Social Behavior and Phenology-Meghan Murphy
Burlington Intervale (3/24/19)- Field Notes
This week’s birding excursion took place at the Burlington Intervale Calkins trail on Sunday, March 24th. One other person, Kayley Dillon, was present as well, so our observations are the same, but all additional work will be completed independently. There was very little wind, with a sunny and clear sky, and the temperature ranged between the high 30s-40°F. We began our birding excursion at 9:22am. The majority of the trail that we traveled on was forested with riparian tree species such as Eastern cottonwood, ash trees and silver maples, and the Winooski River flowed close to the trail. Near the start of the trail, we were able to hear and observe a White-breasted Nuthatch, two American Crows, and a Northern Cardinal. We moved closer to the water to observe a flock of Mallards and were treated with a sighting of a Brown Creeper working its way up a large forked tree. Two sparrows that we later determined to be Song Sparrows landed in a nearby bush. There was a drumming sound behind us soon afterwards, and there was a Hairy Woodpecker working steadily away at a medium-sized snag. It was at this point that my phone, in a display of bitterness against the cold weather, powered completely down and took with it my only means of taking pictures for the remainder of the excursion.
There were multiple Mallards that flew overhead, usually either in pairs or by themselves. About four different pairs of Canada Geese were paddling in the river, and a large flock of about 20 individuals flew overhead. There was a large flock of both Mallards and Canada Geese near the shore across the river, with several Mallards resting on a fallen tree in the water. A loud call brought our attention to farther into the woods, and we were able to see the largest Hairy Woodpecker that I have personally ever come across. It was joined by two other Hairy Woodpeckers with two going to the same tree, and one occupying a different tree. A Downy Woodpecker was sighted not too far from this area. We saw a male Northern Cardinal land in a bush and heard another one close to us. An attempt at pishing attracted three Black-capped Chickadees to a nearby tree.
At this point, we crossed to a different trail that led us to an open field flanked by forest and that would eventually lead to a road. In the field there were about eight American Robins foraging and wandering to the middle of the trail. They were accompanied by about three different sparrows of which we could not confidently identify the species. These sparrows soon flew into dense bushes and foraged in this area. A male American Goldfinch in his brilliant breeding plumage perched proudly on a tall sapling and chirped his song, remaining for a few minutes before flying to the trees towards the end of the trail. A few more White-breasted Nuthatches were sighted in the forest along the field. We were able to see three more Hairy Woodpeckers on this portion of the trail, and three additional Downy Woodpeckers. As we were making our way across the road, our attention was diverted by the raucous cawing of five American Crows. We soon learned the cause of their alarm when they flushed a Red-tailed Hawk from its perch and drove it to a tree branch directly above us. They landed in the tree with the hawk and continued to “yell” at it. We observed for several minutes before heading back to the car, seeing one more American Crow joining the flock before ending our very successful excursion at 11:07am.
Social Behavior and Phenology
The Mallards that we observed in flocks in the water were composed of males and females. In the first group, there was a male and two females wading farther away from the larger group. When another male approached, the first male began quacking loudly and flapped his wings vigorously. The other male quietly retreated away from the three others in response. This combination of audio and visual display was clearly meant as a warning to the other male not to approach his females. Another brief aggressive display took place on the portion of the trail near the field between two Downy Woodpeckers. One individual was on a relatively large tree and the other was close by but on a separate tree. When the second woodpecker flew to the other occupied tree, it landed quite close to the first bird. This bird responded by fluffing out the bright red cap on its head and fluttering towards the newcomer, to which it responded by quickly retreating across the trail to another patch of forest. This visual display served as a warning that the bird was not willing to share its space. A final aggressive display took place between two different species, when five American Crows flushed a Red-tailed Hawk to a different tree. They surrounded the hawk when it landed and cawed loudly and continuously, clearly displeased with its presence and “encouraging” it to leave. The hawk was fluffed out, perhaps attempting to look larger and dissuade any more provocation, though it did not cry out or flap its wings while we were watching it.
One of the species we observed was a male Northern Cardinal, its bright red plumage visible even through the dense bush it was perched in. Another equally bright species was a male American Goldfinch. The bright red of the Cardinal and the vibrant gold of the Goldfinch are both factors in attracting attention from potential mates. However, while the Northern Cardinal retains its vibrancy throughout winter, the American Goldfinch develops a drabber winter plumage. Although the darker coat makes the American Goldfinch less conspicuous to predators, the Northern Cardinal is visible to potential mates year-round, and this is advantageous for their sometimes-early breeding season of February.
One of the Canada Geese that we observed was resting on the bank along the river. This fits into the context of its circannual rhythm of migration, as the flight these birds must make requires periods of rest to maintain the energy they will need to complete the journey.
Pishing Mini Activity
There are a few different theories as to why pishing works to attract small birds such as Black-capped Chickadees. One idea is that the whispering noise resembles a bird that is anxious, prompting other birds to survey the potential threat and investigate the individual in trouble. It is also possible that the pishing noise resembles the alarm call of a squirrel, and small birds fly in to investigate the source of the disturbance.
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