Colonial seabird's paralytic perfume slows lice down: an opportunity for parasite-mediated selection?

Selection for chemical signals in birds could be influenced by parasitism as has been previously suggested for visual and acoustic displays. Crested auklets (Aethia cristatella), colonial seabirds from Alaska and Siberia, offer an example of how this might occur. Crested auklets secrete lipids in plumage, possibly as an indicator of status and attractiveness.

Size of ornament is negatively correlated with baseline corticosterone in males of a socially monogamous colonial seabird.

The Goymann-Wingfield model predicts that glucocorticoid levels in social animals reflect the costs of acquiring and maintaining social status. The crested auklet is one of the few avian colonial species where a mutual ornament in males and females is used in both sexual and aggressive displays. Previous studies of the crested auklet support the notion that the crest ornament is a badge of status in this species.

Seasonal covariation in progesterone and odorant emissions among breeding crested auklets (Aethia cristatella).

Crested auklets emit a citrus-like odorant that is seasonally modulated, suggesting that it is a secondary sexual trait. We hypothesized that expression of the chemical odorant is facilitated by steroid hormones, similar other secondary sexual traits in birds. Therefore we examined variation in concentrations of hormones in blood plasma and odor production during incubation and early chick rearing.

Prenuptial perfume: alloanointing in the social rituals of the crested auklet (Aethia cristatella) 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.

Measurement of chemical emissions in crested auklets (Aethia cristatella).

This report presents the first quantitative estimates of emission rates for chemical signals in a bird-the crested auklet (Aethia cristatella). Volatile emissions from live birds were captured in a purified airstream onto polymer traps. Traps were eluted with methanol and analyzed with gas chromatography-mass spectrometry.

Interspecific differences in Aethia spp. auklet odorants and evidence for chemical defense against ectoparasites.

The true auklets (Genus Aethia) are small planktivorous seabirds of the Bering Sea and North Pacific. Two species, the crested and whiskered auklets produce volatile citrus-like odorants. We here show that the whiskered auklet odorant is composed predominantly of two odd-numbered aldehydes (heptanal and nonanal) with no detectable unsaturated aldehydes.