Bluebirds in winter

[Catherine Otto]

Greetings,

We had a pair of Western Bluebirds visit our suet feeder last summer quite regularly and happily we noticed one day in July they showed up with 3 youngsters! They came to the feeder throughout early to mid fall, then we did not notice them for awhile but in mid December they returned (we assume it’s the same group but how can we tell?) and now have been regular visitors at our suet feeder every day.

I wonder what these birds do in spring— will they split up and the young go their own ways? I remember that sometimes an unattached male (or juvenile from previous brood) will help at the nest but does that happen in a subsequent season- the following spring? I wonder how far these young ones might travel to find their own territories and mates as it seems beneficial that they find mates who are not siblings. Do bluebirds often form flocks of either related or unrelated individuals?

Here is a blurry photo (cell phone camera) where two of them can be seen. Often we have all 5 on the little magnolia tree together at the same time.

Catherine

[Lisa Millbank]

Young female bluebirds usually leave their family group soon after they become independent, and they go around looking for a flock to join elsewhere.  Young males usually stay in the same general area as their parents.  Because the females disperse and the males don't, in any given area, most of the males are related to one another and the females come from many different families.  An excess number of unpaired males can build up where there are many successful nest boxes.  Some of these unpaired males will join their parents in helping to raise the next year's young.  Even recently-fledged males will try to help feed their younger siblings in the very next brood, although sometimes their mother won't allow them to do this.  We have never seen a female helping, and it's said to be very rare.  Most helpers are the breeding male's sons, but sometimes one of his brothers may help.

We have often had male helpers at our box, and one year, we had two young male helpers feeding the little ones.  They also help defend the territory, and in this case they dealt with an Eastern Cottontail who was trying to dig her nest in our garden.  The bluebirds decided that the bunny was a vicious predator whose presence could not be tolerated near the nest.  The brave male and his two sons stood guard while the female incubated, dive-bombing the bunny relentlessly and chasing her across the street whenever they saw her.

Females seem to disperse several miles from where they hatched, but I'm not sure how far they will go.  The famous Bluebird Lady of Corvallis, Elsie Eltzroth, had a box at Stoneybrook Village in SW Corvallis.  One of the banded females who hatched from Elsie's box nested in our yard in NE Corvallis, and I saw one our female's sisters nesting about a mile NE of Philomath.  Currently, we have a female coming to our sunflower seed chips who has an aluminum band on one leg, and we often wonder where she came from.

In the winter, some bluebirds may leave the colder parts of their range and turn up locally, but the vast majority seem to be local birds.  I think that related males and their mates and offspring join into loose flocks and roam around widely, since they aren't tied to a nesting territory.

Lisa Millbank

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