Why pretend to be male Marsh Harrier females

November 9, 2011 14:25

To avoid collisions with potential rivals, some male Marsh Harrier "dress" in females.

Males and females of Marsh Harrier differ in appearance: males gray plumage and yellow eyes, female mainly brown with white shoulders and head and brown eyes. In addition, a third more females than males. It would seem surprising: in many species, the males and females differ from each other. But there is a rare marsh harriers in birds phenomenon: some males literally change into a female — and they remain in such an outfit for life.

Around the second year 40% of the males grow their Harrier currently brown feathers, and, despite the yellow Samtsova eyes, confusing them with female worthless. Usually such "zakosit" practiced by female fish, reptiles and insects. In birds, this happens to young males: the similarity with the female helps them evade attacks strong and aggressive adult opponents. But, as adults, these males regain normal "masculine" attire. Only at Spoon-Ruff male transvestite female plumage retain for life, scientists believe that this outfit allows males during the breeding season sneaking up to females.

As to the Marsh Harrier, here males, apparently, life pretending females to avoid fights with neighbors. Several biologists from France and Spain set up an experiment, apart dummy bird nests near 36 pairs of harriers. Fake imitated or female, either a conventional male, or a male pretending to be female. Male Marsh Harrier typical territorial behavior, and the birds were quick to attack the dummy-l'oeil — but only those that were similar to them, the "normal" males. In relation to the casts of male and female cross-dressing aggression was much lower.

The "dressed" males were less aggressive and did not attack the dummy, simulating male "real." We can say that they have entered into cunning with other males nonaggression pact. But "effeminate" birds were actively involved in the collective pursuit of the predator, which does not happen with normal males and females attacked dummies and "dressed" males, although this is rarely done. Latest looks strange when you consider that every female to male — is a potential sexual partner. In an article published in the journal Biology Letters, the authors state that these males can copy the behavior of females during the breeding season which sometimes perceived as an enemy of another female.

At first glance, the winner is exactly this (not prone to "dressing up") male. If it gets near the nest or nests surrounded by transvestites, then he will not have to take part in the clashes, and collective action effeminate birds and protect his home from intruders and other predators. But obviously, and "dressed" males should also have an advantage from his attire. In the near future zoologists want to find out whether the unexpected behavior of male transvestites result of rearrangements in the hormonal system — or they learn to behave differently in females and fellow camouflage.

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