WEDNESDAY, June 13 (HealthDay News) -- If you're a male Nazca booby, being a good husband and father may not be enough to convince your mate to stand by you, says a Wake Forest University study.

It found that female Nazca boobys -- long-lived seabirds that live in the Galapagos Islands -- often switch mates after a few seasons of successfully raising chicks. This may be because the male starts to look a bit ragged from the demands of parenthood, so the female dumps him for a fresher-looking male, explained study co-author and doctoral student Terri Maness.

Since there are significantly more males than females in the colony Maness studied, it's also easy for a female to find a new mate.

"Our study population has 50 percent more males than females, creating the opportunity for females to trade a current mate, which may be worn out from recent breeding effort, for a 'refreshed' non-breeding male," Maness said in a prepared statement.

For this study, she analyzed 14 years of data on 950 males and 700 males. During that time, most of the females ditched old mates for new ones.

"This study really predicts that the probability of divorce increases with the birds' success at breeding and raising a chick, because the effort required may tire out the male and, consequently, his mate may reject him," Maness said.

But there is good news for a spurned male. After he's recovered from the rigors of parenthood and looks presentable again, he may be selected by another female.

The study appears in the June 13 issue of the Proceedings of the Royal Society B: Biological Sciences.

More information

The American Association for Marriage and Family Therapy offers advice on how to prepare for marriage.

-- Robert Preidt

SOURCE: Wake Forest University news release, June 13, 2007

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