UVM Ornithology Field Journal 4: Social Behavior and Phenology

Date - 3/21/21
Start time - 4 pm
End time - 5:30 pm
Location - West Spring St. and surrounding areas, Winooski
Weather (temperature, wind speed/direction, precipitation) - 62 degrees Fahrenheit, 1 mph wind, 5% cloud cover, no precipitation.
Habitat(s) - Residential/suburban area with sparse trees/little vegetation.

I noticed a number of birds beginning to transition to summer behaviors. A pair of male Northern Cardinals in red alternate plumage were chasing eachother around , flying after each other and emitting high pitched short squeaks as they did so; it at first seemed aggressive but they did not actually attack each other, so I wonder if I was seeing the beginning of territorial behavior, which would be fitting with their circannual rhythm. I heard many Northern Cardinals singing, and overall preparing for the breeding season. A number of other clues to the coming of spring: I saw an American Crow collecting sticks, presumably for nesting materal; it cawed loudly five times, then flew off with the sticks in its bill. I saw a pair of Mourning Doves cooing at each other, perhaps a courtship behavior. And I heard an American Robin singing. Ring-billed Gulls were prominent where I am, flying around in packs of 5 or so and loudly vocalizing to indicate when a food source had been located; they used auditory cues to maintain group cohesion as they foraged together. Moving inland and foraging in groups seems to be a seasonal mini-migration and change in behavior in gulls.

Ring-billed gulls have predominantly white plumage, perhaps making it more difficult for prey to spot them when looking up from below while the birds are hunting. Comparing them to another species with little sexual dimorphism, American Crows have all black plumage with some iridescence. The iridescence may be sexually selected, and I wonder if the black plumage is an adaptation for reducing parasite loads on the feathers and keeping cool by having the feathers heated up, diverting heat from the skin and creating an environment inhospitable to parasites. This may be especially important for scavengers like ravens.

My spishing attempts were not super successful! I located one Black-capped Chickadee, who was responsive and came to lower branches to investigate, but other birds did not seem interested. Perhaps spishing sounds like the scolding/threat alert calls of some birds, and birds are inclined to investigate, or maybe it just piques their curiosity. It seems to most effectively attract small bird species that would be inclined to mob a predator together, which would make sense.

Julkaistu maaliskuu 22, 2021 01:47 IP. käyttäjältä lenarose16