Field Journal 4
Date: March 25, 2024
Start Time: 7:00pm
End Time: 8:00pm
Location: Converse Ct, Burlington VT
Weather: Clear skies, 38℉, 3mph wind heading SE
Habitat: Urban with occasional old growth trees that were mostly not coniferous. There were also shrubs and dead grassy plants in gardens.
House Sparrow
I saw three house sparrows eating berries in a bush as I walked down the sidewalk and I heard one calling in its chirpy high and low fashion.
European Starling
I heard an unknown number of European Starlings chattering in a tree.
American Robin
I saw three American Robins flying overhead and then heard one chirping again similar to the house sparrow but a little more song-like.
American Crow
I saw a murder of American Crows flying over head of an unknown number and they were all calling in unison.
Cooper’s Hawk
I saw one Cooper’s Hawk perched on a tree as I was walking. I distinguished this hawk based on its tail pattern and shape.
Black-capped Chickadee
I heard a Black-capped Chickadee doing its chickadee-a-dee-dee-dee alarm call from a nearby bush.
One of the most common year-round residents I've observed is the Black-capped Chickadee. This bird remains in Vermont as a result of its adaptations to cold weather which allow it to remain in a hypothermic state during the night as temperatures drop. Given this adaptation and their ability to scavenge insect eggs and berries in the winter, the energetic cost of migrating would be very large compared to the pay off of more resource availability. Another species that remains in Vermont during the winter is the House Sparrow, which utilizes berries to survive and maintains its body temperature by squeezing into tight spaces within man-made structures and tree hollows. If Black-capped Chickadees and House Sparrows were going to migrate they would be facultative migrants asa result of resource needs, but they would never be obligate migrants given that obligate migrants are essentially hardwired to migrate at the same time and place every year.
A facultative migrant that I have still seen this winter is the Cooper's Hawk. These hawks can migrate farther south in search of more abundant resources, but given the warm winter, it's likely these hawks chose not to travel south as their prey may have been in abundant levels still during the season. If the Cooper's Hawk were to migrate, it would go south to the central or southern U.S. where the climate remains warm and ground prey stays at a steady population. If there were more snow this winter so that ground prey was not as viable then the Cooper's Hawk might be more likely to go south. I didn't come across any obligate migrants, but if one of these migrants were to arrive in early April, it could be beneficial with the number of buds coming out on the trees and insects hatching. However, given the current snowfall on the ground, the weather could be a negative factor for these species as they may not have cold adaptations like the Black-capped Chickadee does so that they can survive cold nights.
Given that this week I chose to do observations around my house in order to look at the birds that’s are present in a more urban setting, it makes sense that I saw more common resident birds as they are likely adapted to a broad range of environments. Of all the birds I saw, only the Cooper’s Hawk was out if its general winter residence. However, Massachusetts had winter habitat and I calculated that Boston is about 226 miles from here where there would be winter habitat for them. The Cooper’s Hawk I saw was likely present because of the uncharacteristically warm climate that we’ve experienced this winter.
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