Käyttäjän lenarose16 päiväkirja

Date - 3/6/21
Start time - 9 am
End time - 10:30 am
Location - UVM Campus and Centennial Forest
Weather (temperature, wind speed/direction, precipitation) - 16 degrees Fahrenheit, 10 mph wind, ~80% cloud cover, no precipitation.
Habitat(s) - Residential area with occasional pine and crabapple trees; Mixed deciduous and evergreen natural area with a brook running through.

We walked from Aiken down into Centennial Woods. Birds were only present sparsely in open habitats on campus, and were most usually seen foraging in denser vegetation, which could potentially be a behavioral strategy by which they can be sheltered from the cold by vegetation and retain body heat. Birds seen outside of the woods were most often seen foraging on fruits from ornamental crabapples or seeds from pinecones; for birds wintering in the northern woods, insects are absent and fruits and seeds must be the primary food source. The barred owl and juncos in particular seemed to associate with dense evergreen areas. Many of our sightings were part of a single mixed-species flock, including two species of nuthatch, brown creepers, and chickadees. Mixed-species flocks are likely a behavioral adaptation to winter conditions, allowing birds to forage efficiently and pool knowledge of food resources, avoiding energy waste associated with searching alone. Some signs of spring could be seen: Black-capped Chickadees have begun singing, and crows when seen were foraging singly rather than as parts of large groups.

I observed a number of snags, usually in areas where birds were also abundant; for example on the periphery between a residential area with crabapple trees and Centennial Woods. One cavity hole had droppings in the opening, indicating that it was in use by birds. Nothing appeared when the snag was rapped on. Snags shelter birds from the cold and are primarily used overnight by small northern wintering species, including Black-capped Chickadees and woodpeckers. Many of the holes in the snags had limited space inside for a bird to roost; deeper cavities were more rare.

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.