The Role of Search Area in the Detection of Cryptic Prey by Crested Tits and Coal Tits

The probability of perception of prey may depend on the previous experience of the predator, its expectations and its search tactics. In this study we investigated the role of the search area. Based on previous results and on known facts about foraging ecology, we hypothesised that crested tits (Parus cristatus) would perform better when searching larger areas for cryptic prey compared with coal tits (Parus ater) that have been found to search small areas for cryptic prey more successfully. In our experiments these two tit species were required to search for cryptic prey in large and small dishes. Both species detected cryptic prey less frequently in the larger dishes, however, crested tits performed better initially. Coal tits improved over time. Both species needed more time for detecting prey in large dishes, and crested tits searched longer in small dishes than coal tits. Giving-up times, when no prey was found, also reflected these differences. The results suggest that the tits search with speciesspecifically set search areas and 'time windows'. It also appeared that coal tits are more flexible in adjusting search to a given situation.