Arquivos de periódicos de abril 2019

08 de abril de 2019

Field Observation 4: Migration

Date: April 3, 2019
Location: Centennial Woods
Time: 7:50am - 9:20am
Weather: 37°F and Partly Cloudy

During my walk through Centennial Woods, the majority of the birds that I spotted were not migrants. The Dark-eyed Junco, Black-capped Chickadee, American Crow, and White-breasted Nuthatch were all present during the winter season. It is possible that these birds do not expend energy to migrate because they are able to survive the winter conditions as long as food is available. Migration may increase the risks of survival because multiple things could occur during the migration. These individuals are forced to adapt to the harsh winter season while other individuals migrate to warmer areas that have more food resources. I did notice that these birds were more active than other times that I have observed them during the winter season. The American Crow was flying around with something in its beak and the Black-capped Chickadee was very vocal. Some individuals were starting mating displays and songs. These individuals that stay in Vermont during the winter have to regulate their body temperatures. For instance, they can utilize facultative hypothermia. Black-capped Chickadee uses this process to tolerate colder temperatures by burning less calories. Torpor is another adaptation to survive winter. Birds also have morphological adaptations, such as darker plumage for solar retention and counter current exchange to regulate blood temperature.

Throughout the walk I heard the Song Sparrow. Song Sparrows are known to migrate during the spring. The spring migration may have been triggered by longer days and increasing temperatures. The Song Sparrow was also relatively responsive to "phising". Arriving in early April allows the Song Sparrow to establish its territory before other migrants arrive. However, they also have to deal with residual winter conditions that later migrants do not have to endure. The medium-distance migrant probably came from southern areas of the United States, such as South Carolina which about 900 miles away.

Posted on 08 de abril de 2019, 05:41 PM by oliviaberger oliviaberger | 5 observações | 0 comentários | Deixar um comentário

23 de abril de 2019

Field Observation 6: Reproductive Ecology

Date: April 13, 2019
Time: 1:45-3:15pm
Weather: Rainy, cloudy and 43 F
Location: Shelburne Pond

I was rather surprised to observe multiple birds during this outing because it was raining. There were about five Mallards swimming on the pond. I heard more birds than I saw. During my walk, I did not observe a lot of reproductive behaviors. At one point I must have got a little too close to a Red-winged Blackbird nest or territory because I heard its alarming call.

Most of the trees in the woods have not yet developed leaves. There were multiple times that I observed nests, new and old. I saw a Hermit Thrush nest in a smaller conifer where it was sheltered from the elements. I was slightly surprised at how low the nest was and if I were a tad bit taller, I would have been almost eye-level. I came across the Red-winged Blackbird territory closer to the edge of the water. I was unable to see the actual nest, but I did not want to stick around to try to find it. There was also a Brown-headed Cowbird around. These individuals plant their eggs in other bird's nests. I also noticed that there were some nests in various tree cavities that were higher up in the trees.

Posted on 23 de abril de 2019, 04:02 AM by oliviaberger oliviaberger | 8 observações | 0 comentários | Deixar um comentário

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