Will's Field Journal #5

On Sunday, April 4th, I visited Colchester Pond in Colchester, VT. I walked the entire 3 miles loop around the pond, and it took me from open field habitats (where I was hoping to find a Northern Shrike but no such luck that day), into forest that cycled between cedar, beech/maple hardwood, and hemlock dominated patches, to eventually more open field habitat on the other side. I started the walk at 12:02 pm and ended it at 1:47. Weather was partly clouded and a bit windy, 47˚ F.

On this walk I was happy to see a number of spring migrants, as well as some friendly year-round residents. It's interesting to consider how these residents, such as the White-breasted Nuthatch, American Goldfinch, and Black-capped Chickadee, are adapted to all four Vermont seasons and the unique challenges each season brings. The most obvious challenge for these residents, especially in Vermont, is dealing with winters. One of the major benefits of migration is the way it grants birds the ability to avoid, to a large degree, difficult seasonal weather. Birds like chickadees and goldfinches that live year round in Vermont must be able to develop feathers capable of keeping them warm during harsh winter months, also they must rely on high metabolic rates that are capable of generating significant warmth. Another issue Vermont residents face in winter is food scarcity. I know nuthatches and chickadees in particular have learned how to collect and store food, in tree cavities and in other places. These birds must also have more strongly developed capacity for memory, as stored food is only beneficial if it can be found again.

One particular facultative migrant I was excited to see on this walk was the Yellow-bellied Sapsucker. According to their "All About Birds" page, these birds winter in the Southeastern United States to Eastern Mexico all the way down through parts of Central America. Some birds do breed in Vermont, so it's possible that the individual I saw will be sticking around, but sapsucker range does extend up through Northeastern Canada as well as up through Central Canada and into Northwestern Canada and even a small segment of Eastern Alaska. Sapsuckers mainly eat sap from trees, which is a food source that I would imagine is pretty constant across its range, so I don't think food availability is the primary factor driving its migratory route. I would imagine climate or certain breeding habitat requirements play much more of a role. The Southeastern US and Mexico is likely getting very hot these days, which is an environmental change that could be the trigger of the sapsucker's migratory journey.

Mini Activity:
The total distance travelled from wintering site to Colchester Pond by the 6 spring migrants I observed today, is a whopping 7500 miles! I got this number from estimating on Google Maps the migration routes according to each bird's "All About Birds" range map.
Here are my estimates for each individual species:
Great Egret: 2000 miles
Turkey Vulture: 1200 miles
Yellow-bellied Sapsucker: 3000 miles
Eastern Phoebe: 1700 miles
Song Sparrow: 1400 miles

Publicado el abril 5, 2021 07:15 TARDE por willbaxterbray