Field Journal 5: MIgration

Date: 04/03/2021
Start Time: 11:00 AM
End Time: 12:25 PM
Location: North Andover, Massachusetts
Weather: 50 degrees Fahrenheit, slightly windy, partly cloudy
Habitats: my residential backyard, large trees, shrubs and grasses, various bird feeders in the yard, a lot of squirrels

This past weekend, I bird watched from the comfort of my own home (I was also driving in New Hampshire and saw a Bald Eagle so I had to include that in this post). My mom has become obsessed with bird watching and has put about 10 different bird feeders in our yard and on our large oak tree in the yard. My dog may have scared off many birds during the day but I still managed to see a variety of species during my time birding.

A majority of the species that I saw this weekend stay in Massachusetts (and Burlington) all year round. This includes the Black-capped Chickadee and the Downy Woodpecker. To me, this seems that these species of birds do not need to migrate down south for the winter months. These birds might not need migration for a variety of different reasons. They may not migrate due to the food being available for these birds as well as being physiologically adapted to the cold winter months in the northeast. In order for this to occur, the birds must have metabolism that works to have a higher body temperature which also allows for insulation through fluffing up their feathers to trap heat. Another important factor to consider is where they can stay overnight. The three birds that I found are often found in residential areas or woods where they can nest in the cavities of trees or in bird houses.

One facultative migrant that I saw in Massachusetts that will also be arriving in Burlington soon (or is already there) is the American Robbin. A facultative migrant is one that does not always migrant in the winter if the conditions are more mild than harsh. The American Robbin was most likely coming somewhere more south of New England, because some may stay in Vermont/Mass for the winter if conditions are mild, however, many do come from the Southwest and Gulf Coast Area. Food in these areas is more abundant than in the north so the reason for travel is to find an abundant source that has easier access to food. In Burlington, VT and in Massachusetts, the snow has mostly melted and the trees are starting to turn green and because it is now spring time with more warmth, there will be high productivity. This will allow for American Robbins and other facultative migrants to have an abundant source of food.

I did not see any obligate species during my time bird watching. One advantage of being an obligate migrant arriving to Burlington at the start of April would be that they are able to find and set up the best nesting/breeding site and create their own territory. This would all be able to occur before other species of birds start to show up later during the month. One disadvantage to being an obligate migrant was that it requires a lot of energy to travel long distances throughout various parts of the year.

Mini-activity:
The rough total mile for the facultative birds saw would be about 1250 miles.

Publicado el 05 de abril de 2021 por