Journal #1- Flight Physiology

Date: 2/19/19
Location: Delta Park, Colchester
Time: 8:25 am
Weather: Sunny (no cloud coverage), cold (<10 degrees), little to no winds
Habitat: Forest (deciduous) broken up by wide walkway, continues on both sides of the lake

For my bird walk this morning, I went to Delta Park (Colchester, VT) at around 6:40 am. The sun was rising just as I began to make my way along the greenway, and birds slowly began to increase in visibility, audio, and frequency as the morning drew on. The most frequent species occurrence that I heard and saw was the Black-capped Chickadee, with several individuals scattered throughout the walk. I also saw several Downy Woodpeckers, with the drumming sound of their beaks being a consistent presence for the majority of my two hours spent outside. Other birds that I noticed included the Tufted Titmouse and the White-breasted Nuthatch. While I did hear an abundance of bird songs/calls in the distance throughout my walk, I did not record these species so as to avoid classification error and maintain location precision (as I will explain later).

Throughout my walk at Delta Park, I was very attentive to the movement of various birds, and analyzed how/why they may have the flight patterns that they do. Because I saw an abundance of Black-capped Chickadees, I was able to observe several individuals of this species in flight. Most of the flying that I could observe was only for very short distances (ie. between branches or trees), so I did not have the chance to encounter longer flight patterns. I found that the Chickadees had extremely rapid wing beats that remained strong and consistent until the individual reached their destination (no gliding was observed). Because of the nature of the Chickadee’s average flight routes, it seems as though their wings are more conducive to provide a large amount of thrust in very small increments. When the Chickadee flies, I can vaguely make out the outline of individual feathers, giving the impression that they have an “elliptical wing” type. Their wings are also fairly wide and not very long, which gives them a low-aspect ratio, with which they are able to create short, aggressive wing flaps which allow them to achieve maximum thrust. Because they need to be flapping wings steadily in order to move through the air, they seem to have a high amount of agility that allows them to quickly move through confined spaces (i.e. between leaves and branches).

Another bird whose flight pattern I observed was the American Robin. I only saw one American Robin during my bird walk, however I was able to watch it fly a fairly long distance between several trees. Unlike the Black-capped Chickadee, the American Robin’s flight pattern seemed to be more directional and less energy-intensive. The flight of the individual American Robin consisted of steady wing beats in a fairly rapid succession, however there were intermittent periods of gliding between these flaps. When the bird did flap its wings, the beat appeared to be much slower (and much more discernible) than that of the Black-capped Chickadee. While the Robin’s wing shape seems to be similar in shape to that of the Chickadee’s it is much longer and therefore has a higher aspect ratio. This characteristic of their wings and flight pattern could perhaps be beneficial for their foraging behaviors, as they eat many insects and worms. The longer feathers can allow them to get more lift from their primary feathers, and more easily glide/hover the ground if needed.

While these two birds have flight patterns that are fairly distinguishable from each other, I had a difficult time recognizing the differences between some of the other species that I was able to recognize in flight. I found that I could identify the smaller-sized birds (i.e. Tufted Titmouse, White-breasted Nuthatch, and the Black-capped Chickadee) when they were stationary on a branch, however when they flew overhead it was hard for me to make them out, especially if I did not get a chance to look at them before they took flight. Because I did not see a large abundance of birds, I did not have the chance to really study these different flight patterns and discern their differences through repetitive observations (which I hopefully will be able to do in bird walks to come).

In terms of being able to see more birds during my future excursions, I think I will go somewhere that does not entail too much habitat fragmentation from walkways or roads. While Delta Park is very forested and is home to many bird species, it is really only able to be explored via a wide bridge/walkway that cuts through the wooded area (especially in the winter). During my walk, I heard many (possible) bird species that I could not visually locate because they were far off the path and not able to be reached. Such birds included what sounded like a Brown Creeper and a House Sparrow closer to the developed houses next to the trail. Because I was not sure if merely hearing a species was enough justification to record it on the app, I chose not to enter these individuals into iNaturalist. I purposely went to Delta Park very early (just as the sun was rising), because I figured this time frame would allow me to see more birds. I found that as the sun rose higher and the morning drew on, more birds seemed to make themselves more heard/seen; compared to the very early morning in which I had to look very hard for distant birds. Perhaps next time I can try going a little later in the morning, or try to go in the afternoon/dusk so as to see if a different variety of birds would be out at that time.

Publicado el febrero 20, 2019 03:57 TARDE por haleyferrer