Käyttäjän polimpio päiväkirja

On March 5th, there was an overcast (about 60% cloud cover) with a light wind. When I began birding, it was 10:24 am and 14 degrees. To combat these below freezing conditions, the winter plumage is present in many birds to help retain body heat. Some species, such as woodpeckers and some pigeons, also utilize snags to rest in for the winter or store food. During my walk, I unfortunately did not encounter any species nesting or resting in a cavity. I did see a few snags and kept my eye out for what birds were present in the area, but came across no significant relationship or correlation which could be due to the timing of the day, the weather, or the location as I was near the lake.

When I was down by the shoreline, I saw many Mallards and began thinking about how they combat the cold water temperature of the lake. Mallards have evolved to control and limit the amount of heat they lose through their feet by controlling the blood circulation between the arteries and veins. This adaptation is similar to that of Herring Gulls, which were also abundant by the water. While the mallards seemed to be budgeting their time by resting, the gulls were very active: soaring and actively watching the water on the docks.

Overall, it seemed as if most of the species I encountered were active as they were seen flying, eating, calling, or active in a tree. I wonder if this is due to the fact that it was morning and they use their energy while light since it gets darker earlier in the winter and temperatures drastically decrease after the sun goes down. I saw robins feeding on berries, as I did in the previous journal, which is indicative of winter habits since in the summer robins tend to find insects in soil.

On Sunday March 21st, I began my observations at the waterfront in Burlington, VT at 9:30 am and ended at 11:00 am. There was 100% sun and it was 37 degrees. There were obvious signs that is was the second day of spring: birds being very vocal and very active. Many house sparrows were perched up high, basking in the warm sun and observing all of the neighboring species. It seemed as if they were resting, perhaps they just finished foraging or they wanted to recharge in the sun. This behavior fits into the House Sparrow's circadian as well as circannual rhythm as they are adjusting to day length and using their "body clock" that is stimulated in the pineal gland. House Sparrows and all bird species are going through physiological changes as spring is arriving and migrants are coming back to Vermont during this molting period.

I was excited to be able to see Common Mergansers, both male and female, as their plumage is very distinct and unique. This plumage may be beneficial for mating and their behaviors out in open water, especially when compared to Ring-billed Gulls that are very plain in plumage. However, this plain-white plumage benefits that gulls as it limits the contrast between the bright sky and their bellies, disgusting them from their prey in the water. The iridescence present in mergansers may be beneficial to hide them from their own predators, while also repelling water.

When located near trees and more inland, I tried spishing. Based on the fact that I did not see any flocks of birds, I'm assuming it scared off any species that were close by. This could be because it may come off as a sound of aggression. It may be enticing to small birds as they can group together and ward off a predator. They may also believe it is the sound of something they consider familiar or safe.