Through my binoculars, I watch two male Eastern bluebirds (Sialia sialis) in the heat of the summer breeding season.
While out catching insects for his breakfast, the first male suddenly spies a house wren investigating his nest. No doubt she is eyeing her chances of stealing the box, puncturing his eggs and building her own nest on top. Exploding in a fury from the bushes, he careens towards the intruder, wrenching her backwards off the ledge with a violent bite and chasing her off into the scrub. Once she has given up for good, he returns and settles on top of the box. He puffs out his breast and preens his brilliant blue wings. His nest is safe another day.
The second sits alone on a telephone wire. Silhouetted against the grey morning skies, he looks dull and disheveled. He gazes at his box in silence, his mate nowhere to be found. Yesterday, he brought plump caterpillars to his four noisy nestlings. Today, the nest has a stale smell. The straws that his mate wove so carefully into a perfect cup are in disarray, and their babies are gone.
Across the summer I find cold, flea-bitten nestlings shoved against the wall under a teetering pile of new sticks as often as I find soft blue eggs or parents carrying insects back to their hungry children. For every successful fledging there are two failed attempts. Another bird can tear out every last blade of grass and replace the nest with their own in a matter of minutes. A snake can slither up the pole and devour a mother and her healthy brood of hatchlings overnight.
In my lab notebook, bluebirds fly, perch, sing, forage and preen. Simple descriptive actions. My notes record two after-second-year male S. sialis, one a failure, the other a success. As a student of evolutionary biology, I have been trained that the events of an individual life matter little. One nest, even one pair’s nesting season, is inconsequential compared to the total reproductive output of a population.
Yet when I look up from my page, I see two fathers struggling desperately for their family’s survival. I empathize from afar as they celebrate their victories and grieve their losses. It is more than mere instinct to care.
Sarah Jean McPeek