Sunday, October 24, 2010
'Holy crow!' seems apropos
Tonight’s PBS “Nature” program tells us all about crows. What we may have thought of only as cawing, mischievous birds we now know to be the smartest birds.
Not only do crows recognize human facial differences, but they also warn one another of humans who are dangerous to them. And they have different warning calls for cats and hawks. All such alerts are done in the hoarse tones associated with crows, although they also have soft, melodious ways of speaking to family members.
Like humans and great apes, New Caledonian crows use tools. Not only that, they make tools. Not only that, they use tools to make tools.
It’s thought that their being omnivorous eaters encourages crows’ brain development. One example: they drop walnuts from just the right height to crack, but not shatter, on a road; then they retrieve the nuts while the light’s red. Young crows also can spend up to five years with their parents – another means of cognitive development.
Though crows can learn who’s good and bad for them, the question is, do parents pass on this knowledge to their young? This is something only a very small group of animals can do.
One year-long experiment, involving tracking of radio-rigged and leg-banded crow fledglings, indicates the answer may be “yes.” They can learn, remember and put to use info they got from their parents – for example, the reaction to humans wearing a certain mask associated with threats to crows.
This TV program raised serious questions: do crows need such research findings? Does it do them any good to perform tests for scientists? Why can’t crows – and all other wild animals – simply be left alone to live their lives the best way they can? (This foreshadows a discussion of Lee Hall’s 2nd book, “On Their Own Terms,” which promotes “Let them be!” as the only right approach to wild animals.)