Archivos de Diario para abril 2020

09 de abril de 2020

April 8, Migration

April 8, 2020, 4:00-5:30p
Weather: Mid to upper 50's and sunny.
Location: The Intervale Center, Burlington VT
Habitat: Started in an urban area, moved to an heavily human-influenced forested floodplain. Very sandy soils, and sparse underbrush. Many deciduous trees, with plenty of large snags.

For this bird walk, I decided it might be interesting to return to my first birdwatching site from this class on the trails in the Intervale, and observe the changes between the winter and the beginning of the spring. The walk started off well, as I spotted a cardinal outside my window while I was getting ready to leave, and then a pair of blue jays almost immediately after leaving the house. I started by walking through a small graveyard which had some good bird activity. I saw a number of starlings, which are residents to Vermont, and a few robins, which are facilitative migrants. I have seen a couple of robins around Burlington this winter, but there seemed to be a lot out of them out today. Eventually I got down to the Winooski river, and my next fun sighting was a group of 4 common mergansers in the water, though they moved on before I could look too closely at them. There were a couple of other memorable moments throughout the trip, one being closely investigating a pair of noisy tufted titmice in some shrubs, as I feel I have only ever really seen them from afar. The other was a bird I was unable to identify, which really vexed me. I first thought it was the wood thrush we talked about in class today, but the coloration wasn't quite right. It looked a lot like a song sparrow, but much smaller than I picture a song sparrow being. The size reminded me of the winter wren, but it didn't keep its tail cocked in the same way.

When looking at migration, most of these species, including the other species listed in the observations, are residents or short distance migrants. The true residents need to be tough or resourceful enough to find food throughout the winter, need adaptations like the brainpower of a crow to find food, or the memory of a chickadee to remember where you hid it during the summer. Also, they are all birds that spend most of their lives above dry land, many of them reside in the forest, which may help keep them safe from some of the harsher winter conditions. Our longest distance, and only obligate migrants, on the other hand, were both waterbirds, the Canada goose and the common merganser; and it makes sense to fly south if your food source is going to be trapped under a layer of ice for 6 months. Others are somewhere in between, like the American robin, which generally migrate short distances. This also seemed to have an effect today, as I saw robins on many different occasions, though many were close enough that I didn't want to double count. It might make sense that there may be more robins here as the weather warms, or I could just be experiencing conformation bias. Either way, based on the birds we saw today, habitat type may be one reason for birds to migrate, as freezing temperatures can leave some waterbirds without many options.

Estimating the distances the birds had flown to travel here was challenging. I chose 4 that migrate at least a little bit: the Canada goose, the common merganser, the American robin and the song sparrow. None of these migrants have travelled very far yet, though the former 2 may have a long journey ahead, which is why to makes sense that we are seeing them here so early. Among the 4 species, I estimated that they had traveled a total of about 1500 miles to get here, though this number has an enormous margin of error.

Anotado en abril 09, jueves 01:11 por lucasferrier lucasferrier | 9 observaciones | 0 comentarios | Deja un comentario

16 de abril de 2020

April 15 Post

Date of observations: 14 April 2020
Time: 4:00-5:30 p
Weather: clear, and cooler than it had been the past few days. Followed a few days of rain
Location: Battery Park and surrounding areas, in Burlington VT.
Habitat: urban landscape, large sparse deciduous trees, large shrubby/brushy habitat, human-maintained grasses, lake shore.

For this birding session, I took a walk to Battery park to look for birds over Lake Champlain. Though I did not spot some of the waterbirds I was hoping to see, I got to watch some of the more common species in a different habitat than I had seen previously.

Anotado en abril 16, jueves 01:32 por lucasferrier lucasferrier | 6 observaciones | 0 comentarios | Deja un comentario

23 de abril de 2020

April 22 Journal Entry

Date: April 22, 2020. 3:30-5:00 pm.
Weather: Mostly overcast with temperatures in the upper 30s to low 40s, with high winds.
Location: Medium sized planned forest in Essex Vermont.
Habitat: tall, uniform conifers, with lots of low underbrush, but very little vegetation between the floor and the canopy.

This time around, I got unlucky with my area selection choice. A friend and I went out to a small trail in a little planned forest for timber harvest. The area was very interesting for humans, but my guess is that this would be poor habitat for many bird species, and the heavy wind certainly wasn't encouraging flight. The trees were tall but sparse, providing little cover, and swayed heavily in the wind, creating a very unstable canopy. I did not see many birds, but I will d omg best to analyze those I did see.

First, the only bird I saw that seemed like it might be in the business of mate selection or territory defense was one singular robin. It was sitting on low branches and singing near us for a while, and I heard its song nearby for a while afterward. It didn't seem to have a mate, which has not been the case for most other robins for me this year, and it could be due to the poor territory. Since I did not see any other territory-defending birds out today, I decided to do some research on the mating habits of corvids, since I had such an interesting experience with them today (I actually managed to identify a raven because it was next to 3 crows). We had learned in class that crow tend to flock in the winter, and I wondered if that was true for the breeding season as well. All About Birds says that generally these flocks tend to split into smaller family groups, who work together to raise young, and they did not mention defending territories. Ravens, however, seemed to follow the common model more closely, defending large territories and generally practicing social monogamy. It seems unlikely that either of these species would have nested in this area, as tree branches were not large enough to give a lot of ample support, and windy conditions moved the trees too much to be stable.

For my mini-map, there were not a lot of interesting sounds around. I did my best here, but I don't know some of the species. The light green was either a crow or a raven, and the blue in the left corner was the robin.

Anotado en abril 23, jueves 01:37 por lucasferrier lucasferrier | 5 observaciones | 0 comentarios | Deja un comentario