“Family Aegithalidae – Very small, plain birds that move from bush to tree in straggling flocks, conversing in light, gentle notes.”  R.T. Peterson

Now that fall has wrapped its cloak of clouds around us and the winter resident birds are calling on the bird feeder, I look forward to the regular visits of the bushtits.  The Peterson guide shows us that the bushtit (Psatriparus minimus) ranges from southwest to making those in our area residents of the northern extreme of their range.  And though they are a plain, nondescript bird (aka LBJs – little brown jobs) their mention always brings a knowing smile to a birder’s conversation.

Bushtits seem to spend most of their time upside-down.  It is in this posture that they make their living gleaning the bark of trees and shrubs.  Eating mostly insects, but a few seeds and fruit also, bushtits move in frenetic waves through the branches.  Observing the intensity of their foraging, I have to think that any tree receiving a bushtit gleaning says “thank you” to the chattering flock as it sweeps through its’ limbs. 

All birds need to continually stoke their metabolic engines but the microscopic bushtit is at a physiological disadvantage compared to larger birds.  This is because the surface area to volume ratio of small animals is much greater than that of large.  Since surface area is the “door” through which heat escapes an animal, small animals, by their size, lose more heat than larger animals and therefore must have a higher metabolic rate to maintain the same body temperature.  Compound this size disadvantage with shorter daylight hours and colder night temperatures and the bushtit must use every daylight moment feeding to keep the metabolic engine running.  At night, bushtits are known to conserve energy by roosting in huddles, literally a ball of feathers with their tails pointing out.

An examination of the bushtit body reaffirms what we already know from observing them and birds in general.  When you compare a buteo to an accipiter you notice that the buteo, a soaring hawk, has long, broad wings and a relatively short tail while the accipiter possesses the stubby wings and long tail for careening through the trees.  So too for the bushtit.  The elegantly long tail is not for looks, it is a rudder for steering through the tight spaces within a tree.

As I sit at the window watching the feeder, many species visit and roost in the trees but the bushtits sweep through the yard.  It appears as though chickadees target the feeder.  They make repeated foraging runs from nearby trees to the feeder and back.  But the bushtits do it differently.  They don’t work the feeder, it just gets in the way!  As the flock moves from shrub to tree around the house they encounter the feeder in the course of their gleaning.  And rather than taking an extended pit stop to gorge themselves on suet and seed like chickadees and house finches, they each take their turn.  One by one they “glean” the feeder politely taking their turn and moving on as if to leave some for the others.

As you struggle to count a mixed flock of chickadees, kinglets, and bushtits 50 feet up a Douglas fir during the Christmas Bird Count remind yourself of the nature of bushtits.  Rather than muttering to yourself about your problems, remember the politeness and industry of bushtits and let the smile come to your face – then guess.

(Article written & provided by J. Baker)

 

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