Sunday, February 5, 2012

I'm sitting by the back door just watching the flurry of activities. I am amazed by the diversity of little birds! Okay, not so much the actual number of species I can count (five), but as I watch a squirrel carefully but quickly gather sticks and leaves and hustle them up to his nest in the maple tree, I am amazed. How do squirrels know how to make their nests? How do they know that a swallow-style nest or a rabit-style burrow doesn't suit them? For that matter, how do birds know how to place grasses and twigs to form a cozy home?

Humans have learned to build and repair structures over thousands of years of trial and error, so why am I surprised that animals can build homes? Because: every single one of them can! Consider again the human: only a few are builders, but every bird and squirrel is a builder (at least in my yard). I have read that the cuckoo bird leaves its eggs in a stranger's nest, to be hatched and raised by surrogate parents. How does the cuckoo chick know to carry on this peculiar habit? Who teaches this behavior to the bird? Does it find older cuckoos in the wild that orally pass on the traditions of their kind? I digress....

In some human cultures, it is customary for the whole village to help build a home for a newly wedded couple. Can you imagine if sparrows or cardinals flocked to build nests for the newly mated yearlings? No! Each adult bird is capable of selecting a suitable site and building a nest for himself! I am oversimplifying things, of course. Birds are generally regarded as having identical properties within a species, such as the common house sparrow (Passer domesticus). They each can identify safe food sources, have very similar eyesight and hearing (do they?), and can all fly with equal ability (altitude, velocity, distance, etc). Or do they?

Humans show much variation in skills: some are eloquent speakers or writers, while others are clumsy with words. Some humans have developed fine motor skills and can perform the most delicate tasks with ease, while others are "all thumbs." Some can run faster, jump higher, or lift heavier objects than others of the same age. Homo sapiens shows much diversity in height, weight, fat distribution, lean muscle mass, foot length, hand size, finger length... Do birds also show this variation? Can some Northern Cardinals fly higher than others? Do they train themselves to be able to do so? Do birds brag about the cat they chased away last week or how they barely missed being struck by a vehicle? Do they share information about a new food source, or does each bird have to find it for himself?

I am just amazed at Earth's biodiversity and how it all works together, when we let it. Humans seem to be the anomaly... we do more to disrupt and destroy the natural balance of the Earth than we do to restore it... but, again, I digress.... Watching the cardinals, doves, finches, jays and sparrows flock around the feeder together with two squirrels busily rummaging around for nest materials... I just smile with wonderment!