(Burrowing Owl Update Below)
November is way too early for a Song Sparrow to think about mating and breeding, but the bird just can’t help singing, so it sings any time of year. This one hopped on top of a Coyote Bush on the north side just steps from the paved path, and didn’t mind in the least that I set up my camera gear in plain view and earshot. When a runner came by, the bird hopped off the top twig, but a few seconds later came back and resumed the recital.
The Song Sparrow repertoire has been studied for years, and researchers have done all kinds of clever experiments with tape recorders, speakers, and captive birds reared in soundproof chambers listening to the songs of canaries and other birds to see if they would learn them. All this research has kept track of human-audible sound bites like upwhistles, downwhistles, trills, and the like, extensions of concepts from human music and language.
New research shows, however, that birds aren’t all that interested in those sound bites. What they really listen to is fine acoustic details in the sounds that go by too fast for human ears to pick up. A research report by Adam Fishbein of UC San Diego in Scientific American this past May is based on using recording equipment capable of resolving variations in birdsong at the millisecond level. His group, and others working on the issue, found that song patterns that to our ears sound repetitive contain rich and varying data about gender, age, location, food availability, and other items in their auditory microstructure. Birds’ ears, probably because they have a smaller cochlea, are capable of picking up these modulations. A songbird’s voice box, the syrinx, is capable of creating millisecond modulations. The muscles in the syrinx contract and relax faster than any other vertebrate muscle, although those of bats used in echolocation may be even faster.
Much research is still being done, and many questions remain unanswered. But it’s clear already that birds listen to birdsong differently than we do, and differently than we imagined they do.
Burrowing Owl Update
My urge to go out in the rain and see how the owl is doing, as I’ve done several times in the past, fizzled this morning and I stayed home, warm and dry. When the rain stopped in early afternoon, I was there, and was not disappointed. The Burrowing Owl was not only present in Perch B, it stood taller than ever before, so that I was able to get a full frontal image including a leg. As I’ve documented in the past, these owls love the rain and expose themselves to it as much as possible. (See e.g. “Owls in Rain” Nov 9 2021.) Within limits. Why that is I can’t say, but it may have to do with a sense that their enemies are less active in the rain so that it’s safer to stand out.