日本産ホトトギス科4種の食性

抄録

The stomach contents of 82 Cuculus canorus telephonus, 56 C. saturatus horsfieldi, 59 C. p. poliocephalus and 22 C. fugax hyperythrus, 213 in total, were analysed. These material had been collected by sinior author (Ishizawa) from 14 prefectures in Japan during more than ten years since about 1925 while he was in Wildlife Bureau. For identication of Lepidoptera larvae most frequently found in the stomachs, he studied them in the field and laboratory during 1931-1950 and published three books on these difficult insects to identify. Most of Lepidoptera larvae could thus been identified correctly by the sinior author, but other insects were identified by specialists.
Analysis of stomach contents were made by junior author (Chiba). It was found to be a characteristic food habit of cuckoos that a certain species of larvae was taken in large quantity at a time, only very few of others mixed with. Lepidoptera larvae occupied 91.3% of diet (frequency) in canorus, 90.0-90.3% in saturatus and poliocephalus and 86.3% in fugax which was characterized by prefering ants (Formicidae) with the relative frequency of 73.6%. Insects other than Lepidoptera were 81.8% in fugax, 45.6% in canorus, and 30.0-30.6% in saturatus and poliocephalus. There-fore from the food preference pattern, canorus-type, saturatus-poliocephalus-type and fugax-type may be recognized.
Among Lepidoptera, Geometriidae larvae occurred constantly 25-36% in the four species, Notodontidae varvae 23.4-38.0%, except in fugax in which they were only 4.5%; while Limantriidae larvae occurred 22.7% in fugax and 2.0-15.5% in the others. Sphingidae larvae were favoured by saturatus, Arctiidae larvae by canorus; Orthoptera were often eaten by saturatus, Formicidae were especially taken by fugax and relatively by canorus and poliocephalus, which ate also Odonata and Diptera. Cicadidae with 'bad' smell were not rejected, but were not found in poliocephalus.
There was a seasonal change of diet and stomachs contained less quantity towards autumn before migration.