Ever wished for a more palpable measure of a date’s long-term potential? Some visible sign telling you whether he will leave the toilet seat up? Gouldian finches can’t commiserate: females can judge a male just by looking at his head.
A new study in the journal Science has found that females produce more healthy offspring when they mate with males of similar coloring to their own, and that as a result, females demonstrate pronounced sex bias towards compatibly feathered studs.
In a strange twist, moreover, female finches have the ability to control the sex of their offspring, and when the female finche mates with a male of a different head colour, they tend to produce more male offspring. According to Sarah Prkye, lead scientist on this study, males are preferred in this circumstance because male birds are more likely to survive incompatible parents than are females. The mechanism of this control is not known.
“It is pretty amazing,” says the unfortunately named director of this sex study, “to think that the female herself has so much control – subconsciously of course – over this basic physiology.” The author of BV submits that Dr. Pryke is perhaps a tad naive: these birds are not acting on subconscious instinct: they are simply living by the motto that if brother didn’t have good ‘n’ plenty of his own, in love [they] never [will] fall.
This conclusion is borne out by Pryke’s own admission that
“Females really don’t want to mate with a male with a different head colour” but because “there simply aren’t enough compatible males,” the unmatched females eventually “use this control to make the best of a bad situation.”
We feel ya, sisters.