Winter Food Habits of Grey-headed Green Woodpeckers Picus canus

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Fecal droppings of Grey-headed Green Woodpeckers, which were left in roosting nest boxes, were collected and analyzed from 20th October 1977 to 9th April 1978. The nest boxes were set up on the Forest Observation Tower in the Tomakomai Experiment Forest of Hokkaido University.(1) Food items identified were insects, spiders, centipedes and plant food (seeds of trees).(2) Results of the dropping analysis were expressed according to the subdivision of seasons in the Experiment Forest. Lasius niger was favored from Autumn to Winter I, then decreased inWinter II, and increased in Late Winter again.(3) Many seeds of trees appeared in Autumn to Winter I but they decreased in Winter II and did nor increase thereafter.(4) Animal foods other than ants increased in Winter I; in Winter II only spiders increased.(5) We discussed the questions of analysis of droppings and the relation between the food habits of Grey-headed Green Woodpeckers and snow depth.
日本鳥学会の論文