Ecological Physiology

Today I went for a bird walk starting at 4:09 pm and ending at 5:42 pm. I was out for about an hour and a half. My last walk I went during the middle of the day, so I went later in the afternoon this time to see if it would impact the number of birds I saw. Today was warm at around 40 degrees Fahrenheit. When I started the walk it was sunny, but it got progressively more overcast and dark as the sun started to set. The temperature also fell a little bit during this time. There was a slight wind coming from the northwest at 10 MPH. I started my walk in the Redstone Campus at UVM. There are many buildings and people here, and some would classify this as an urban location. I then walked onto the paved path that parallels the track, and from there moved to the golf course. The golf course provides a variety of habitats, from open to stand alone trees, to more forested areas.

While on Redstone I moved towards Simpson Hall because I often see birds here when I walk to class. The seagulls were all over the place and calling to each other. I sat next to some of the shrubs that are located along Christie Hall. Here is where I noticed the chirping of the House Sparrows. Some flitted out of the shrubs and into some nearby trees. I also watched the European Starlings up in the trees. They were clicking. I decided that I wanted to head to some more forested area, so I made my way through the Redstone campus and onto the golf course. At first I had trouble locating any birds, but after remaining still for a bit I began to hear some song. I followed the song until I encountered a White-breasted Nuthatch perched high in a deciduous tree. I continues to listen for birds, and follow my ear to them. This was an effective strategy. I made my way through much of the golf course, jumping between the more forested patches as I wasn't finding any birds in the open grassy fields.

Today was a fairly warm day, so maintaining body temperature was likely not as much of an issue for many birds. However, I did notice that the House Sparrows were perched within a shrub. The shrub could be acting as protection from wind. This is a behavior utilized by birds to maintain body temperature. The European Starlings and House Sparrows were spending most of their time simply perched in their trees, resting, suggesting that they are trying to reduce their energy output so that they can allocate this to maintaining their body temperature. Also, they could have done their foraging earlier in the day and were settling down for the night (the sunlight had an orange glow that suggests the sun was soon to go down and night was approaching). Contrastingly, the Ring-billed gulls, White-breasted Nuthatches, Black-capped Chickadees, and American Crows were often in flight. I noticed in particular that the White-breasted Nuthatches spent a lot of time foraging. Perhaps since it was a warmer day, they had to allocate less energy to staying warm and could therefore spend more time feeding/foraging. They were tapping at the bark which was surprising. I assume they were foraging for insects or seeds, but I would not expect many insects to be out yet. I would have expected to see them in some of the trees that still bear fruit, as was the case with the House Sparrows. I would think to find most of these species roosted in trees further away from human reach or within the shrubs. However, on the edges of Redstone campus, they would be at less risk of human influence, but perhaps protected from predators who do not want to approach the highly human-influenced setting.

I did see a number of snags, but I did not notice any birds utilizing these snags. However, in the bigger snags there were larger cavities which could be associated with greater bird abundance. If the birds utilized huddling to maintain body temperature during the cold nights, more birds would be able to fit into a large cavity, resulting in higher abundance here during nightfall as they find their places to roost. Snags are important because they provide protection from the elements and ground predators. I would expect to find birds that cannot go into torpor or controlled hypothermia in here as a way to maintain their body heat and huddle with others. Small birds may be more likely to use them because they have a higher surface area to volume ratio, meaning that it is easier for them to lose heat to the environment.

Publicado el marzo 5, 2020 11:43 TARDE por emerrylees