Researchers tie crest size to seabirds' suitability as a mate

April 16, 2009
These courting auklets stand on a rock on St. Lawrence Island in June 2007. The male auklet is on the left. Credit: UAF photo by Hector Douglas

A newly released study by researchers at the University of Alaska Fairbanks offers evidence that in one breed of northern seabird, the size of males' feather crests may be more than simple ornamentation.

Their study, published this month in of the Journal of Comparative Physiology B, shows that size may be a physical indicator of a male crested auklet's quality as a mate.

Scientists have long noted that female auklets prefer males with larger crests. But until recently, they did not know why. Low levels of hormones in males with larger crests indicate that they cope better with the stresses of reproduction, such as finding food, competing with thousands of other birds for mates and nest sites, and helping rear chicks.

"Females will divorce shorter-crested mates for the opportunity to mate with longer-crested males. Our study suggests that longer-crested males could contribute more to because they have greater capacity to meet the social and physiological costs," said Hector Douglas, assistant professor of biology at the Kuskokwim Campus in Bethel.

Douglas and collaborator Alexander Kitaysky, an associate professor at the UAF Institute of Arctic Biology, say their results fit into a larger theory about animal societies.

"There appears to be a social hierarchy at the colony which is correlated with the size of the male ornament and this, in turn, is related to the levels of stress hormones," Douglas said. "The cost of attaining and maintaining dominant status is reflected in the animals' physiology and this has a distinct pattern in the society."

Douglas and his field team studied the small, sooty-gray seabirds during fieldwork on Big Koniuji in the Shumagin Islands in the Aleutian Chain during June and July of 2002. They captured and measured the auklets at a mountainside colony and collected blood samples. Kitaysky's lab analyzed the blood samples for the stress hormone corticosterone. They found that larger crests correlated with lower levels of corticosterone in the males' bloodstream.

"Theoretically males that have a lower level of baseline stress hormone have a greater capacity to respond to additional stress," Douglas said. "The with the larger crests had markedly lower levels of corticosterone and therefore they should be better mates. We suspect that crest size is an outward indicator of intrinsic quality, and the data on hormones appears to confirm this."

Source: University of Alaska Fairbanks (news : web)

Explore further: Mating with showy males may reduce offspring’s ability to fight off pathogens

Related Stories

Researcher finds amorous avian anointment protects mates

August 21, 2007

Hitting it off with members of the opposite sex takes chemistry. University of Alaska Fairbanks researcher Hector Douglas has found that, for crested auklets, chemistry has both amorous and practical applications.

The best both of worlds -- how to have sex and survive

September 20, 2007

Researchers have discovered that even the gruesome and brutal lifestyle of the Evarcha culicivora, a blood gorging jumping spider indigenous to East Africa, can’t help but be tempted by that ‘big is beautiful’ mantra ...

Females decide whether ambitious males float or flounder

January 30, 2008

Aggression, testosterone and nepotism don’t necessarily help one climb the social ladder, but the support of a good female can, according to new research on the social habits of an unusual African species of fish.

Recommended for you

Mapping the protein universe

October 9, 2015

To understand how life works, figure out the proteins first. DNA is the architect of life, but proteins are the workhorses. After proteins are built using DNA blueprints, they are constantly at work breaking down and building ...

Gene editing: Research spurs debate over promise vs. ethics

October 9, 2015

The hottest tool in biology has scientists using words like revolutionary as they describe the long-term potential: wiping out certain mosquitoes that carry malaria, treating genetic diseases like sickle-cell, preventing ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.