A simple technique to manipulate foraging costs in seed-eating birds

Egbert Koetsier, Simon Verhulst*

*Bijbehorende auteur voor dit werk

OnderzoeksoutputAcademicpeer review

25 Citaten (Scopus)
231 Downloads (Pure)


Food availability is a key factor in ecology and evolution, but available techniques to manipulate the effort to acquire food in vertebrates are technically challenging and/or labour intensive. We present a simple technique to increase foraging costs in seed-eating birds that can be applied with little effort and at low monetary cost for prolonged periods ( years) to solitary or group-housed animals. The essence of the technique is that food is offered in a container above ground level, with holes in the sides from which the food can be taken, forcing birds into energetically demanding hovering flight to forage. As a control treatment we offered a similar container but with perches mounted beneath the holes, allowing birds to eat without extra flights. Increasing foraging costs in this way induced zebra finches to double the time spent foraging, and to decrease their basal metabolic rate, in agreement with results obtained using more laborious techniques to increase foraging costs. The technique was not too severe because mortality was low during a winter with sub-zero temperatures. As foraging costs under natural conditions are generally higher than those under standard laboratory conditions, we suggest that measuring behaviour and physiology when animals have to work for food may better reflect their natural state.

Originele taal-2English
Pagina's (van-tot)1225-1229
Aantal pagina's5
TijdschriftJournal of Experimental Biology
Nummer van het tijdschrift8
StatusPublished - apr-2011

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