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SEASONAL VARIATION IN THE FOOD OF THE PURPLE MARTIN PROGNE SUBIS IN KANSAS
Author(s) -
Johnston Richard F.
Publication year - 1967
Publication title -
ibis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 80
eISSN - 1474-919X
pISSN - 0019-1019
DOI - 10.1111/j.1474-919x.1967.tb00002.x
Subject(s) - moulting , biology , variation (astronomy) , geography , zoology , ecology , larva , physics , astrophysics
Summary Stomach contents of 34 Purple Martins Progne subis and 90 netted samples of flying insects were analysed taxonomically and quantitatively and compared with one another. Insect food sources tend to become more abundant, taxonomically variable, and larger in size late in the season (August). Maximal availability of food thus coincides with maximal energy requirements of Purple. Martins, which then are at peak numbers, initiating moult, accumulating fat and beginning migration.