Breeding ecology of Spizaetus nipalensis in Japan
1. Nesting behavior
1971 Volume 6 Issue 3 Pages 286-299
Details
1971 Volume 6 Issue 3 Pages 286-299
1. Breeding behavior of the Japanese Hawk Eagle Spizaetus nipalensis japonensis was studied for 12 years, 1957-1969, in the mountain ranges mostly below 1, 000m of altitude, from Mt. Nijyo to Mt. Izumikatsuragi(with the ridge area of ca. 40×1km), in Mt. Kongo and Mt. Izumi, along the prefectural borders of Osaka, Nara and Wakayama.
2. Here, the observations during early nesting stage are reported and analysed based on 19 nest records.
3. The nesting behavior occurred from as early as late January or early February.
4. The nest is completed by average 30 days and if damaged by snow or winds the second one is renested again by about 30 days.
5. Eleven of the 19 nests observed were newly built and old nest was repaired in four cases and in one example a complete new nest was built on an old one.
6. There were three types in nest-site in 18 nests recorded, near tree-trunk type (7, 38.9%), tree-top type (4, 22.2%) and out on branch type (7, 38.9%). The branch type seems to be characteristic to this species.
7. The nest size was 80-150cm in diameter and 25-85cm deep and chief nesting material were dead twigs of red pine, the largest one measuring 3.5cm in diameter and 110cm long. Some twigs with green needle-leaves of red pine, Japanese cedar, Japanese cypres or Pinus pentaphylla are placed on the nest.
8. The nest was usually found at about the middle of the mountain bight, between 250m to 600m (av. 450m) above the sea level.
9. The most nests, 84%, were built in Japanese red pine wood, 5% in cryptomeria plantation and 11% in mixed woods of red pine and hinoki. One nest was as close as 150m to a human house.
10. The nesting tree was at least 39cm in diameter at man's breast hight and 5m tall, and 49% of nests were on red pine with 6% on cryptomeria.
11. The nesting location was usually at a lower part of the mountain slope where there were bigger trees fitted for nesting. But no preference of wood edge or inside was noticed.
12. The change of nest site of the same pair (probably) by year was average 590m, and 75% of nests were located in the same wood. In one area, 8 nests were found during 12 years, the 6 of which having been located in a same wood. The distances of two nests in other wood were 1.500m. 800m and 600m.
