Archivos de diario de marzo 2020

03 de marzo de 2020

Journal #2: Ecological Physiology

On Saturday, February 29th, 2020, I went into Red Rocks forest from 2:00 PM until 3:30 PM. The temperature was around 19º F and it was cloudy with no wind. This forest is an expansive piece of land and ranged from deciduous to mixed deciduous and coniferous. This park is next to Lake Champlain, and as the name states, it is fairly rocky at the top resulting in sparse trees in some places. The species I observed were Black-Capped Chickadees, American Crows, a Red-bellied Woodpecker and a Tufted Titmouse.
The most abundant species I observed was by far the Chickadee with 15 individuals observed over the course of my outing. Their behavior was interesting because I saw no chickadees in the parts of the forest with more dispersed trees, and as well as parts with majority shorter trees. In both coniferous and deciduous trees, the chickadees stayed on the crests, flitted back and forth between trees often, and never stopped calling. I though that this could be a way to produce and retain body heat because the constant movement between trees would force their body to work to keep them moving, generating heat. The singing could do a similar job because their breasts move when the call was made, which is a movement that could generate body heat. I also observed them staying in the treetops which could act as a buffer to the cold winds coming off the lake, or just a shield from the cold. The coniferous trees still had needles on their tops, which could play a role in conserving the chickadees body heat. Additionally, being only in dense forests groves would do more to protect against wind then the single trees.
Over the course of my observation, I saw around 6 snags. There was one very large one that had cavities in it, but they did not appear to be made by animals. I heard a Red-bellied Woodpecker around this snag, but I was unable to ascertain if it was in the snag or the surrounding trees. I looked in some of the cavities, but they appeared to be empty. However, I saw a significantly smaller snag that was riddled with what looked like woodpecker burr holes. There were shavings in the tree that looked like they might be nest cavities, but I was unable to determine if there were any woodpeckers in the snag at that time. The main use for the snags looked like they were either for nests, or as a food source of the bugs that live within snags. In the winter months, snags could be important food sources because many other insects might die off in the cold and snags create livable environments. They also could act as shield from the cold because inside a tree is warmer than in the exposed air. The snag cavities were all over the site, so I could not find a direct correlation between snag density and bird abundance, but the snags that had cavities in them were generally in areas where I could at least hear birds.

Posted on 03 de marzo de 2020 by iadeslaw iadeslaw | 4 observaciones | 0 comentarios | Deja un comentario

18 de marzo de 2020

Journal #3: Ecological Physiology

From 2:00-3:30 PM on March 9th, I sat on the lawn of the Washington Monument in Washington DC, and observed birds in a grove of cherry trees, and two oak trees. It was 72º and sunny with clear skies and minor amounts of wind. There were people around but the spot I was in was not overrun with tourists. The breeze was coming off the bay that sat a couple hundred meters from where I was. Even though DC is a city, it has many trees so I was able to observe bird species in an environment other than the forests of Vermont. I saw European Starlings, House Sparrows, and Ring-billed Gulls.
The way the different species interact with each other varied. In both the sparrows and starlings, there was definitive flocking behavior, but the starlings appeared to have more of a hierarchy. For starters, only the starlings were making sounds at all. I could hear them all throughout the trees, on the ground, and in the air. And although they were in a group, there was tension. I observed an individual pecking at an apple on the ground, and then another starling came, made calls at the first individual resulting in the first bird's departure. This looked like a show of dominance which makes me believe that the calls from the starlings were a warning of territory control and dominance. I think that even though all these individuals were cohabitating they were not a cohesive unit, and made “threats” at each other to show who was in control. Alternatively, I saw a large group of House Sparrows (around 10 individuals), all in one location under a cherry tree, foraging, and not making a single sound. There was no chirping, no threat calls, no songs. They were all simply eating under a tree, taking dust baths, and sharing the unlimited resources. This looked like more cohesive flocking than the starlings.
The plumage of the Ring-billed Gull and House Sparrow are quite different. The gull is almost completely white while the sparrow is various shades of brown. Although these species can exist in the same or similar habitats, they occupy different niches. Gulls are water birds, so they need much more sleek feathers to cut easier through winds, and their white coloring could help with refracted light off the water and protect them from predators. Sparrows, on the other hand, do not need this advantage. They are living in trees, shrubs and cities and really just need to blend in. Their brown coloration helps them blend into trees and their down feathers help keep them warm. They do not need to fly long distances so it is not as crucial that they be as streamlined as the gull. These two bird species need to adapt to different circumstances because they are not concerned with the same predators or living circumstances.

Posted on 18 de marzo de 2020 by iadeslaw iadeslaw | 3 observaciones | 0 comentarios | Deja un comentario