Will's Field Journal #4

On Sunday, March 21st, I visited Wheeler Nature Park in South Burlington, VT. From the parking lot, I walked down through the open field area and into cedar dominated forest. At this point I decided to turn right and walk up the hill through more cedars. Then I followed the trail as it looped around and took me back down into the lower cedar forest and eventually into the more open, beech and maple dominant forest. I followed the trail out of this forest patch and into the lower part of the open field area until I reached a small bridge over a stream, at which point I sat for about ten minutes. Then I followed the trail back through the forest yonder from whence I came, and lo and behold I ended up back at the parking lot. I started the walk at 3:29 pm and ended it at 5:53 pm. It was a beautifully clear and sunny afternoon, 63˚ F, very little wind.

Wheeler Park was rich with bird song, and I had plenty of opportunities to observe how birds use their calls and songs to interact in different ways. One particularly interesting interaction was between a pair of chickadees I saw that seemed to be gathering nest materials. They were fairly close to each other, and even though they were hard at work stripping bits of moss and twigs from the cedars they were in, they still called to each other regularly, and occasionally calls from one bird would draw the other bird closer. Another call/song related observation I made was that towards the end of my walk, as the sunlight light grew dimmer, I heard more birdsong. I imagine this has to do with the circadian rhythm of birds, and the fact that their behavior over the course of the day is linked with this rhythm, and largely triggered by their perception of light through their pineal gland. The change in light seems to trigger a behavioral change in this case.

On this walk I saw birds with a wide range of plumage, and in particular I thought the differences between the bright, showy colors of the Blue Jay, and the muted, inconspicuous grays and browns of the Common Redpoll were particularly interesting. It seems to me that these differences are a good example of prioritizing camouflage vs reproduction. The stunning, bright, blue tones of the Blue Jay are great for attracting mates, while the cryptic brown streaking displayed by the redpolls I saw are ideal for blending in with the wintery vegetation they tend to inhabit.

When I experimented with "spishing" on yesterday's walk, I was met with a range of reactions. I noticed that when I spished a lone chickadee that I heard calling from deep within a thicket, the bird immediately stopped calling, and as far as I could tell did not move any closer to me. When I spished at a pair of chickadees, who happened to be near a group of juncos and redpolls, a single redpoll began calling and flew up from the ground to a higher branch that was closer to me. This individual's response seemed to trigger a chain reaction in other nearby birds, as shortly after the redpoll's response, several juncos and redpolls flew up from their hiding spots to check me out, and finally the chickadees began calling and flying near me as well. I know that spishing is meant to mimic the alarm calls that songbirds like wrens, chickadees and titmice use to signal to other birds that a potential predator is present in the area. Maybe when a lone bird hears an alarm call, their typical response is to hide or flee, while birds in a larger group may have to confidence to investigate and even harass the potential predator until it leaves the area.

Publicado el marzo 22, 2021 03:22 TARDE por willbaxterbray