Pairs show similar risk taking behaviour but only female risk taking behaviour is linked to nest microhabitat choice in the Kentish plover

Abstract

Risk taking behaviour — how individuals perceive and respond to threat — varies among individuals. In birds, this behaviour influences the choice of nest microhabitat presumably because exposure to predation depends on the structural composition of the nest microhabitat (i.e., a small area where a bird builds its nest). Thus, a chosen nest microhabitat can indicate an adaptation to predation risk. However, where both parents participate in or share breeding roles, it is unknown whether the chosen nest microhabitat is influenced by risk taking behaviour of the female, the male or both parents. Moreover, risk taking may affect other behaviours during breeding, thus having a partner with similar risk taking behaviour may be important for pair complementarity. We investigated risk taking behaviour of breeding Kentish plovers (Charadrius alexandrinus) using flight initiation distance (FID) as a proxy. First, we tested whether FID is repeatable. Second, we tested whether members of breeding pairs have similar FID. Third, we investigated whether male and female’s FID is associated with the choice of nest microhabitat. We classified nest microhabitat by two indices: cover directly above the nest scrape (above nest cover) and cover around the nest (around nest coverage). We found that (i) FID was highly repeatable, (ii) FID was correlated within members of breeding pairs and (iii) female’s risk taking behaviour is linked to the use of around nest coverage. Specifically, females with longer FID, (i.e., more risk-averse ones) tended to use less concealed nest microhabitat. We concluded that nest microhabitat choice in the Kentish plovers is likely a reflection of the female’s risk taking behaviour. Breeding partners likely have similar risk taking behaviour, an indication of assortative mating. We advocate partitioning of correlation within breeding pairs to ascertain estimates of within pair correlation attributable to assortative mating.