AsianScientist (Jul. 26, 2016) – Female purple-crowned fairy-wrens are in such fierce competition over territory that they are willing to ‘divorce’ their male partners for a better patch, according to a study from Monash University.
The study, published in Behavioral Ecology, shows how important intact high quality habitat is for these birds, and to what lengths they will go to secure a top spot.
From studying 317 breeding pairs to learn what was driving the behavior, the researchers found that as many as one in five avian pairs ended in divorce over nine years. Lead researcher Associate Professor Anne Peters said they were surprised to find it was the females who were more likely to break up.
“Females exhibit long term planning and are more likely to end their relationship when the opportunity for a better territory arises,” Peters said.
“We found females were prepared to wait, sometimes up to three years, for a good vacant spot to come up—where the female owner has died or moved on.”
Found in Western Australia’s Kimberley region, it’s estimated less than 10,000 purple-crowned fairy-wrens remain in the area. Unlike birds that move away from their territory and separate after breeding, the fairy-wrens live together in pairs, all year round, in the same patch.
“These females are sitting there, they’re not happy with their partner or their territory; they have an affair on the side and they’re more likely to divorce. With divorce, they get a different partner and a different territory. The territory seems to be more important than the partner,” Peters said.
PhD candidate Ms. Nataly Hidalgo Aranzamendi, who is the first author of the study, said that the females were prepared to take drastic action to gain a better territory.
“We found that older females sometimes kicked younger females out of their territories to claim these as their own,” Aranzamendi noted.
The researchers believe that divorce presented a significant advantage for females to improve reproductive success in the long term, and the immediate benefit is a better territory.
“This endangered bird lives in a harsh, unpredictable environment where 80 percent of nest attempts end in failure, so females are prepared to divorce for a better territory because a good site for nesting will pay off,” Aranzamendi said.
Source: Monash University; Photo: Michelle Hall.
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