15 de abril de 2019

Field Observation 5

Anotado en abril 15, lunes 18:20 por mkerner mkerner | 6 observaciones | 0 comentarios | Deja un comentario

08 de abril de 2019

Field Observation 3: Migration

On April 7th from 1:00 p.m. to 3:30 p.m., me and two other classmates went to the Urban Reserve by the waterfront of Lake Champlain. The temperature was about 50°F, but the sky was overcast and slightly windy. The Reserve is near the lake, in a slightly wooded area, which might have influenced more birds to be present during our walk. During this time, we saw a flock of American Crows, 3 Herring Gulls, 2 American Robins, a flock of Cedar Waxwings, and 3 Black-capped Chickadees. As the weather gets warmer, we are starting to see more bird species present, along with more species that migrate North in the spring and summer.
Throughout our walk, we saw 3 Black-capped Chickadees separately. The birds were most likely alone because they are a resident species that do not migrate, so it’s not necessary for them to travel in flocks. This species is able to withstand the cold temperatures of Vermont because of their ability to undergo facultative hypothermia and to change their diet based on available resources. The next species seen was the American Crow, where a flock of about 10 birds was seen circling overhead, all of them exhibiting loud “cawing” calls. They were most likely traveling in a flock because they were migrating from a warmer climate. These species are year-round residents of Vermont but may travel short distances South. This could be the reason that many more flocks have been seen recently compared to the winter time. As with the American Crow, the Herring Gull is also a year-round resident of Vermont, but some flocks may travel South for the winter. Three Herring Gulls were seen, with the first flying overhead and the next two following along a few minutes later. Both Gulls and Crows are facultative migrants, so it is likely that these individuals were in Vermont year-round, but the increased prevalence of these birds could be due to the introduction of spring.
The next two species seen are both obligate migrants, that travel to South of the United States in the winter and travel back up in the spring and summer. Two American Robins were seen in what seemed to be a display of aggression. Robins are less social during the day because they are defending their breeding territory, so this could have been an altercation over territory. The advantages of an early migration North could be that there’s more available habitat, which will lead to less altercations, but a disadvantage could be limited food sources. Unlike the Robins, Cedar Waxwings are sociable and non-territorial. A flock of about 8 Cedar Waxwings was seen flying near the tops of trees and had probably recently arrived in Vermont. Because this species is social with members of their flock, these birds probably have advantages when foraging, which is why they have migrated early. The disadvantages could be that there is not much fruit available for feeding, but this is counteracted by the increased foraging efficiency of group living.

Mini Activity: Each obligate migratory bird probably travels roughly 1,000 miles. The obligate migrants (2 American Robins and 8 Cedar Waxwings) probably travelled about 10,000 miles combined. The facultative migrants (10 American Crows and 3 Herring Gulls) probably travelled much less based on their range. I estimated these individuals will travel about 300 miles, for a total of 9,000 miles. The total range traveled for all migrant species seen would be around 19,000 miles total.

Anotado en abril 08, lunes 22:19 por mkerner mkerner | 5 observaciones | 0 comentarios | Deja un comentario

25 de marzo de 2019

Field Observation 3: Social Behavior and Phenology

On March 11th at 3 p.m., I observed the bird species present at the Gateway National Recreation Area in Sandy Hook, New Jersey. The weather was very warm (about 54° F) with light cloud coverage and strong winds. Sandy Hook is a national park on the coast of the Jersey shoreline, so many gulls were seen. The first species I came across was the Canada Goose, where I saw a flock of them occupying a grassy area at the entrance of the park. Multiple flocks of Herring Gulls were seen throughout my time there, and a Turkey Vulture was spotted flying overhead.
The flock of geese was seen near a road, most likely because this species has evolved to live near human-altered landscapes. The individuals seemed to be calling to each other with the classic goose “honk.” This could be to signal a food source to one another or to find their mates. The individuals were walking slightly, but not moving very far from one another. This could be due to the fact that this species is monogamous and mates for life, so the geese kept each other in close company. A few minutes later, a Turkey Vulture was spotted flying overhead, identified by its dark plumage and large wingspan. This individual was most likely scavenging for food, possibly to bring back to its young.
I continued walking along the water and during that time, many flocks of Herring Gulls were seen. Although there were many flocks seen, at least a few in each flock exhibited a “keow” call, which signifies personal identification of individuals. This indicates that these individuals could be signaling to each other to find certain individuals, possibly mates. Some of the birds seemed to be showing lots of movement, flying short lengths along the coast, but they mainly stayed in a flock. This could be due to the fact that it may be easier to find prey in such an open, sandy area. As with Canada Geese, it is clear that this species likes to stick with other individuals of the same species because of the benefits of group living.
Every individual seen was fairly active, most likely because it was a sunny afternoon, which relates to the circadian rhythm of each individual. The amount of activity and foraging would most likely be different if it was late at night, when most individuals rest. The plumage of a Herring Gull is very light, which could be advantageous because of the habitat they occupy. These birds are normally seen by a coast, and in my case, they were all seen on the sandy shore of the beach. This lighter plumage blends in more with the light sand color, as opposed to the Canada Goose. The Turkey Vulture’s dark plumage stands out, but there is no evolutionary disadvantage since this species has very few natural predators. In regards to the “pishing” activity, there were no small flocks of foraging birds seen during the time interval, possibly because of the location.

