Domestication effects on foraging strategies in fowl

Birds of two different breeds differing in degree of domestication were stu died to reveal any differences in foraging strategies between them. The bre eds were wild-type birds (crossing between red jungle fowl (Gallus gallus) and Swedish bantam (Gallus gallus domesticus) and domestic birds (Swedish b antam)), breeds representing an increasing level of domestication. Bantam b irds have not been selected for any specific characteristics. The birds wer e allowed to forage in an experimental pen containing two separate food pat ches, which depleted as a function of being exploited, to see how well the different breeds were able to assess costs and benefits as the distance bet ween patches were changed (short distance between patches compared to long distance between patches). Both breeds behaved in accordance with some gene ral predictions of optimal foraging theory, i.e. moved between patches, lef t patches before these were empty and stayed for a shorter time in more dep leted patches. Wild-type birds responded more than domestic birds to an inc rease of distance between patches, by spending longer average time in patch when there was a long distance between them compared to when there was a s hort distance. The wildtype birds adopted what seemed to be a more costly f oraging strategy, moving more between patches than the domestic birds witho ut ingesting more feed. During domestication, in the protected environment provided by man, individuals using less costly behavioural strategies may h ave gained increased fitness over those spending more energy on foraging. A lthough domestic birds still possessed the ability to respond adaptively to environmental conditions, the differences between the wild-type and the do mestic breed might be a result of the reduction of the natural selection pr essure which accompanies domestication. (C) 2001 Elsevier Science B.V. All rights reserved.