Field Journal 4: Social Behavior and Phenology

Date: 03/21/21
Location: Intervale, Burlington VT
Weather: Sunny, clear skies, 45 degrees
Habitats: Agricultural fields, Shrubby forest edge, river corridor, floodplain forest.

The birds were out in full force today! Many migrants coming back for the Spring. Birds are social species and I was able to witness some interactions today. The most dynamic interaction I saw was between two Hairy Woodpeckers. One woodpecker was probing on a downed tree, the other one approached the same tree only to be chased off. The first communicated its desire for the second one to leave by loudly vocalizing - rapid, harsh notes - and by flapping its wings at the other bird. This is an example of intraspecific competition and territoriality. It may be more energetically beneficial for the woodpecker to expend energy defending a territory if there is good food there. I observed many Black-capped Chickadees, White-breasted Nuthatches and Tufted Titmice that were all occupying the same area. They seemed to tolerate and even be drawn into the same area. I also observed three chickadees that seemed to be chasing each other. This could be a breeding/courting activity. The main way that birds seem to communicate is through their vocalizations. They vocalize to attract mates and establish territory. I reason that this group of birds was singing to mate rather than defending territory because there were many birds i the same area. One individual bird I focused on was the feeding Hairy Woodpecker. It was tapping into the bark of a downed tree. This feeding behavior fits into the context of its circannual rhythm because food is becoming increasingly more abundant. Hairy Woodpeckers feed on insects within trees. These insects' populations blossom in the spring and sustain the woodpeckers. This influx of food allows the Hairy Woodpeckers to breed (a very high energy activity) at a time when there is plenty of food.

The Mourning Doves that I saw were overall tan with black spots on their wings. Their plumage nearly perfectly matched their surroundings. I observed them feeding in an area of twigs and underbrush. Their plumage pattern likely evolved to camouflage them in these environments. On the other hand, the male Northern Cardinals that I saw were easily spotted with their bright red plumage. Their plumage supports a different evolutionary purpose: attracting mates. Male cardinals that have brighter and better looking plumages are more likely to be sexually selected by a female and will pass on its genetics. This benefit must outweigh it being easily sighted by predators.

I experimented with spishing among two different foraging flocks. The first group had Black-capped Chickadees, a Tufted Titmouse, and House Sparrow in the area. When I spished, it seemed as though the birds stopped singing and listened, and then began their calls again with even more energy. The second group had Black-capped Chickadees and White-breasted Nuthatches. When I spished here, I noticed a few of the the birds move closer - in fact, two of the chickadees came to a tree right above my head! They seemed very curious.

Julkaistu maaliskuu 22, 2021 03:36 AP. käyttäjältä gthiggins