Prenuptial perfume: Alloanointing in the social rituals of the crested auklet (<Emphasis Type="Italic">Aethia cristatella</Emphasis>) and the transfer of arthropod deterrents

Alloanointing, the transfer of chemicals between conspecifics, is known among mammals, but hitherto, the behavior has not been documented for birds. The crested auklet (Aethia cristatella), a colonial seabird of Alaskan and Siberian waters, alloanoints during courtship with fragrant aldehydes that are released from specialized wick-like feathers located in the interscapular region. Crested auklets solicit anointment at the colony, and prospective mates rub bill, breast, head, and neck over wick feathers of their partners. This distributes aldehydes over the head, neck, and face where the birds cannot self-preen. The resulting chemical concentrations are sufficient to deter ectoparasites. Auklets that emit more odorant can transfer more defensive chemicals to mates and are thus more sexually attractive. Behavioral studies showed that crested auklets are attracted to their scent. Wild birds searched for dispensers that emitted their scent and rubbed their bills on the dispensers and engaged in vigorous anointment behaviors. In captive experiments, naïve crested auklets responded more strongly to synthetic auklet scent than controls, and the greatest behavioral response occurred during early courtship. This study extends scientific knowledge regarding functions of alloanointing. Alloanointing had previously been attributed to scent marking and individual recognition in vertebrates. Alloanointing is described here in the context of an adaptive social cue — the transfer of arthropod deterrents between prospective mates.     

Socioeconomic development and ecological traits as predictors of human–bird conflicts

Because of the significant impacts on both human interests and bird conservation, it is imperative to identify patterns and anticipate drivers of human–bird conflicts (HBCs) worldwide. Through a global systematic review, following the PRISMA 2020 guidelines, we analyzed the socioeconomic factors and bird ecological traits driving the degree of knowledge and extent of HBCs. We included 166 articles published from 1971 to 2020 in our analyses through which we built a profile of the socioeconomic conditions of 52 countries with reported conflicts and the ecological traits of the 161 bird species involved in HBCs. Although HBC expanded worldwide, it had the greatest impact in less-developed countries (estimate 0. 66 [SE 0.13], p< 0.05), where agriculture is critical for rural livelihoods. Species with a relatively greater conflict extent had a relatively broader diet (estimate 0.80 [SE 0.22], p<0.05) and an increasing population trend (estimate 0.58 [SE 0.15], p<0.05) and affected human interests, such as agriculture and livestock raising. In countries with greater biodiversity, HBCs caused greater socioeconomic impacts than in more developed countries. Our results highlight the importance of understanding and addressing HBCs from multiple perspectives (ecological, sociocultural, and political) to effectively protect both biodiversity and local livelihoods.