FJ7: Reproductive Ecology & Evolution

Time: 2:20pm – 5:45pm
Date: 04/19/2020
Weather: 50 degrees partly cloudy, rainy and overcast the last hour
Habitat: mixed coniferous and deciduous stands, abandoned farmland, with most of the trail running along streams with very rocky and root-ridden terrain. Gradual, but substantial inclines (lots of ridgelines)

For this field journal, my friend and I hiked Stevenson Brook Trail in Waterbury, VT. We hiked about 6 miles and ended up getting lost for a little while. The last hour of our hike it was raining pretty hard and I didn’t see any birds except two American Robins flying in and out of view among the trees. However, at the start of our hike, we came across an open marsh and at first, I thought I saw two woodpeckers, but as we got closer I noticed the stocky, large-headed bird with a shaggy crest and a dagger-like bill. There were two of them, and neither had any brown on them, so I’m assuming they were both male Belted Kingfishers because they are gray with a white collar and a blue-gray breast band. To create their nests, they excavate burrows in earthen banks, usually avoiding ones with vegetation. They generally choose a bank near water, but some use ditches, road cuts, landfills, and other pits to nest in. From what I saw, it looked as though both males were establishing their territory. They spend most of the year alone until they pair up for breeding season, and males will establish territories that usually conform to the shape of the stream or shoreline. These two birds were chattering loudly at each other, and dive bombing and chasing one another across the water. Belted Kingfishers are monogamous within each breeding season but form new pairs every year. The male feeds the female while courting her, and both vigorously defend their territory by chasing away intruders while giving loud rattle calls. Both males were also spreading their wings, and raising the patch of white feathers net to each eye, which is a characteristic display when they are feeling threatened. A fact I never knew about them is that people used to shoot and trap kingfishers, especially near fish hatcheries and along trout streams, to prevent them from killing fish. But, hunting them is now outlawed, and compared to other fish-eating birds, they seem to be relatively unaffected by environmental contaminants. This could be because their prey size is so small that the toxins don’t bioaccumulate as much in their tissue.

Habitat requirements differ a lot from species to species, this can be due to food availability, nesting placement, behavior, and so much more. The Stevenson Brook Trail has several abandoned farms that have been preserved because they are all in a state park. About halfway through our hike, we saw two American Robins that looked like they were nesting in the field hidden by tall grass. Robins are common birds across the continent, and you can find them on laws, field, city parks, woodlands, mountains, burned forests, tundra, etc. I’ve noticed that during the winter, the Robins tend to clump around food resources (berry-producing trees or shrubs) but recently, as the weather has begun to change, I’ve seen them much more randomly spread out. This is probably due to the fact that they are finding mates and building nests right now but also as the weather warms, insects, worms and snails are easier to find and this can result in a more dispersed placement. Female robins choose the nest sites, which are typically on one or several horizontal branches hidden in or just below a dense layer of leaves. They also nest in gutters, eaves, on outdoor light fixtures, and other structures. So, generally they don’t nest on the ground or in thickets except in western prairies. It’s possible we just saw them foraging for food, but it really seemed like they were nesting on the ground. If this was the case, they may be defending prime territory, where there is a lot of food resources and not a lot of intraspecific competition.

Before we reached the trailhead, there was about a mile of road and open area with a few trees along both sides. Before we got into the forest, I heard the distinct simple, pure 2 or 3 note whistled fee-bee of a Black-capped Chickadee. It’s possible that it was defending its territory, which I believe is prime habitat because chickadees are often found in deciduous and mixed forests, open woods, parks, and disturbed areas. This was adjacent to a mixed forest, with an opening created by the road, and slightly disturbed by human use. This chickadee may not be the fittest because it was all alone and they tend to be social birds that live in flocks, often associating with woodpeckers, nuthatches, warblers, vireos, and other small woodland species. However, I only saw this little guy for a few minutes, and there’s a chance that there were others nearby. One thing I find very interesting about these birds, besides their obvious curiosity and spunk, is that the flocks they life in use many calls with specific meanings, and they may contain some of the characteristics of human language!

Lastly, I saw a Barred Owl! I’ve never seen one, only heard a few and caught a glimpse of one flying at night while I was driving. This guy was totally hanging out, perched on a low branch of a conifer by the river, closing his eyes and swiveling his head slightly every few minutes. Barred Owls usually nest in a natural cavity, 20-40 feet high in a large tree. They may also use stick platform nests built by other animals like hawks, crows, and squirrels, as well as human-made nest boxes. They will look for a nest site as early as a year before using it and it’s not clear whether the male or female chooses the site. They may add lichen, fresh green conifer sprigs, or feathers to a stick platform nest, and will remove or flatten the top of an old squirrel nest. Cavities can be pretty deep, one recorded as nearly 8 feet deep. They are pretty territorial year-round, and chase away intruders while hooting loudly. They are even more aggressive during nesting season, particularly the females and will sometimes strike intruders with their feet!

Publicado el abril 22, 2020 04:55 TARDE por olivialiu