taylorehwa's Journal

I went to Mckenzie Park in Burlington, VT on Sat., April 6, 2019. I arrived at about 7:45 AM and the sky was slightly overcast. The temperature was ~40 degrees Fahrenheit. The observations mentioned in this journal post are birds that I was able to see/hear walking along Calkin's Path in the Intervale, towards Mckenzie Park.

Most of the birds that I spotted were resident species that are known to be year-long residents of Vermont such as the Downy Woodpecker, Pileated Woodpecker, Black-Capped Chickadee, Northern Cardinal, Tufted Titmouse, American Robin, American Crow, and the American Goldfinch. In order to survive Vermont's notably harsh winters, these birds must have behavioral and physical adaptations that allow them to do so. In fact, most of the birds that are year-long residents of Vermont are habitat generalists. Being a generalist means they have more options when food is scarce and don't necessarily need to migrate to find the specific resources they need. For example, both the Downy Woodpecker and the Pileated Woodpecker are habitat generalists since they are able to eat insects, seeds, and berries. Generalists may also make food stashes when weather is more favorable so that they can turn to them when resources are harder to come by during the winter. Black-capped Chickadees are known to create food stashes for the wintertime. There are also some physical adaptations that allow for better winter advantages. For example, woodpeckers' beaks also allow them to hollow out effective tree cavities for them to be protected from the harsh cold. Chickadees also have denser winter down coats to allow them to maintain their body temperature even with their small body sizes that are more susceptible to heat loss. To survive during the cooler nights some year-round birds, like the Chickadee, can actually lower their body temperatures where they go into a state of regulated hypothermia. Birds can also work together behaviorally to survive Vermont winters. For example, Song Sparrows will huddle together in groups to keep warm. On my short hike, I saw over 10 House Sparrows. These birds could likely use each other for warmth. I also saw a group of 3 Brown-headed Cowbirds that were flying around together from tree to tree. Cowbirds are known to join huge roosts with other blackbirds species to bear colder weather.

I was also able to spot some facultative & obligate migrants. I spotted two Common Mergansers taking off from the Winooski River along the trail path. These birds are mostly obligate species although some have been seen year-round in Burlington VT which would possibly make them facultative. Interior Mergansers (not on the coast) tend to migrate further than those on the coast. In the winter they tend to fly South to slightly warmer weather. Mergansers need open water so they must migrate to locations that have that available to them. So, if all of Vermont's bodies of water are frozen over they must migrate South to look for open water. A lot of them will likely migrate north to Canada to breed. Mallards are also reliant on open water (as many waterfowl species are) so many are obligate migrants. I also spotted some Ring-billed Gulls whom are obligate migrators. The Brown-headed Cowbird is a facultative migrant as many can survive in North America, including Vermont, without necessarily having to migrate. Cowbirds are extreme generalists and are known to lay eggs in other birds' nests. They also roost with one another as mentioned in the previous paragraph.

Mini Activity: After analyzing the distances of the each of the migratory species, the cumulative distance from the Intervale to the wintering locations of the species I observed was ~2,500 miles. Many of the migratory birds that I spotted only migrated across North America, and not between continents.

I went to Centennial Woods in Burlington, VT on Tues., April 23, 2019. I arrived at about 5:00 PM and the sun was out and the temperature was ~63 degrees Fahrenheit. The sun was still out but there was a slight sprinkling of rain. This limited the amount of birds observed as most were finding shelter from the rain.

Despite the limited number of actual sightings, I did hear plenty of calls in the distance. Many of the calls I heard were actually birds of the same species calling back and forth to one another, potentially seeking a mate. I heard two chickadees calling back and forth. I also heard two American Robins calling to each other. I was able to actually see two species of birds that were both in pairs. I saw two Pileated Woodpeckers, as I drew closer they began flying away tree to tree together. I also saw two White-breasted Nuthatches that were exploring holes a tree (probably from these Pileated Woodpeckers) and they stayed there for quite awhile and didn't seem to mind me sitting there for about ten minutes and watching. They were grabbing small materials and placing them inside the holes so I believe they were creating nesting beds inside the hollow holes. I don't believe these Nuthatches were a breeding pair though, as female Nuthatches usually build the nests on their own. However, both these females may have thought that this tree in particular was a great nesting place because of the already dug out woodpecker holes.

It was clear that many of the birds in Centennial were preparing for breeding season by either calling for mates, creating nests, or scavenging for food with their mates. The nesting process specifically will look quite different depending on the bird species. Pileated Woodpeckers usually nest in standing dead trees, or snags. So they would probably be located in more of the old growth patches that have lots of snags available. White-breasted Nuthatches probably will end up nesting nearby the Pileated Woodpecker nests as they use smaller holes dug out by the woodpeckers for their nests and also mainly eat insects for their diet. Chickadees also prefer to nest in abandoned woodpecker holes but often choose those made by Downy Woodpeckers as they are smaller. However Chickadees' diets are about half plant matter and half insects so they may want to choose a nesting site that is near small-seed and/or berry producing vegetation. Contrastingly, American Robins do not nest in tree cavities, but rather build nests on horizontal tree branches. They choose branches that usually have dense cover above them so that there is some insulation/protection. Their diets consist of a lot of worms, but they also eat fruits. So, their besting sites will likely be in a tree with a dense crown, and by soft soils rich in worms.

Mini Activity: I sat in the meadow-like opening that is located by the large parking lot side entrance to Centennial. Here I was able to hear a few birds but I probably would have had more luck deeper in the woods as it was slightly raining so birds would be under denser coverage areas. I heard a Hermit Thrush singing alone. I also heard an even-toned call that at first I was not able to identify until I looked it up later. It turned out to be the trill of a Dark-eyed Junco. I heard a couple more Black-capped Chickadees and American Robins along the forest edges. I saw three Mallards, and two Ring-billed Gulls fly overhead as I was in a clearing and was able to have a clear view of the sky. This activity really allowed me to be patient and critically analyze distant calls which is something I need practice with. So this activity really challenged me in a good way.