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THE EXPERIMENTAL REGULATION OF ZUGUNRUHE AND THE SEXUAL CYCLE IN THE BRAMBLING FRINGILLA MONTIFRINGIUA
Author(s) -
LOFTS B.,
MARSHALL A. J.
Publication year - 1960
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.1960.tb07113.x
Subject(s) - gonad , biology , photoperiodism , development of the gonads , day length , period (music) , zoology , endocrinology , physics , acoustics , horticulture
SUMMARY 1. Bramhlings of both sexes, including young males, failed to show significant gonad enlargement or to develop spring Zugunruhe during the normal migratory period while artificially kept under winter day‐lengths. 2. When the photoperiod was suddenly changed to 14 1/2 hours (equalling mid‐April day‐lengths) nocturnal unrest became apparent in all birds within three days, even though the normal migratory period was now past. 3. This temperate‐zone, spring‐breeding migrant therefore does not come rhythmically into breeding condition as do the young of the xerophilous Budgerygah and Zebra Finch. 4. Concurrently with light‐induced Zugunruhe there occurred a striking fat deposition and, in the adult males, a minor gonad enlargement. A separate experiment involving the photo‐stimulation of castrated adults tends to suggest that Zugunruhe (and therefore possibly migration) can occur in the absence of sex hormones but the regeneration of a single gonad in one of the castrates rendered the results inconclusive.