ホシガラスとアマツバメの食物分析

抄録

Analysis of contents of 39 stomachs of Nucifraga caryocatactes japonicus and 14 of Apus pacificus kurodae of Japan, formerly collected and preserved by late Mr. J. Ishizawa, are reported, as one of the series of studies based on his material kindly given to the author.
1. The nutcracker consumed far more amount of Pinus pumila seeds than other items in number and frequency, especially in February and March when the seeds are younger. The ptarmigan of the same area prefers older seeds and its suggested relation with the nutcrackers that it makes use of the latter's stored seeds is untenable. 15 animal items, including a Microtus and a Hyla, were identified and Curculionidae outnumbered others among insects.
2. The swift's diet consisted of 92% Formicidae, followed by Ichneumonidae 57%, Vesperidae and Elateridae 28% each. In the insect Orders, frequency % were: Hymenoptera 92%, Coleoptera 57%, Hemiptera 21%, Orthoptera 14% and Diptera and Lepidoptera 7% each.