Male Harris sparrows are pugnacious beasts. They signal their status by the darkness of their plumage, and woe-betide any male whose signal is false—for if an itinerant ethologist blackens a subordinate’s feathers, the dominant birds recognise it as a fraud and beat it up. Normally, though, behaviour and outward appearance are in alignment, having been arranged that way by evolution, and subordinate birds do not push their luck. For female Harris sparrows, however, plumage does not matter in this way. And a paper just published in Psychological Science, by Michael Petersen of the University of Aarhus in Denmark and Daniel Sznycer of the University of California, Santa Barbara, suggests that in both respects people are similar to these birds.
Read the whole story: The Economist