Field Journal #4
Date: 03/20/2021
Start Time: 2:30 pm
End Time: 4:15 pm
Location: Knapp Pond
Weather: Sunny with no clouds, very slight breeze
Temperature: 46°F
Habitats: Young deciduous forest, swampland, rural lawn feeders
Deep in the woods I was happy to identify my first Brown Creeper, which was silently running in circles around the top of a large tree while foraging for insects. Being at a time of day where the sun was out the alertness of this bird seemed fitting in relation to its circadian rhythm. If it had not been for its white belly and curved beak, I might have missed the Creeper due to the feather markings on its back and wings. With a mixture of melanin pigments of brown, black, buff, and white which were spread out in small streaks on its body, this bird was able to blend into the tree bark very well. Due to this I came to the conclusion that this bird’s plumage must have evolved as camouflage within the forests, advantageous in that it provides protection from predators. This was in striking contrast to the Blue Jay I had been quickly able to spot as it flew through the trees. The Blue Jay, unlike the Brown Creeper bore bright blue colors, and was easily spotted unlike its camouflaged friend. The Blue Jay was unmissable despite having only been in eyesight for mere seconds, causing me to think that this bird wanted to be seen. The head, back, and tail of the bird all incorporated bright blue colors with white bars and black stripes on the wings and tail. Similarly to the Creeper though it did have a white stomach. Perhaps this bright coloration aided these birds in finding mates, and the brighter the color, the more likely they were to be successful. It seemed as if they were showing that them being capable of staying alive despite standing out in the forest meant they were fit to be a mate.
Having realized that both the Blue Jay and the Brown Creeper had white bellies I decided to see if this trait was common in the birds of the area. Continuing on my walk through the woods I was able to spot a Tufted Titmouse, White-breasted Nuthatch, Hairy Woodpecker, and many Black-capped Chickadees which all sported a light-colored stomach. Having had time to think about this I came up with the explanation that this trait might aid birds against predators who watch from the ground as they are flying. Since the sky is a light color perhaps evolution created camouflage against it. As I watched the birds dart around, I realized that many of them had darker coloration on their wings and having remembered from lecture that melanin creates a stronger feather I thought that this created an advantage in that birds who had these darker wings had stronger wings. In relation to the circadian and circannual cycles, I realized I was not spotting any birds that had dramatic changes from their winter and summer plumages. I also kept in mind that nesting season was occurring, meaning that no birds would be molting during this energetically expensive time since it would be irrational to do so.
During my time in the woods at a point where there were no birds in sight despite me being able to hear them, I decided to try spishing and am delighted to say that it was successful. Not long after I began, two Chickadees as well as a Red-breasted Nuthatch appeared in the branches above me. Only a few feet over me, one of the Chickadees seemed to be calling back to me in its classic “chick-a-dee-dee-dee” call while turning its little head to observe me. I have been trying to answer the question of why the spishing method works for a long time, and one of the ideas I have come up with is that it could be a signal for an animal in distress. Although I do not have much evidence other than that cats can be called in with the same method, and curious Chickadees come to see what’s happening while they voice their alerting call, it is the best I have come up with. Other calls which I heard during my walk included frantic Mourning Doves who alerted each other to take off before I was near. I also was able to witness four Tufted Titmouse who were calling to each other in the trees with a song I had not recognized, interestingly they all began to converge on a single branch. Since I had been very still and silent, I did not think I was the cause for the noise, but their loud songs did make me think they were talking to one another and trying to find a mate. On top of all of these calls I heard songs coming from Chickadees which consisted of both their “Hey Sweetie” and “Chick-a-dee” songs, the later of the two is what was called to me when I was very close, so I figured that was a warning call, while the “Hey Sweetie” happened while I was farther away and unmoving. Due to the point in the circannual cycle that we are in I thought “Hey Sweetie” might have been a mating call.
Comentarios
Agregar un comentario