Honeyguides and other brood parasitic birds are famous for tricking host parents by laying eggs that mimic their own. Honeyguide eggs mimic host eggs in size yet, surprisingly, bee-eater hosts are undiscriminating and readily accept mismatched eggs. This study shows that honeyguide egg size adaptation has probably rather evolved to trick other honeyguides, not host parents: honeyguides selectively puncture any mismatched egg already present in the nest when they lay their own, lest it be the offspring of another honeyguide female and brutally kill their own chick when it hatches.
Read the full paper in Biology Letters [Open Access], or Ed Yong’s excellent article about the study. Here are some other nice articles and podcasts online covering this study: The Behaviour, Ecology & Evolution Podcast | Take Part blog | Earth Times.
New paper on imperfect egg mimicry
Our paper “Combined measures of mimetic fidelity explain imperfect mimicry in a brood parasite-host system” has just been published in the journal Biology Letters. This study was led by Tanmay Dixit, and carried out together with Gary Choi, Salem al-Mosleh, Jess Lund, Jolyon Troscianko, Collins Moya, L Mahadevan, and Claire Spottiswoode, as part of a collaboration between our group and Prof. Mahadevan and his lab at Harvard University. Together we combined mathematical tools and field experiments in Zambia to quantify a key difference – “squiggle” markings – between the eggs of hosts (tawny-flanked prinias) and parasites (cuckoo finches). We showed that suboptimal behaviour on the part of prinias allows cuckoo finches to get by with an imperfect copy of prinia eggs.