Marjorie Sorensen and her international team of collaborators have just published a paper in Ecology and Evolution asking whether longer bird migrations are associated with increased blood parasitism, by exposing birds to a greater variety of parasites. Marjorie and team used stable isotopes to estimate the migration distances of willow warblers wintering in Zambia, and found that this was unrelated to blood parasitism or other indices of health and condition, suggesting that other factors might be more important in determining individual susceptibility to disease in migratory birds.
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.