Field Observation 3: Social Behavior and Phenology

It was 8:00 am and sunny, about 20 degrees with little wind. Spring must be here at last, because minutes in to my walk I saw a male American Robin calling from a low bush. He was alone, and as I approached him he flew to a higher perch in a nearby tree. I could hear a Blue Jay calling from some place more distant, whether it was a territorial or a mating call I do not know. As I continued, I heard two Black-capped Chickadees singing at the same time as a European Starling and a distant Northern Cardinal.

A pair of American Crows sat in the high branches of a tree. They both called, but not in time. Then one flew away lazily and the other stayed. I walked on for a while, and found fewer birds as I went. Then I heard a Mourning Dove hooting from some thick trees, I tried to find it but would have had to trespass to succeed.

Finally, a male Northern Cardinal let me see him. He sat in some naked branches over the sidewalk, singing loudly. His brilliant red stood out against the greyish sky, and as he sang he twitched his tail a little. This red must be costly, both because it has to be sequestered and because it might make him vulnerable to predation, and lead predators to his nest. In comparison, the duller rusty breast of the American Robin seems cheaper, and is masked from above by the duller back. The Cardinal must receive enough benefit in mate selection and territorial defense to offset his costs. The Northern Cardinal’s song makes sense at this time of year, when nesting is happening and both mate acquisition and territorial defense seem likely uses of song.

I heard another Black-capped Chickadee calling from someone’s yard, and I tried pishing to attract it. Either my attempt failed or the bird was uninterested, because I got no response. I gave up and moved on. Another American Robin flew close to me and landed in the yard of a nearby house. This one seemed completely unphased by my presence. I am hopeful that this truly means the onset of Spring.

Posted on March 27, 2018 02:04 AM by tesshall