Experimental evidence of reciprocal altruism in the pied flycatcher

• DOI: 10.1007/s00265-007-0484-1
• Publication Date: 2007-09-25T08:22:52Z
• Authors: Indrikis Krams; Tatjana Krama; Kristine Igaune; Raivo Mänd
• Keywords: 0106 biological sciences; 01 natural sciences

Although human behaviour abounds with reciprocal altruism, few examples exist documenting reciprocal altruism in animals. Recent non-experimental evidence suggests that reciprocal altruism may be more common in nature than previously documented. Here we present experimental evidence of mobbing behaviour, the joint assault on a predator in an attempt to drive it away, as reciprocal altruism in the breeding pied flycatcher (Ficedula hypoleuca). Given a choice, pied flycatchers assisted in mobbing initiated by co-operating neighbours and did not join in mobbing when initiated by conspecific neighbours which had defected from necessary assistance 1 h before. The results suggest the birds followed a ‘tit-for-tat’-like strategy and that mobbing behaviour of breeding birds may be explained in terms of reciprocal altruism.