6 March- FJ3 - Field Observation: Ecological Physiology
March 1, 2020
3:30-5:00PM
East Woods Natural Area, South Burlington, VT
25 degrees Fahrenheit, partly sunny, little to no wind
Wooded area (mostly tall, coniferous trees) with a stream running through one side of the park, hilly terrain
It was a moderately cold day, so not many birds were observed. The American Crows were seen flying more than the Black-capped Chickadees that spent most of their time safely tucked in the high branches of pine trees. Not only did the trees provide a place to nest and hide from predators, particularly those too large to navigate the dense branches, but they were very high up and gave the birds a good view of everything going on below such as families walking through, dogs, and even nosy ornithology students with cameras.
The Black-capped Chickadees budgeted their time in the trees, and they did not move much. By staying still and only moving when absolutely necessary, they were able to conserve energy for heat. I did not notice them eating, and I only saw two actually fly to a different tree. It is possible they feed more in the morning, rather than in the evening when they would want to conserve heat as it gets darker and colder overnight. I did not see any birds breeding, and it was hard to tell how many were resting because these birds were less noticeable. As mentioned above, the American Crows were flying around more, calling to others and looking for food. They seemed less concerned with conserving heat and energy.
I observed a few nests that birds had been using. There were also lots of cavities in dead trees. In one dead snag, a squirrel popped its head out, but there did not appear to be any birds spending the night in this particular tree. Several of the cavities appeared to have been made by a species of woodpecker, although none were observed on this walk. These cavities provide shelter from the elements such as wind and precipitation. They also provide protection from predators. By conserving energy rather than using it to stay warm, breed, or fly, the birds are more likely to survive the winter and stay healthy.
In other seasons, conserving heat is less important especially in the summer when the weather is warmer. From April to June, it is the Black-capped Chickadee's breeding season. During this time, energy will go toward reproduction more. For the American Crows, the breeding season is earlier, and they are often incubating eggs by April. This accounts for this species being more active during this time of year.
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