Anotado en marzo 25, lunes 01:41 por mkerner mkerner | 3 observaciones | 0 comentarios | Deja un comentario

08 de marzo de 2019

Field Observation 2: Ecological Physiology

On March 3rd at 11:30 a.m., I examined the bird species present at Oakledge Park for 90 minutes. The weather was slightly cool (about 36 degrees), but sunny, which made it feel much warmer, and a light breeze. The slightly warmer weather and the presence of water nearby could have influenced more bird species to be present than at other sites. I walked through several trails in the wooded areas of the park, stopping continuously to note the various bird species. During that time interval, I saw a Northern Cardinal and a Herring Gull. Two Black-capped Chickadees were observed, one by sound and one by sight.
The Black-capped Chickadee seen was in the underbrush of a tree, seemingly rustling his feathers, which could be a mechanism for the bird to keep warm. The bird was most likely resting to save its energy for foraging, since Chickadees practice foraging less during the colder seasons. The other Chickadee observed by sound was heard shortly after the first was spotted, where we heard the classic chicka-dee-dee-dee call. It is difficult to know for sure, but I assumed the second Chickadee was signaling to the other that there is food nearby, since Chickadees commonly forage in flocks. During the night when temperatures get too cold for Chickadees, the birds most likely induce facultative hypothermia, in which their body temperature drops and they exhibit little movement.
After about 20 minutes of walking and observing, a Northern Cardinal was seen about halfway up a Pine tree, making short flights from branch to branch. It was moving slightly up and down and hoping from branch to branch of a handful of trees. The Cardinal was most likely putting more energy into foraging because of the slightly warmer temperature. While observing the Northern Cardinal, a dead snag was seen nearby, but no cavities were spotted. The snag was somewhat small, an estimated 10 feet, which might explain why no cavities were present, since animals would need a larger area to make their home.
While walking close to the water, a Herring Gull was seen gliding overhead, which I could identify by the high aspect wing shape. It is unsurprising that a Gull was seen near a body of water, because this species usually nests near coasts. I am still not completely positive that it is a Herring Gull, because of the very similar shape and color of the Ring-billed Gull, and at a distance, it was hard to spot a ring around the bill. During the walk, six snags were seen in total, and more were present in the deeply wooded areas vs. on the outskirts. Of these snags, four cavities were seen on the larger trees, with each cavity correlating to a larger size of the tree. Although no animals made the cavities their home, I did see a few insects exiting when tapped on. Snags are important habitat to natural wildlife that provide protection to vulnerable species, like insects and squirrels, in harsh winter conditions.

Anotado en marzo 08, viernes 17:01 por mkerner mkerner | 4 observaciones | 0 comentarios | Deja un comentario

19 de febrero de 2019

Field Observation 1: ID and Flight Physiology

On February 4th at 1:15 p.m., I examined bird species in Centennial Woods near a stream for 90 minutes. The weather was warm (about 40°) but a very overcast day, which probably influenced more birds to be active than if it were extremely cold. The stream also might have influenced bird abundance in that area, causing more birds to be present near a body of water. During that length of time, many of the birds were identified by calls and only two species were seen visually.

The most abundant species seen was the Northern Cardinal, where I saw four in the underbrush of a Pine tree. The birds were flying from branch to branch, indicating foraging patterns of the Northern Cardinal. The Northern Cardinal exhibits sexual dimorphism, with males being a vibrant red and females being a pale brown color. This helped me determine that the birds were foraging and not performing a mating display, since there were no females present. This species exhibits short flights from branch to branch with rapid wing movements during foraging. I also noticed the round shape of the Northern Cardinal’s wings. Relative to body size, the wings of this species are large. The Northern Cardinal is easily identifiable by its bright red color, but the rapid wing movements and short flight patterns could also help in identifying this bird.

The other species seen was a Blue Jay, which was flying overhead. The Blue Jay exhibited a direct flight pattern with steady wing beats and was flying a few feet above the top of the tree line. Blue Jays are known to travel lengthier distances to forage or find twigs to build nests, so I assumed this particular bird was foraging. I noticed the Blue Jay has rounded wings with feathers spread out in a fan-like pattern. The spread-out pattern of feathers most likely increases the thrust of this species, which allows them to travel higher and farther distances. Blue Jays also have a bright blue color, which makes them easily identifiable.

When comparing the Northern Cardinal and the Blue Jay, there were many distinguishing features observed between them. While Northern Cardinals forage by short flights on the branches of trees, Blue Jays travel farther and fly overtop of trees to forage. The rapid wing beats of a Northern Cardinal can help one distinguish the species compared to the steady wing beats of a Blue Jay. Although these features help identify the birds easily, the wing shape of both species is somewhat similar. They both have rounded wings during flight with feathers that are spread out. Although the Blue Jay is slightly larger than the Northern Cardinal, if both species were flying overhead, it might be hard to determine the bird based solely on wing shape.

Anotado en febrero 19, martes 20:22 por mkerner mkerner | 2 observaciones | 0 comentarios | Deja un comentario

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