Migration in Chittenden County

The turn of April is an exciting time for the birding community as it means that a new wave of migrants is on the way and spring warbler migration is getting ever closer. On Tuesday March 31st, I went on a “Big Day of Birding” all throughout Chittenden County to try to locate as many year birds for the county as I possibly could. One of the stops along this journey was a birding hotspot in Hinesburg, VT known as Lagoon Road. It’s nothing more than a dead end road that leads to a wastewater treatment plant along the LaPlatte River with an overgrown hay field to the west, a hemp farm to the east and a swampy solar farm bordering the actual “lagoons” of the treatment plant. It was overcast, with on and off rain showers and a high temperature of around 45 degrees. A light northwesterly breeze caused the tops of the grasses to sway back and forth gently. I spent 50 minutes at this particular hotspot and traveled a distance of 0.39 miles.

One of the resident species that I observed at lagoon road was the Red-tailed Hawk, 4 of them to be exact. These large raptors spend the majority of their winter in VT near open fields where they can often be seen perched in snags and on wires, peering over the land, listening and looking for rodents to eat. The warm feathers around their legs protect them from the cold. Limited areas of exposed apteria on this hawk allow them to endure the frigid temperatures of winter and stick it out until spring when they can breed. While some Red-tailed Hawks do migrate to areas as far south as central america, a good number of hawks have been documented overwintering in Southern Chittenden county. Another overwintering resident species that I observed on this outing was a pair of Blue Jays. These intelligent corvids have been known to store food in preparation for winter. A thick layer of down feathers and a knack for finding food sources given the opportunity allows these birds to forego migration for the most part and live in their home range and territories. While Blue Jays do not vacate the northernmost extents of their range, there are some fairly large migrations of these birds across the region in mid-May and again in late September as some proportion of the population migrates short distances north and south (eBird.org).

Probably one of the most exciting facultative migrants that I saw was four Eastern Meadowlarks, most of which were singing from the depths of the tall grass field. Since this was the second report of Eastern Meadowlark in the county this year I would be led to assume that these birds probably haven’t migrated very far and may have been birds wintering only as far south as Massachusetts or Connecticut. As soon as the snow cover melts and the ground thaws a bit, these birds make their way north. Although Eastern Meadowlarks have been known to breed in the fields surrounding Lagoon Road, I suspect that this was just a quick stopover for the birds that I saw as they were not observed by other birders on visits since then. My guess is that they continued north, following the Champlain Valley and probably are headed to the northern extents of their range, possibly the St. Lawrence River Valley or southern Quebec, CA.

Another facultative migrant that I observed was a calling Wilson’s Snipe from the wetter areas of a distant Hemp field. Along with the Meadowlarks, Snipe are reliant on the ground to be exposed and thawed in order to be able to feed effectively. Using their long beaks to probe the ground for insects, worms, and insect larvae, a Snipe would not fare well in a snow covered environment where the ground was inaccessible. This is why their migrations are typically driven more by temperature and the environmental conditions than the time of year. The bird I heard could’ve migrated from somewhere as far away as South America in theory, but probably migrated from New Jersey, which is where the northern extent of the winter range of this species lies. There is a pair of Snipe that has been continuing at this location for a couple weeks now, so I have my suspicions that these birds may actually be breeding here.

How Far Did the Birds I Saw Migrate?:
Eastern Meadowlark: ~ 130 Miles
Wilson’s Snipe: ~300 Miles
Common Grackle: ~100 Miles
Red-winged Blackbird: ~60 Miles
Northern Harrier: ~300 Miles
Killdeer: ~250 Miles
Wood Duck: ~100 Miles
Total Mileage of Facultative Migrants = 1,240 Miles

A second outing brought me to my home natural area, Saxon Hill Recreational Area. It was a bright and yet overcast day with minimal wind and a high temperature in the mid-50s. I traveled through a variety of habitats including Red-pine forests, mixed forest, hemlock forests, sandy sweet fern fields, and early successional fields. I birded for a total duration of 3 hours and 27 minutes and covered 4.23 miles in my time birding. I observed 33 species with no obligate migrants in the mix. In fact, almost all of the species I observed can be found in VT year round, with the exception of a Killdeer and arguably the blackbird species as well, including Common Grackle, Red-winged Blackbirds, and Brown-headed Cowbird.
One example of a species that is technically found in Vermont year-round, but more individuals are arriving from the nonbreeding range to the south right now is the Golden-crowned Kinglet. These tiny birds, if they do in fact decide to overwinter, tend to be found associating closely with flocks of Black-capped Chickadees and Nuthatches and seem to use other small birds as guides to help them find food in the tough times.
I can’t wait to see what the coming weeks bring for exciting migrants!

Posted on 08 de abril de 2020, 11:04 PM by jacobcbirds