Alcids by Audubon from here. Crested Auklet is lower right.

While Secret Sex Lives estivates we’ll try to pick up some of the slack.  Science Daily has a story on Crested Auklets (Aethia cristatella) that gives new meaning to the old pickup line “Hey baby is that aldehydes I smell or are you just happy to see me?”

Breeding pairs of these small seabirds smear a citrus-smelling secretion on each other as a part of their nuptial rites.  Researchers have found that the compound contains chemicals with anti-parasite properties.  According to Sibley’s Bird Life & Behavior the compound is so pungent that it can be smelled by birders on a boat some distance from the breeding colony.

Like many pelagic birds, alcids have elaborate mating behaviors, no doubt because breeding is a crowded affair with thousands of individuals converging on a few limited breeding sites.  In such conditions it’s paramount to winnow the hunks from chaff relatively quickly.  And, since any offspring are bound to have a rough life ahead out on the open ocean, getting some good genes for your babies is key.

Interestingly the elaborate sexual signals of alcids (e.g. the eponymous crest in A. cristatella, or the clownish beaks of their more familiar cousins the puffins) are seen in both sexes, in contrast to dimorphic sexual displays in many other species. I recently saw a talk by Kevin Padian discounting sexual selection as a good explanation for elaborate dinosaur structures since there is little evidence of sexual dimorphism in these creatures.  The crests and tufts and whiskers and bills of Alcids, and their citrusey love juices, would seem non-dimorphic sexual selection in action.

[Note that the Audubon painting appears to show some dimorphism in the two individuals at left, IDed as male and female ‘Ancient Murrelets’ (Synthlibrorampus antiquus) but I’m pretty sure the brown one is a different species, maybe a Marbled Murrelet (Bracyramphus marmoratus).]