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Experiments on single diving birds in the laboratory often measure dives of decreased effort
Author(s) -
HALSEY LEWIS G.,
BRAND OLIVER J.,
WOAKES ANTHONY J.,
BUTLER PATRICK J.
Publication year - 2006
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.2006.00476.x
Subject(s) - ornithology , library science , biological sciences , art , art history , biology , computer science , ecology , computational biology , southern hemisphere
There have been a large number of laboratory experiments investigating the diving behaviour of Tufted Ducks Aythya fuligula (e.g. Butler & Woakes 1979, Woakes & Butler 1983, Houston & Carbone 1992, Halsey et al . 2005a). This species is common, hardy and adapts quickly to the laboratory environment. Thus, it is often the diving species of choice for testing hypotheses on the physiological and behavioural adaptations of divers to underwater foraging. To our knowledge, all previous investigations have studied birds diving alone, whereas in the wild Tufted Ducks are usually found in groups ranging in size from four or five birds to many hundreds. Therefore, under natural conditions they are usually competing with conspecifics for food. Because food is a finite resource, a Tufted Duck might be expected to attempt to maximize the proportion of the food that it ingests relative to that taken by conspecifics. However, in the experimental dive tank, a solitary diving duck may recognize that it does not have to compete with others for the available food. This raises the question of to what degree the behaviour of a single bird while diving in a laboratory setting differs from that of many birds diving together. The most straightforward way to measure changes in diving behaviour is to record the time budget data of the dives (e.g. Houston & Carbone 1992, Halsey et al . 2005b). In the present study, the dive time budgets of Tufted Ducks diving alone or with conspecifics in a laboratory setting were measured to test whether diving behaviour differed under these two conditions. We hypothesized that Tufted Ducks diving in the dive tank with conspecifics would forage more intensively than Tufted Ducks diving in the dive tank alone. Furthermore, the diving behaviour of Tufted Ducks diving in the wild was observed to see whether the behaviour also differed in a natural setting between when diving alone and when diving with conspecifics. METHODS