4/5/2018 Bird Walk in Red Rocks Park
I started my walk on Thursday, April 5th around 11:30 am. It was about 28 degrees Fahrenheit outside, but the sun was still shining. I walked in a mix of mature tree stands, young tree stands, and open fields. The first species I saw was a Downy Woodpecker that was foraging on the edge of the trail near some houses. As I continued down the path I saw a murder of American Crows that were calling to each other. As I got closer to the more mature tree stands, I stood on the edge of the walking path and saw two Pileated Woodpeckers fly into the woods. Before I could take a picture of them, I saw two birds fighting above me and one of them was a Yellow-bellied Sapsucker, which I wasn't able to identify until I got home. I went further into the woods and photographed one of the Pileated Woodpeckers for a while, and noticed to my right there was a Hairy Woodpecker that was also foraging. I continued walking and came to a younger part of the forest where I saw some Passerines, such as the Northern Cardinal, American Robin and White-breasted Nuthatch. The Northern Cardinal was calling to some other individuals in the area.
One species I observed that foregoes migration is the Northern Cardinal. The Northern Cardinal is a generalist species, and eats many kinds of fruits, insects and nuts. Birds that don't migrate have better chances of maintaining their territories year-round, and don't have to face the hazards of migration. Northern Cardinals have some behavioral adaptations to survive winter's cold; Northern Cardinals fluff up their feathers and tuck their heads and feet in to maintain body heat. Birds can also put on fat in the winter, so most species that stay in Vermont in the winter forage during the day for fatty foods, hence why bird feeders become so popular in the winter. Some birds also undergo facultative hypothermia at night to lower energy consumption.
One species I observed that is a migratory species was the Yellow-bellied Sapsucker. This species was coming from Mexico and Central America, and migrate to upper North America. This species probably started migrating north because there were more resources available up here that weren't being used up by another species. There are multiple factors that could've caused them to come back, including a change in climate (such as a change in wind patterns), timing and location changes in predation, and different food types and their supply in the environment. An advantage of this individual returning to Vermont early is that, if their food is available, they can replenish their energy stores more fully than individuals that arrive later in the season, and thus will be more fit for breeding. They can also claim territories before other individuals arrive. However, an obvious disadvantage to coming back this early in April could be that their food is not available yet; in the case of the Yellow-bellied Sapsucker, because the temperatures are still below freezing, it may not be able to access sap as well as it would if it arrived later in the spring.
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