Field Journal Mar 28 Sean Devine

Start and End Times: 4-5:30pm
Date: 3/28/2023
Location: Charlotte Wildlife Refuge, Charlotte Vermont
Weather: Clear, 45F
Habitat: Mixed hardwood forest, with some surrounding houses
Species Observed: Turkey Vulture, American Kestrel, Canada Goose, Tufted Titmouse, Black-capped Chickadee, Red-winged Blackbird
The winter residents I observed were the Tufted Titmouse, Black-capped Chickadee, and American Kestrel. These species forego migration because their ecological niche allows them to remain all year. For example, a bird that only eats insects might move south in the winter so it still has a food source. Tufted Titmouse and Black-capped Chickadees can live off of seeds and other winter foods, so the time and energy of migration is not necessary. American Kestrels feed on other birds, so it can stay in the winter and prey on other winter residents. Having a food source available is only part of the problem, however, as these birds require multiple behavioral and physiological adaptations to survive colder months. Black-capped Chickadees, for example, cache food in the winter and remember where it is. They also have adaptations against the cold, including controlled hypothermia at night. All of these birds are also most active at warmer times of day.
The migrants I observed were Turkey Vultures, Canada Goose, and Red-winged Blackbirds. All three of these species are very short-distance migrants. Many Vermont geese only migrate to southern New England, while Turkey Vultures migrate to the central-Atlantic. Red-winged Blackbirds migrate short distances, nearly being a resident species, but many northern individuals do fly all the way to the southern US. These birds migrate to follow food sources, and are now starting to come back as winter ends. Snow is melting, the ground is softening and certain food sources are appearing again. Red-winged Blackbirds, for example, feed on seeds and waste grain which may be easier to find as spring starts. I didn't find any obligate migrants, but if I did there would be certain advantages and disadvantages to arriving this early. An early arrival might mean a head start on the breeding season, or easier foraging with less competition. On the other hand, freezing temps are still occurring and late winter weather could still occur and put early arrivals in tough positions.
Assuming migrations on the longer side, we could say the Red-winged blackbirds flew 800 miles from their wintering habitat. The Canada Geese could have travelled around 190 miles. The Turkey Vultures could have flown around 600 miles. That results in a total flown distance of 1590 miles.

הועלה ב-מרץ 29, 2023 06:46 אחה"צ על ידי sedevine