Do any local breeding birds mate for life?
Why? [Leo, San Francisco] A: Some local birds do form long-lasting pair bonds of several different kinds. Ravens and scrub jay pairs hang out together all year, not just at breeding time. Wrentits and resident Canada geese also have long relationships that can last more than ten years. Most songbirds have the same mate every spring, but this has more to do with site fidelity than with long-term partnership. Males usually arrive early and use songs and displays to define, control, and defend the same territory each year. If a female arrives and finds the same male, courtship ensues, copulation follows, and both tend to the young. But if last year’s male lost his territory, then the new guy will do just fine. So real estate is more important than individuals. But there is a direct correlation between fitness and the ability to secure good territory. Most of the 12 seabird species that breed in our region mate for life. But it’s fidelity to territory, not to individuals. Scientists are di
