Field Journal 5

Date: April 3rd, 2021
Time: 9:15 - 10:51
Location: Burlington Country Club
Habitat: Cleared developmental land with tree patches and water features.
Weather: Partly cloudy, 2 mph NW.
Temperature: 1 C
Species Number: 17
Total Individuals: 51

Some of the year-round species I observed were Black-capped Chickadees, Dark-eyed Juncos, To understand why birds may stay through the cold winter months, it would help to explain why others fly South in the first place. The main driving factor behind migration is food accessibility. Many birds rely on insects and seeds that are plentiful in the warmer months, but not so much in winter. To be able to provide enough food for themselves and their young, birds will fly South where food is more readily available. So, if food is less available in the winter, why are some of these birds staying? It is because there IS still plenty of food, but birds like the Black-capped Chickadee and woodpeckers are much better equipped to access it. Pileated Woodpeckers in particular have long, drill beaks that excavate trees for insects deep within. Because there is a much larger food source available to them, woodpeckers can better provide for themselves. Additionally, woodpeckers may carve out a temporary shelter in a snag for a few days to keep warm. Their ability to make a shelter virtually anywhere is another key factor that allows them to survive the winter.
There are other birds that may float between migrating and toughing out the winter. These are facultative migrators, meaning that they migrate in response to resource conditions rather than an annual point in time. If the going is good, they may stay. If the going gets rough, maybe it is better to head south. An example of these are the American Robins, which are some of the first birds to appear towards the end of winter and early spring. They tend to travel shorter distances for the winter, and this gives them access to some of the best territories when they return in the spring! Their arrival usually follows positive changes in environmental conditions like warm weather.
I am fairly certain we spotted an obligate migrant as well, an Eastern Phoebe. According to Audobon.org they leave late in the fall and arrive in early spring. Because these birds arrive so early, they get premium access to breeding grounds and food sources. The downside is that obligate migrants often don’t know what the conditions will be like when they return. This is especially true for those in Vermont, as we have wildly varying weather!

Mini-Activity: Migration distances. These rough estimates are based on the Breeding/Non-breeding territories of bird species from AllAboutBirds.org. An average point was marked on Google maps within the breeding territory and drawn to another point in the middle of the non-breeding territory. Some birds, like the Song Sparrow, are leap-frog migrators, meaning that the birds that live farther north will travel farther south than the ones that were living further south already. For cases like these, an average distance for far and short migrants was guessed at.

Black-capped Chickadees 0 km
Dark-eyed Junco 2200 km
American Robin 3000 km
American Goldfinch 1000 km
White-breasted Nuthatch 0 km
Eastern Phoebe 2000 km
Song Sparrow 2000 km
Canada Goose 3000 km

Red-winged Blackbird 1200 km
Mourning Doves 3000 km
Turkey Vulture 2000 km
Tufted Titmouse 0 km
Brown Creeper 1200 km
Mallard 1500 km
Rock Pigeon 0 km

Total 22,100 km or 13,732 mi

Publicado el abril 5, 2021 12:18 MAÑANA por bfchurch