Bird Walk April 25 in the Intervale

On Wednesday, April 25th I walked through the Intervale in Burlington, Vermont, from 11:20am to 12:30pm. The weather today was rainy, but around 55 degrees Fahrenheit. The habitat here varied quite a bit; it starts off in a secondary growth forests with big cottonwood trees and sandy soils. The trail followed the Winooski River, and across the river was marsh habitat. Towards the end of the trails are large, open fields that provide great habitat for edge species.

I saw a great range of species today. Although, I felt that I didn't see a lot of the birds I was hearing, which may be due to the fact that across the river, trees were being cut down and might've scared them off. However the species I did see were exhibiting a lot of different behaviors. First of all, I saw three Hairy Woodpeckers fighting over territory; I saw a male chase off two other Hairy Woodpecker's, making loud calls as he did so. They were definitely fighting over prime territory, because they were right next to the river, and there were a lot of small snags in the area which other bigger woodpecker species, such as the Pileated, probably wouldn't use. The male I saw fighting off the others was probably of the highest fitness, because he could spend that energy fighting rather than foraging, and will probably get more females than the individuals he chased away (assuming they were also males). But what is prime territory for these Woodpeckers might not be prime territory for everyone; a Mallard might think prime territory is the marsh across the river, and prime territory for a Common Grackle could range from a forest edge to a city park.

I also saw an American Robin gathering materials to build a nest. In it's beak it was carrying straw or dead grass, which it probably got from the farmed fields a couple meters away. Robins use straw and twigs to build their nests, and I saw a completed nest at eye level in a tree on my walk as well. The American Robin could get materials for its nest anywhere in the woods or the field that had twigs or straw, which were not limiting resources. However not every species builds a nest in the open such as the American Robin; a lot of other birds such as the Black-capped Chickadee, Tufted Titmouse, Hairy and Downy Woodpeckers, and sometimes Winter Wrens will use cavities in trees or other natural cavities for nesting. I also saw a pair of Brown-headed Cowbirds, which don't have to build nests; they're brood parasites, and will lay eggs in other birds nests for them to raise. I could tell the pair of Cowbirds I saw today was a breeding pair because the male was following the female from branch to branch and singing to her and puffing up as he did it.

My mini activity was pretty successful this week. Because the trail I was walking was fairly open, it was easy to follow where sounds were coming from. For example, when I was walking I heard the Northern Flicker from all the way across the river to my right, but could detect that an Eastern Phoebe was right above me.

Posted on April 25, 2018 11:16 PM by apbray