Playback attracts prospecting individuals, but habitat quality is key for settlement in the wryneck Jynx torquilla.
Abstract
Organisms do not only use personal but also social information for habitat selection. However, the use and relative importance of these two sources of information for settlement decisions remain unclear for many species. Conservation tools that attract target species to available or restored habitat rely on social information, while additional or interacting effects of personal information may limit their efficiency. Here, we investigated the effects of food availability (individually acquired personal information) and conspecific vocalization (social information) on habitat selection of a regionally endangered, migrating woodpecker, the Wryneck Jynx torquilla. First, we analysed the species' occurrence in relation to food availability and habitat characteristics in general. Then, we conducted a playback experiment, during both the prospecting period and the breeding period, in previously unoccupied plots with different conditions of food availability to disentangle the relative importance of food availability and conspecific vocalization for habitat selection during both the prospecting period and the breeding period. Wryneck occurrence increased with food availability (i.e. ant nest density) and slightly related to food accessibility (i.e. the proportion of bare ground). Food availability varied considerably among habitat types, with the highest values in vineyards and the lowest values in intensively managed grasslands. Within the experimental framework, high food availability increased the probability of both Wryneck prospecting and breeding. In turn, playback had a positive effect on Wryneck prospecting under poor but not favourable food conditions, but not on Wryneck breeding. Finally, playback did not exert a significant effect on breeding success. Practical implication: Both personal and social information seem to affect Wryneck habitat selection behaviour. However, food availability as individually acquired personal information of a habitat cue mainly influenced Wryneck settlement decisions that led to breeding. Consequently, playback as social information through a simulated conspecific social cue is a potentially useful tool for Wryneck conservation, and the risk of attracting Wrynecks into an ecological trap is minimal. Nevertheless, habitat quality, and in particular food availability, are more important and a crucial requirements for successful conservation management.