Social Behavior and Phenology

Locations: 89 North (the highway Boston-Burlington) and outside Harris Millis Dining Hall University of Vermont Burlington VT on 3/25/18
Weather: overcast, cloudy. Little to no wind.
Time: Cooper's was around 6am, at UVM around 10/11am
I looked for birds around campus at UVM, and on my ride from Boston to Burlington. On the ride, I saw a Cooper’s Hawk and five crows. I was very upset that I couldn’t get my phone out fast enough to catch a picture of the hawk, and then the car was moving too fast to get one of the crows. The crows cawed to each other and would fly towards and away from each other. I was unable to observe them for more than a moment or two unless the individuals flew alongside the car. Once back on campus, I observed two American Robins foraging in the little section of grass outside of the Harris Millis Dining Hall. The Robins were interacting by chirping to each other, and hoping around in and out of each other’s spaces while foraging. I am not sure what visual clues the robins may have been employing, but I believe that the moving in and out of each other’s personal space may have been signals for the others to move or to try to steal the land. They may have been trying to tell each other of good spaces for foraging or to move out.
The male robins had bright rust colored chests and grayish backs and yellow beaks. The Cooper’s Hawk, had a yellowish beige striped front and a dark grayish back. It was surveying the strip of grass between the highway and the forest, waiting for prey to walk by, while the American Robins were actively foraging along the grass and snow. The robins’ coloration was not intended to hide them from predators nor from prey. They simply look pretty for no other advantage besides mating. Cooper’s Hawk’s coloration was due to having to blend in a little bit to the forest so that its prey wouldn’t spot it and run/hide. The robins foraging fit in with the time of year. They were looking for plant materials to eat, versus in the spring or when there is a thaw when they would eat worms and insects. Since it was also midmorning, it made sense that they would be looking for food. If they had been looking for food at dusk, it would have been unusual, and it would also be unusual to see them sleeping at this time of day.
The phishing sound may be appealing to small birds for a couple of reasons. It may remind them of an insect crawling through dry leaves, and make them interested in you as a potential source of food. The phishing may just be an interesting sound to them. So they crowd around. It may also sound like a warning call, so they crowd to try to find the source of the danger. I have also found that making a mourning dove call or variations of it by blowing into my closed hands tends to attract the attention of smaller birds. I’m not sure why, but maybe it is for a similar reason to the phishing.

Publicado el 27 de marzo de 2018 por esm398