Do male Nuthatches (Sitta europaea) guard their mates?

Abstract

Summary We expected to find a clearly manifested mate guarding behaviour in males of Sitta europaea as males of this socially monogamous species participate extensively in parental care. We recorded behaviour of nuthatches during one breeding season in primaeval stands of the Biatowie±a National Park (E Poland) anticipating that in the females' fertile period the males would stay in close proximity to females and would follow them. We compared the amount of time spent in close proximity, distances between pair members and following rates in the pre-fertile, fertile and post-fertile periods. We also quantified the male contribution to parental care. The males invested heavily in parental care; they regularly fed the incubating females (median = 8 feedings/hr) and provided most food for nestlings (median = 71% of feedings). In the fertile period, compared to the pre-fertile period males did not spend more time in close proximity of females, they moved away from the females even more frequently. They followed their mates at low rates, and often with a latency exceeding 30 s. It was more a case of the female trying to keep contact with the male especially during breaks in the incubation, than vice versa. None of the mate guarding predictions was thus supported by our data. We suggest that the combination of elaborate copulation ceremony of the nuthatch (which makes clandestine copulations difficult), the impeded mobility of females, and the benefits to females of food provided by males provided sufficient paternity assurance mechanisms in the nuthatch.