elenarbernier's Journal

Start time: 1:30pm
End time: 3:30pm
Date: 03/06/21
Location: Blueberry Lake, Warren VT
Weather: 19℉ and cloudy
Habitat: Trail system through coniferous forest surrounded by farm fields.

On a chilly Saturday afternoon, I headed down to Warren, Vermont to do some bird watching. The trail system that I explored was around Blueberry Lake, consisting of mostly coniferous trees as well as some open farm fields. I did not see a lot of birds that I was able to identify, which may be due to the high amount of loud families and dogs that were also there that day. However, I did see two American Crows and suspect that there were quite a bit more out of sight.

American Crows have evolved to be able to survive in pretty chilly temperatures in the winter. Some behavioral adaptations that crows display to keep warm consist of fluffing their feathers, tucking a leg or beak into its feathers, shivering, sunning, and roosting. Additionally, crows will sun themselves and go into a state called “torpor”. When in this state, they will lie on the ground with their bills open and go into a state of unconsciousness where their core temperature drops 10-12 degrees. Additionally, their heart rate and respiration are reduced which allows the bird to save 20% of its energy. This saved energy goes towards keeping the bird warm.

American crows are pretty omnivorous and will scavenge whatever they can find. The bulk of their diet in the spring and summer consists of earthworms and other terrestrial invertebrates. In the winter, they rely mostly on waste grain. This could be one of the reasons why I saw American Crows on my walk, because I was near lots of farm fields. American Crows budget their time in the winter to be awake and active during the warmest part of the day. In order to be in the sun the longest, they leave their roost sites at sunrise and hunt for food/sun themselves throughout the day. In the evening, they roost with other crows to conserve body heat during the night.

I believe that the crows that I was observing were beginning to look for a roosting place. Roosting is a behavior that crows exhibit where they gather in large flocks at night to conserve body heat. Because the temperature was already starting to drop so rapidly, and it was a pretty cloudy day, the crows that I was observing may have been beginning to do just that.

Snags are important in the winter because they provide shelter for birds and other wildlife to spend the night in. Sleeping in a cavity can trap body heat, and raise the body temperature of a bird. Some bird species that are likely to use them are smaller songbirds that need to rely on sheltered areas to maintain their body temperature At the end of my walk, I observed two cavities. One was larger with a few holes in it and had a good-sized cavity. The other had a smaller cavity, which I suspect a woodpecker made.

Start time: 12pm
End time: 2:45pm
Date: 03/18/21
Location: Lone Rock Point, Burlington VT
Weather: 29℉ and partially cloudy
Habitat: Semi-urban cliffs/wooded area on Lake Champlain, with a large beach nearby.

The Herring Gulls that I spotted were flying along the water. I ended up seeing five in total, but not all in a group. They flew mostly by themselves, and sometimes in pairs. I believe they were looking for food and were probably heading to the more populated beach area to scavenge. They did not seem to be interacting much as they flew. I also saw a pair of what I believe to be Common Mergansers. They were swimming in a pair so I can assume they were a mating pair. They stuck close together as they swam. In terms of visual cues, this pair of common mergansers definitely were indicating that they were focussed on each other and intended to swim together.

The Common Mergansers were definitely displaying their spring plumage, although I could not see them that clearly (they were very far away). The male most likely had his breeding plumage on display. This consists of a green head and a white body with black wings. A male Common Merganser’s non-breeding plumage resembles the females’ plumage - a brown head with a grayish body.

On the other hand, Herring Gulls do not have any significant changes in plumage year-round. There is also no difference in plumage between males and females. However, males are generally larger than females. One reason why Herring Gulls might not have a difference in plumage between males and females is because they are both very attentive parents. Usually, birds with more color variation between sexes generally have only the females take care of the young. This is because bright plumage may attract unwanted predators to the nest. Plumage that blends in better to the surrounding environment is better suited for taking care of young.

One of the Herring Gulls that I was observing was definitely foraging for food. It was skimming low over the water, in addition to heading in the direction of a populated beach. This makes sense due to the fact that it was the middle of the day. Even though the temperatures are generally increasing, it still gets pretty chilly during the evening and night. This gull is foraging for food during the day because it does not have to expend as much energy keeping warm, and therefore can use up more energy to find food. This circadian rhythm is enforced by the amount of daylight produced by the sun every day.

For the mini activity, I made a repeated “pshh” sound. This alters the behavior of small birds because it resembles a call that would be made by a fellow small bird. Birds want to know who is in their territory/habitat, so they are curious about the noise and are enticed to react to it.