Today, I’m making a long overdue correction of a terrible oversight, writing about a bird I’ve somehow never covered before. This is a wonderful species, plain and common —among my favorite traits, as you might know if you’ve read my titmice and towhee columns. But this bird is also among our most impressive architects, charmingly social and quite arguably unmatched in pure adorability. I’m talking about bushtits.
Many people are more familiar with our oak titmice, common backyard feeder birds that are likewise small and plain gray. This superficial similarity initially earned bushtits a similar name, but we have since realized that they belong to an entirely different family. (Etymologically, “tit” refers to something small and so in some sense remains quite appropriate.)
Bushtits lack the titmouse’s crest, are small insect specialists rather than nut-cracking generalists, build quite different nests than titmice and lead markedly different social lives. There really are no other birds like them on the continent.
Let me start with the immediate reaction of many first-time bushtit viewers: these birds are extremely cute. One of the primary ingredients in this cuteness in our eyes is also an important feature in their natural history: they are tiny. A bushtit weights about .2 ounces, equivalent to about half a chickadee. If you put four jumbo paperclips on one side of the scale and a bushtit on the other, the paperclips would be anchored to the ground while the bushtit bounced fruitlessly up and down like a little kid outweighed by a big one on a see-saw. Combine this tininess with their overall proportions, which can best be imagined by envisioning fluffy gray ping-pong balls with tails, and you already will have a strong sense of the bushtit’s immediate adorability.
After pure physical cuteness, the bushtit’s next most distinctive trait is intense sociability. The bushtit way of life is to travel around in flocks of some 10 to 50 birds, all constantly in motion as they search for aphids, scale insects, small caterpillars and other tiny invertebrates. (The niche for which tininess optimizes you is branch tip foraging and clinging to the underside of leaves, where even titmice and chickadees seem like clumsy, heavy beings.)
While essentially small-beaked eaters of the suitably miniscule, bushtits will occasionally visit feeders for suet or shelled sunflower seeds.
A flock of scurrying cotton balls in constant spluttering motion is an endearing sight. But it gets better! At the end of the day — about the only time they ever cease to be in motion — bushtits will also sleep in the same roosting site, sharing some protected branch. And on cold nights, they will inch together until they are one continuous huddle. In other words, as tiny creatures, bushtits have a high surface area to volume ratio and are therefore more vulnerable to cold temperatures. But as social birds, they have a solution: snuggling. I’ve occasionally seen this even during warm California daylight with recent fledglings that apparently have a particularly strong instinct towards huddling and can default to this behavior in their early days.
The only time when bushtits depart from their highly social existence is during the nesting season, when for a few months of spring you might come across that rare sight of two — and only two — bushtits. This diminution of numbers causes no diminution of interest, however, because springtime is when the bushtits perform their greatest feat: nest construction.
And there are few nests to match these. Bushtits stitch long hanging socks, some 12 inches in length, that earn them their Spanish name of sastrecillo, or little tailor. The main materials are usually grasses and lichens, often with dashes of flowers, small twigs and spider silk, and lined with soft fur or small feathers.
This sock conceals and protects the eggs from most avian predators. It protects them from cold — bushtits incubate their eggs for fewer hours per day than most cup-nesting songbirds. It protects them from heat — the interior of a bushtit nest has been measured as 15 degrees cooler than the exterior in hot weather. And in this nest, six 1/2-inch eggs will nestle with their white-eyed mother and with their dark-eyed father.
Together all will snuggle as they labor to perpetuate soft smallness in the world.
Jack Gedney’s On the Wing runs every other Monday. He is a co-owner of Wild Birds Unlimited in Novato and author of “The Private Lives of Public Birds.” You can reach him at jack@natureinnovato.com.
