nest-leavin, but the quills grow continuously. The tail is still short on flying.
17. Teh feeding period of nestlings was 12-17, usually 14-15 (51.7%), days. After flying chicks were fed by both parents for 7-10 days and a few pairs commenced the second brood.