Birds communicate with scent during courtship

A researcher at the University of Alaska Fairbanks has discovered that chemistry plays both amorous and practical applications when crested auklets mate.

Washington, Aug. 22 : A researcher at the University of Alaska Fairbanks has discovered that chemistry plays both amorous and practical applications when crested auklets mate.

Hector Douglas says that during courtship, a behaviour called alloanointing, birds rub a citrus-like scent secreted in wick-like feathers on their backs on each other.

Some mammals, such as peccaries, are known to show such behaviour, although it was not documented among birds so far.

"During courtship the male solicits the female by adopting a horizontal posture and giving a soft choking call. She rubs her bill and upper body over his wick feathers. Then she offers her wick feathers to the male, and they reciprocate several times, smearing the chemicals over their heads, necks and upper bodies," explained Douglas, an assistant professor of biology at UAF's Kuskokwim Campus.

A paper published in the German journal Naturwissenschaften describes crested auklets as small black and gray seabirds that nest in huge colonies on remote island cliffs in Alaska and Siberia. They have bright orange bills, white facial plumes, and a showy feather crest protruding from their foreheads.

Douglas observed the unique mating ritual while conducting experiments with lifelike models of crested auklets on St. Lawrence Island, a remote outpost in the northern Bering Sea just 38 miles from Siberia. He concealed chemical dispensers in blocks of construction foam that he painted to resemble rocks, and then placed the decoys and models on the blocks.

"The crested auklets searched for the scent with their heads down in a conspicuous sniffing behaviour. They honed in on the scent, rotating their heads to place their nostrils directly over the dispenser. Then they rubbed their bills over the dispensers just as they would on the wick feathers of their partner. Next, the birds rubbed themselves on the lifelike models right in the area where the wick feathers are located," he said.

He used a similar experiment with captive crested auklets at the Cincinnati Zoo to learn if the behavioural response is tuned to breeding.

"In two successive years the strongest response to the scent occurred during early courtship. These combined studies support the idea that the birds communicate with the scent during courtship," he said.

Douglas says that his study also indicates that this mating ritual may help protect the birds from parasites, such as ticks.

"What you smell is what you get in terms of protection against ticks. The scent contains aldehydes, which repel ticks," he said.

He further said that some auklets emit more of the scent than others, and that the birds gain an advantage by anointing with mates that have more of the tick-repelling scent.

"When crested auklets anoint their mates, they spread these chemical defences over these hard-to-reach places, helping protect them against ticks," he said.

ANI