Field Journal 5 - Migration

Yesterday I went to the Sand Bar State Park in Grand Isle, VT. I went around 3 in the afternoon to take advantage of the sunny skies and 50 degree weather. There was a light breeze throughout my trip, but not any significant amount of wind. I pulled into the parking lot and found a habitat that was surrounded on both sides by bodies of water. There was Lake Champlain on one side, and a small bog on the other that served the purpose of a waterfowl refuge. Sandwiched between the two bodies of water was a small park area that had a sandy beach near the shore, and some scattered trees. There were some areas that had more clumped areas of trees, such as near the bog and near a residence. Overall, this habitat was a pretty open area, with some scattered vegetation.
Out of all the birds that I observed on this trip, only one of them was a year-round migrant. At least, I think so. After doing some research, I found conflicting results on whether American Robins migrate or not. It seems like some of them migrate to the Southern US, while others move around within the northeast. This species is more influenced by the abundance of food, rather than temperature. Therefore, when food is abundant, American Robins seem to forego migration. To survive in the colder climates, Robins must change their diet as well as eat more. They survive off of berries that stay on vegetation throughout the winter, such as crabapples and hawthorn berries. Robins also change the social aspect of their life, moving on from being territorial to clustering in flocks. This allows Robins to increase their foraging efficiency and have a smaller chance of being predated. As for the other species that I observed, the Canada Goose was one of the more prevalent migrants. Similar to the American Robin, the Canada Goose is also primarily driven by food resources. Beginning in the late summer, these birds fly to the southern US to find more productive feeding areas. These birds migrate in a distinct "V" formation among their flock, as I am sure we have all seen before.
Using Cornell University's "All About Birds" site, I was able to see what the migration map looks like for the species that I observed at Sand Bar State Park. Canada Geese tend to fly towards New Mexico and Texas, which is about 2,000 miles from Grand Isle, VT. Ring-billed Gulls tend to fly towards the southern US , to states such as Florida, which is about 1,500 miles from Grand Isle, VT. The migration pattern of American Crows and American Robins is difficult to decipher from Cornells website, but it appears they migrate short-distances, or stay as residents. Overall, it seems that there was about 7,000 miles round-trip that these birds traveled during migration.

Publicado el abril 8, 2020 05:33 TARDE por g_underhill