by Erik Baard
If you want to score with New Jersey babes, wear red. At least if you’re a barn swallow. And on second thought, I’d advise swallows to do two things: avoid dressing for a role they’re not able to fulfill, and watch Star Trek.
One rare trait in the animal kingdom is self-recognition in a mirror. You probably didn’t grasp that the reflected figure was yourself until you were about 18 months old. Other primates and species as diverse as elephants, dolphins, whales, and magpies also shared the insight, some without special training.
Individuals of most species therefore rely entirely on community feedback for their sense of status, or in squishier terminology, “self-esteem.” A Current Biology report on an experiment with barn swallows (which we reported in our May 27 posting were darting around Fresh Kills) provides an excellent demonstration of this fact. Dig deeper with the full press release and video.
A study of 63 male barn swallows, captured from six colonies in New Jersey at the start of breeding season. All had blood samples drawn, to measure hormonal levels. Half of them were gussied up with a $5.99 nontoxic red marker to make their breast plumage match the richest shade of the population. The birds were then released and recaptured a week later. The enhanced males showed a spike in their testosterone levels at a time in their annual cycle when they should be slacking off.
A few swipes with a magic marker set off a fascinating loop of physical and neurological interplay, reminding us that the psyche is very somatic and that the sense of self is fluidly social.
The deeper hues attracted and retained more females, who read it as a sign of robustness, and that attention pumped up the bird’s biochemistry in line with his sense of social standing.
Some reports, and the researchers themselves, chuckled that the study proves “the clothes make the man.” I hold strong reservations against that emphasis.
An increased capacity for dominance through higher testosterone levels is vital to perpetuating the pigmentation’s potential genetic windfall, because envious rivals will spar with a male who has more mating opportunities. In a sense, one can view the testosterone boost as the endocrine system’s frantic game of catch-up as the altered males try to grow into roles for which they aren’t equipped.
One possible sign that the ink job was a mixed blessing at best, that there’s a steep cost to primacy, is that the enhanced males lost weight. Is that because they spent so much time getting busy with the females, or was the competition from males taking its toll? Predators can also target a brightly feathered barn swallow more easily, perhaps leading to a few stressful encounters and energetic evasions. In nature, showy displays like plumage and antlers are outgrowths of a stronger and capable organism – truth in advertising, as University of Colorado at Boulder biologist Rebecca Safran, the lead author of the study, noted.
I wonder if a longer-term study would reveal greater mortality rates for the posers than the authentic alpha males. Also, now this is stretching the study much further out, I can imagine that isolating members of the species and leveling the pigmentation playing field in the same manner would in time cause sexual selection for females with greater visual acuity, to detect the chromatic fakes, or the evolution of new male signals of prowess.
Even among the Wodaabe people, where young men wear elaborate makeup and outfits (pictured below) to parade before marriageable women, special emphasis is made on height, white teeth, and perfection in the whites of the men’s eyes (to the point where they roll their eyes back to show off the purity). In short, catch their attention with the flashiness, but close the deal by proving your health.
Of course, we could have all saved ourselves a lot of time by heeding the central wisdom of Star Trek: any situation is made worse by a red shirt.