Field Observation 3 - Social behavior and Phenology

Date: March 17, 2019
Location: Salmon Hole (44.4870° N, 73.1881° W)
Weather: about 27 degrees F, mostly cloudy, fresh layer of about half an inch of snow
Habitat: mixed hardwood trees (some maple, birch, cottonwood)
Other: some of the trees have started budding, lots of snow/ice melt occurring, ice that was covering certain sections of the river is breaking up
Arrived: 9:47 am
Departed: 11:38 am

This birding outing was the most successful one I’ve gone on so far this semester. I went earlier in the day than my prior visits and the birds seemed much more active. In addition, since the weather has been getting warmer the past few days, there were more species around. Some migrants might also be back or returning within the next couple of weeks and will be exciting to see! This time I recorded a total of seven different species including the following:
• American Crow - Observed dozens at the far bank of the Winooski River by the dam and heard them calling
• Mallard - Observed at least a dozen floating down the river and heard them calling
• Herring Gulls and Ring-billed Gulls - Observed a large group, probably over 50, gathered in one section along the river and heard them calling
• Common Goldeneye - Saw one male foraging in the middle of the river
• Hooded Merganser - Saw one male and one female foraging in the middle of the river
• White-breasted Nuthatch - Heard one calling
• Tufted Titmouse - Heard one calling

There were many species gather within a fairly small area, mostly within a few hundred feet of one another or closer. This means they were all interacting with one another by sharing the same space. The Mallards, Mergansers, and Goldeneye were all foraging in the same area and didn’t seem to be expressing any antagonistic behavior. They all remained spaced out from one another. The Mallards were calling back and forth to one another, but I didn’t hear the other calling. The Herring and Ring-billed Gulls were all gathered in the same area with very little space between one another and were all calling loudly to one another. Maybe they were trying to adjust their spacing or communicate about the foraging. A few individuals at a time would fly out from the group and soar over the river and then return to the group. There was a large group of American Crows past the group of gulls and they were cawing loudly to one another as well. Occasionally some would fly from the river bank to the opposite site of woods, then return. None of the calls sounded particularly alarmed so the communication was probably mostly social or informational for other members of its species.

The American Crow is a very darkly colored species in comparison to Herring Gulls or Ring-billed Gulls. This allows them to absorb more light and generate heat. Against a light sky, the black coloration stands out, but in the evening or with the cover of trees, it can work as camouflage by resembling a dark shadow in the canopy. The Gulls are much lighter overall in coloration. The adults of both species are typically light gray on the back and wings, with the tips of the wings being black. The underside and head are white, which can be beneficial when foraging because the prey below looking up at a light sky and white underside are less likely to see them.

The single bird I focused on for about ten minutes was the Common Goldeneye. This species often forages in groups, but this male was by itself. He was floating in the middle of the Winooski River and every so often would dive forward and resurface a few seconds later. I didn’t see him come up with anything in his beak after any of the dives, but he could have already eaten the prey as he was resurfacing or was just not having success in hunting. This species is diurnal and therefore is most active during the day. It was around ten in the morning when I saw this one foraging.

Posted on March 19, 2019 07:27 PM by mwolpert