On the distribution and migration of <i>Locustella o. ochotensis</i>

DOI Web Site 2 Citations

Bibliographic Information

Other Title
  • シマセンニユウの分布と渡りについて
  • シマセンニュウ ノ ブンプ ト ワタリ ニ ツイテ

Search this article

Abstract

This paper is based on 141 'light-house struck specimens'of Locustella o. ochotensis, sent to the writer from the following 17 light-houses since 1924: Kuriles (Kunashiri), Hokkaido (Erimo, Chikyu, Esan), Aomori (Hiradate, Oma, Shiriya), Akita (Nyudo), Chiba (Nojimazaki), Shizuoka (Omae), Wakayama (Hinomisaki), Shimane (Jizo, Hinomisaki), N. Kiushiu (Eboshi), S. W. Korea (Takeshima, Shichihatsuto) and Formosa (Fukikaku). Other specimen and sight records from Yamagata, Niigata, Saitama, Tokyo, Toyama, and S. Korea were also considered. Chief points are as follows:<br>1) This less-known species passes Japan chiefly in June and late August to October. 2) The spring migration period (early v-vi) is much shorter than that of the autumn (late viii-xi). The breeding period is short (early vii-mid-viii) and the wintering period is five months (xii-iv). 3) The reason for more records in the autumn than in spring should be the tripled post-breeding population and high ratio of young bird accidentals. 4) Distinctly, the migration is heavier on the Japan Sea side than on the Pacific coast of Honshiu, and suggested three migration courses are: firstly, the well-known Philippine-Formosa-Riu Kiu course; secondly, the newly proposed one of Philippine-Formosa-China coast-S. Korea (across the Yellow Sea)-N. Kiushiu; and thirdly, continental course passing Ryojun (Port Arthar). The second is the chief route of this species. 5) More males (4 out of 5) than females were passing Cape Shiriya in early June (the 8th), which was reversed (6 females out of 7) in middle June (the 16th), and no male was included on the 27th. During this period, the measurements of the gonads of both sexes increased (faster in the males). 6) Three fat classes of amount were identified. In spring specimens, there was excess deposition of fat which is reserved to be used as energy for postmigration breeding. In the autumn, the fat was much less, and was more so in the young birds. 7) Both the rate of gonad development and amount of fat were rather constant among the birds of the same flock, but were different by flocks, irrespective of the advance of the season.

Journal

Citations (2)*help

See more

Details 詳細情報について

Report a problem

Back to top