Field Journal 5: Migration

Date - 4/3/21
Start time - 9:15 am
End time - 10:51 am
Location - UVM Campus and Burlington Country Club
Weather - sunny, no clouds, 32 degrees F, 2mph NW wind
Habitat(s) - marshy retention ponds with phragmites and staghorn sumac, Eastern white pine stand, grassy mown fields

Many of the year-round Vermont residents we spotted on the field trip, like Black-capped Chickadees and Tufted Titmice, have adapted for the harsher winter conditions. They are able to find food here in the winter, either from feeders or nuts and fruit in the trees. Some have also adapted to go in to torpor or regulated hypothermia to survive the night temperatures below freezing and conserve energy. This is a useful alternative to the energy expensive migration to the southern US or Mexico and South America.

Facultative migrants have started to reappear in Burlington. One specific example we saw on this trip was the Canada Goose. Most geese fly to the southern US for the winter, if their ponds and lakes up here freeze over, and come back up north for breeding. We saw an example of this cycle when we were out and found a male and female goose with a nest and eggs. As temperatures have gotten consistently warmer the past few weeks, water sources have thawed and geese have been able to settle in to their breeding grounds. We did spot one obligate migrant, the Eastern Phoebe. They come up from the south early on, possibly to get a jump on other spring migrants and have their pick of insects as they come out with the warm weather. One disadvantage to migrating this early might be that the warmer temperatures that drive the birds to migrate back north could be a fluke. Temperatures may drop back down to freezing and the birds might not be able to handle it.

Many of the migrant birds we saw here have travelled over a thousand miles between their farthest non-breeding ground and Burlington, including the Phoebe and the American Goldfinch, the farthest ones going all the way down to southern Florida. Other birds, like the Red-wing Blackbird, went relatively shorter distances, going about 750 to 800 miles south. Totaling all these numbers up, these birds travelled more than 10,000 miles.

Publicado el 05 de abril de 2021 a las 07:50 PM por emma2forsythe