Klemek: In large groups and small, bluebirds are on the move
During a leisurely stroll in the backyard one recent afternoon, I noticed a flock of bluebirds flying just above the treetops.
Numbering at about a dozen or so and flying in a southerly direction, the bluebirds were calling softly in their telltale bluebird warble. In fact, it was their calls that alerted me to their presence in the first place.
After bluebird broods are raised by their attentive parents, most of the offspring disperse from the immediate breeding territory. According to the literature, young bluebirds typically disperse less than a mile from their parental territories.
This “natal dispersal” is common in many species of animals. Ruffed grouse, for example, are well known for their autumn dispersals when young birds begin leaving natal areas in search of their own potential territories.
This is also the time of year when it’s common to encounter young grouse in unusual places, such as backyards or other open areas.
Young grouse, perhaps because of their inexperience and unfamiliarity with areas they’ve dispersed to, are often vulnerable to predation. And it’s no different with young bluebirds. Dispersal to areas outside their parents’ breeding territories is always new and strange to young birds. That said, dispersal is beneficial and necessary to bluebirds, including most other species of wildlife.
Moving to new areas, away from parental territories and nest-mates, reduces the chances of inbreeding. Dispersal can also provide young bluebirds their first glimpse at potential breeding territories of their own — places they might return to the following spring. Additionally, dispersal puts young birds into association with other young birds from non-related broods.
Thus, potential mates can sometimes be encountered during these natal dispersals.
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Source, image(s), credits & more: DLOnline | Blane Klemek