Field Observation 3: Migration

On April 7th from 1:00 p.m. to 3:30 p.m., me and two other classmates went to the Urban Reserve by the waterfront of Lake Champlain. The temperature was about 50°F, but the sky was overcast and slightly windy. The Reserve is near the lake, in a slightly wooded area, which might have influenced more birds to be present during our walk. During this time, we saw a flock of American Crows, 3 Herring Gulls, 2 American Robins, a flock of Cedar Waxwings, and 3 Black-capped Chickadees. As the weather gets warmer, we are starting to see more bird species present, along with more species that migrate North in the spring and summer.
Throughout our walk, we saw 3 Black-capped Chickadees separately. The birds were most likely alone because they are a resident species that do not migrate, so it’s not necessary for them to travel in flocks. This species is able to withstand the cold temperatures of Vermont because of their ability to undergo facultative hypothermia and to change their diet based on available resources. The next species seen was the American Crow, where a flock of about 10 birds was seen circling overhead, all of them exhibiting loud “cawing” calls. They were most likely traveling in a flock because they were migrating from a warmer climate. These species are year-round residents of Vermont but may travel short distances South. This could be the reason that many more flocks have been seen recently compared to the winter time. As with the American Crow, the Herring Gull is also a year-round resident of Vermont, but some flocks may travel South for the winter. Three Herring Gulls were seen, with the first flying overhead and the next two following along a few minutes later. Both Gulls and Crows are facultative migrants, so it is likely that these individuals were in Vermont year-round, but the increased prevalence of these birds could be due to the introduction of spring.
The next two species seen are both obligate migrants, that travel to South of the United States in the winter and travel back up in the spring and summer. Two American Robins were seen in what seemed to be a display of aggression. Robins are less social during the day because they are defending their breeding territory, so this could have been an altercation over territory. The advantages of an early migration North could be that there’s more available habitat, which will lead to less altercations, but a disadvantage could be limited food sources. Unlike the Robins, Cedar Waxwings are sociable and non-territorial. A flock of about 8 Cedar Waxwings was seen flying near the tops of trees and had probably recently arrived in Vermont. Because this species is social with members of their flock, these birds probably have advantages when foraging, which is why they have migrated early. The disadvantages could be that there is not much fruit available for feeding, but this is counteracted by the increased foraging efficiency of group living.

Mini Activity: Each obligate migratory bird probably travels roughly 1,000 miles. The obligate migrants (2 American Robins and 8 Cedar Waxwings) probably travelled about 10,000 miles combined. The facultative migrants (10 American Crows and 3 Herring Gulls) probably travelled much less based on their range. I estimated these individuals will travel about 300 miles, for a total of 9,000 miles. The total range traveled for all migrant species seen would be around 19,000 miles total.

Posted by mkerner mkerner, April 08, 2019 22:19

Observations

Photos / Sounds

No photos or sounds

What

American Crow Corvus brachyrhynchos

Observer

mkerner

Date

April 7, 2019

Photos / Sounds

No photos or sounds

What

Herring Gull Larus argentatus

Observer

mkerner

Date

April 7, 2019

Photos / Sounds

No photos or sounds

What

American Robin Turdus migratorius

Observer

mkerner

Date

April 7, 2019

Photos / Sounds

No photos or sounds

What

Cedar Waxwing Bombycilla cedrorum

Observer

mkerner

Date

April 7, 2019

Photos / Sounds

No photos or sounds

What

Black-capped Chickadee Poecile atricapillus

Observer

mkerner

Date

April 7, 2019

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