Oregon junco foods in coniferous forests

A food analysis was made from the gizzard contents of 262 Oregon juncos(Junco oreganus) collected in western Oregon from 1954 through 1962. Theaverage annual diet was about half seed and half insect material. Juncosate the seeds of many plants and also some germinants (sprouting seeds, andseedlings with seed coat on the cotyledons); those of Douglas-fir (Pseudotsu-ga menziesii), blackberry and raspberry (Rubus spp.) and hawkweed (Hier-acium albiflorum) were the most important. A great variety of insects wastaken but ants (Formicidae), snout beetles (Curculionidae), ground beetles(Carabidae), and leafhoppers (Cicadellidae) comprised the greatest volume.Douglas-fir seeds and germinants were an important sought-after junco foodaveraging 12%. They represented a trace in seed failure years, 6% in lightseed years, and 32% in moderate to heavy seed years. Hemlock (Tsuga spp.)averaged only 1% of the food, even though it was a consistent seed producer.Seeds of redcedar (Thuja plicata) were not taken. Destruction of Douglas-fir seeds and germinants by juncos should be considered when evaluatingfactors that may hinder regeneration.