Hebda G., Wesołowski T. 2012. Low flea loads in birds’ nests in tree cavities. Ornis Fennica 89: 139-144.

High flea (Siphonaptera) loads are typically found in birds’ nests in nestboxes. Ten years of observations, involving Marsh tit Parus palustris, Great Tit Parus major and Blue Tit Parus caeruleus, nests in tree cavities in primeval forests of Białowieża National Park, Eastern Poland, demonstrated that the prevalence of fleas was below 10% of nests and that the intensity of flea infestation was low. Low flea loads may be typical for nests in tree cavities. Therefore, nest-box data about flea-host interactions should not be treated as representative for conditions in natural cavities.