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“NONSENSE” ORIENTATION IN MALLARD ANAS PLATYRHYNCHOS AND ITS RELATION TO EXPERIMENTS ON BIRD NAVIGATION
Author(s) -
Matthews G. V. T.
Publication year - 1961
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.1961.tb02435.x
Subject(s) - orientation (vector space) , anas , captivity , flock , fledge , pecking order , seasonal breeder , zoology , geodesy , geography , biology , ecology , geometry , mathematics , hatching
Summary A strong tendency in non‐migratory Mallard to fly N.W. on release is described. This orientation is shown regardless of distance and direction of release, of season or of length of captivity. It is shown at any time of day by birds of both sexes and of all ages, and is unaffected by the topography of the release site. Head winds of moderate strength impart a wider scatter, otherwise winds have little effect. It appears to be a sun‐compass orientation. The orientation breaks down, probably quite quickly, and is replaced by random wandering. There are no indications of true navigational ability. It is suggested that the orientation may function to keep flocks together and be related to the northward post‐fledging movements of many birds. The existence of such a strong orientation and its presence in another non‐migratory bird, the pigeon, is considered to have caused confusion in experiments on navigation undertaken with the latter. Results obtained with pigeons in N. Carolina and Germany can no longer be considered conclusive. The conflict of their results with those obtained in England is resolved.