During the past few weeks, I have received reports that eastern bluebirds have already begun nesting in many locales throughout Georgia. Being able to watch a pair raise their young in our yards is always one of the most enjoyable wild dramas played out in our backyards.
When we see a pair nesting one or two more times, it is only natural to assume we are watching the same two birds that we saw earlier in the spring. This belief is so popular, most bluebird landlords rarely wonder if this is indeed the case. This assumption has, however, been tested in a number of studies. You might be surprised at what these research projects found.
For example, in one study, biologists learned that most bluebird pairs remained together, if their first nesting attempt proved to be successful. However, when it fails, only 30-50% of the pairs remain together for another attempt to nest in the same nesting season. In an apparent effort in be successful during a re-nesting effort, the adults will breed with another mate.