Different tactics, one goal: initial reproductive investments of males and females in a small Arctic seabird

Abstract

Despite a great number of studies on extra-pair paternity in birds, the actual roles of males and females in extra-pair contacts is poorly understood, as detailed behavioural studies comparing the reproductive performance of the two sexes prior to egg laying are relatively scarce. Here, we investigated mating behaviour (copulations and aggressive interactions), time budget and body condition (size-adjusted body mass and baseline corticosterone level) in the little auk (Alle alle), a monogamous and highly colonial, Arctic seabird. We performed the study in a large breeding colony of the little auk in Hornsund (Spitsbergen). We found that the males frequently attempted extra-pair copulations (EPCs), although these contacts were almost always unsuccessful, mostly because of the females’ rejection behaviour. These results clearly indicate that genetic monogamy is maintained through female control. Nevertheless, males tried to protect their paternity by staying in close proximity to their females and aggressively intervening when their mates became involved in EPCs. Compared to females, males also spent more time in the colony guarding nest sites. Despite the apparent sex differences in the time budget and frequency of aggressive interactions, body condition was similar in the two sexes, indicating comparable parental investments during the mating period.

Rhinoceros Auklet pair‐mates migrate independently but synchronize their foraging activity during the pre‐laying period

“…, Wojczulanis‐Jakubas et al . ). Thus, there is a potential risk of extra‐pair fertilization for males.…”

“…Whether male alcids guard their mates at sea to prevent extra-pair copulation is unclear. Extra-pair fertilization is not common in alcids (Anker-Nilssen et al 2010), as in other seabird families (Quillfeldt et al 2012), but extra-pair copulation has been observed often in alcids (Birkhead et al 1985, Wojczulanis-Jakubas et al 2014. Thus, there is a potential risk of extra-pair fertilization for males.…”

“…For migratory species, synchronization or coordination of activity between mates after a return to the colony may facilitate their copulation and hence fertilization (Osorio-Beristain & Drummond 1998, Wojczulanis-Jakubas et al 2014). In the Procellariiformes, both mates regularly visit the colony during the pre-laying period but then leave again for a pre-laying exodus that varies among species from a few days to nearly 2 months (Warham 1990).…”

Assortative mating patterns of multiple phenotypic traits in a long‐lived seabird

“…Given the high genetic homogeneity of the global population of the Little Auk (Wojczulanis‐Jakubas et al . ) and the fact that we performed the study in a single colony, we assumed homogeneous distribution of the traits within the study population (i.e. pooling of mating pairs from heterogeneous samples might potentially lead to ‘false–positive’ results, Fernández‐Meirama et al .…”

Peer Review #2 of "How do colonial Eurasian Griffon Vultures prevent extra-pair mating? (v0.1)"

“…Based on the idea that females control the success of copulations, we can expect that in long-lived species where males invest heavily in reproduction (e.g. colonial seabirds and raptors) they obviously tend to restrict EPCs, to avoid jeopardizing the male investment (Whittingham et al, 1992;Westneat and Sargent, 1996;Petrie and Kempenaers, 1998;Sheldon and Ellegren, 1998;Briggs and Collopy, 2012;Wojczulanis-Jakubas et al, 2014). In this regard, in raptors that nest in open country the fact that extra-pair interactions are visible or audible at long distances has also been suggested as a limiting factor in EPCs (Korpimäki et al, 1996).…”