Field Journal Post 3: Social Behavior and Phenology

This week I did my bird walk in the Cheslin Preserve in Embreeville, Pennsylvania. This is an extensive grassland area with a forested plot around the meadows. Today it was about 50 degrees and partly cloudy. The day before it had rained quite heavily all day and the ground was still quite wet.
I started walking through the meadows and saw numerous grassland birds including Horned Larks, Eastern Bluebirds, and Tree Swallows. I then went into a woodlot and saw many more generalist and forest species. Here, I was able to notice both species and behavioral changes. These changes were obviously linked to the forested area and sub-habitats found within the woodlot.
In terms of communication, I saw a fair amount of direct inter-species communication between the Eastern Bluebirds and Tree Swallows as they dove at each other in competition for the few bird boxes along the meadows. This was a much more obvious communication than others. They were calling and diving, making their communication between the species abundantly clear. These two birds have relatively similar coloration as well. Both are colored with structural pigments that produce two different shades of blue. These colors are also much brighter on the males of each species, indicating that there is some sort of mating aspect to their coloration. There may also be an evolutionary advantage for these aerial insectivores to have white bellies and blue backs and wings.
I chose to focus on one male Northern Cardinal. It was perched on a branch mid-way up a tree calling out and looking around quite alert. This mating or territory call most likely greatly influences the circadian rhythm of the Cardinal because it dictates how the bird spends much of his day. In terms of circannual rhythm, the mating season is a very significant part of the year that the bird spends much of his time and energy on when it is occurring.

Posted on 25 de março de 2020, 12:35 AM by lukebeeson