Prospecting in wild jackdaws (Coloeus monedula) : effect of breeding success, parental activity and timing

Abstract

Gathering information on potential breeding sites, a behaviour known as prospecting, can allow animals to select a breeding habitat of high quality and enhance their breeding success. Prospecting is particularly common in birds, where it can take the form of visits of a conspecific’s nest. Despite extensive research on prospecting in birds, there are still uncertainties regarding how breeding success, parental investment, and timing affect both the individual investment in prospecting and the attractiveness of a nest to prospectors. In order to investigate those questions, we conducted a large-scale study on western jackdaws (Coloeus monedula) using radio-frequency identification (RFID) technology. I found that prospecting increases over the course of the chick-rearing stage, reaches a peak after the fledgling of the chicks and subsequently decreases over time. Nestboxes where the breeding attempt failed received less prospecting visits during both periods (provisioning and post-fledgling stages). During the provisioning phase, nestboxes with a higher parental activity received more prospecting visits. Accounting for this effect, the number of fledglings did not influence the number of prospecting visits received by the nest. Finally, failed breeders prospected more than successful individuals and no trade-off was observed between parental activity and investment in prospecting (i.e. birds than invested more in parental care did not invest less in prospecting). Those results support the idea that the breeding failure of an individual induces an increased investment in prospecting. Furthermore, they show that parental activity is an important cue for prospectors. Moreover, the finding that jackdaws can discriminate between failed and successful nests even during the post-fledgling stage raises questions about the mechanisms at play (cues in the nest or memory). Overall, this study showed that breeding success influences prospecting in jackdaws in multiple ways and highlighted the importance of including the post-fledgling stage when studying prospecting.