Japanese Journal of Ornithology
Online ISSN : 1881-9710
Print ISSN : 0913-400X
ISSN-L : 0913-400X
Volume 42, Issue 1
Displaying 1-4 of 4 articles from this issue
  • Yutaka WATANUKI
    1993 Volume 42 Issue 1 Pages 1-8
    Published: October 25, 1993
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
    Mortality of eggs and nest attendance pattern of male and female Adélie Penguins were studied in Lützow-Holm Bay, Antarctica. Twenty percent of eggs were deserted by parents and were taken by skuas soon after. Only four percent of eggs were lost from skua predation. In pairs relieving incubation routines successfully (coordinated pairs), females made the first foraging trips of 18.3 days after clutch completion, alternately males made the second trips of 10.6 days. Desertion of eggs and small chicks occurred when 1) females did not return from the first foraging trips and the mates deserted nests, 2) males did not return from the second foraging trips and the mates deserted nests or 3) males went to the first foraging trips. The males whose partners did not return from the first trips did not incubate longer than males of coordinated pairs in the first incubation spell, while females whose partners did not return from the second trips incubated twice as long as those of coordinated pairs.
    Download PDF (6939K)
  • Katsumi TAMADA, Yuzo FUJIMAKI
    1993 Volume 42 Issue 1 Pages 9-20
    Published: October 25, 1993
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
    Nest distribution, nesting sites, breeding periods, sexual organs and nutritive conditions of two species of crows, Corvus corone (CC) and C. macrorhynchos (CM), were studied during 1989 and 1990 in Obihiro and its surrounding areas in three types of habitats: residential areas with no wooded areas (RI); residential areas with woods (R2), and agricultural land (AL). Thirty seven CC nests and 8 CM nests were examined during the study. CC nested mainly in shelterbelts in AL and on road side trees in R 1 and R2. CM nested mainly in woods in AL and R2. Nest densities of both species were high in R2 and low in AL.•Distances between neighbouring nests were shorter in Rl and R2 than in AL. Though the breeding period, from nest-building to fledging, was about 100 days both in CC and CM, CC started to breed 18 to 24 days earlier than CM. The testes and ovaries of CC began to enlarge earlier than those of CM. Nutritive conditions did not vary during the year for either species, and no relationship between onset of breeding and body weight or nutritive condition was found. The discrepancy in onset of breeding between CC and CM is probably due to their different reactions to the same daylight condition.
    Download PDF (9921K)
  • Keisuke UEDA, Hroshi UCHIDA, Takashi MATSUDA
    1993 Volume 42 Issue 1 Pages 21-25
    Published: October 25, 1993
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
    The Moorhen Gallinula chloropus is a well known intraspecific brood parasite.However, there has been no reports on brood parasitism of the Moorhen in japan. During a 8-yr field study of marsh nesting birds in Akigase marsh, central japan, we found some Moorhen nests which contained abnormally large number of eggs (super-normal clutch) and we obtained evidence of intraspecific brood parasitism and/or cooperative nesting. Moorhens were unable to distinguish between foreign (Japanese Quail and conspecific) and their own eggs. A proximate cause of frequent egg dumping may due to the high breeding density in the habitat. This is the first report on the egg-dumping in a Japanese population of the Moorhen.
    Download PDF (4580K)
  • Kazuhiro EGUCHI, Hisashi NAGATA, Satoshi YAMAGISHI
    1993 Volume 42 Issue 1 Pages 27-29
    Published: October 25, 1993
    Released on J-STAGE: September 28, 2007
    JOURNAL FREE ACCESS
feedback
Top