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Date - 5/10/2021
Time start - 7:50am
Time end - 8:20am
Temperature - ~55 deg F
Started out ~90% cloud cover, turned into 50% cloud cover after about half an hour
Wind ~5mph S
Habitat was a very open area among many residential structures, and very wooded areas on the outskirts. Stopped by a small pond area near Redstone Lofts with a lot of vegetation as well.

Date: 5/9/2021
Time Start: 9:00am
Time End: 11:00am
Temp: 50 deg F
Weather: 90% cloud cover
Wind 15mph NW
Location: Landy Park, Winooski
Habitat was very open and grassy amongst man-made recreational structures, and also in lightly wooded areas with hiking trails sandwiched between houses.

Date - 4/24/21
Start Time - 9:05am
End Time - 10:30
Location - University of Vermont Redstone Campus
Temperature - 54 deg F
Wind 10mph S/SE
~100% cloud cover
Zero precipitation
Habitat was mostly very suburban, with numerous buildings populating open, grassy areas, and sparse trees. Spent some time around a swampy-pond area within the residential areas.

The main behaviors related to territory/nest/mate selection were defensive strategies against other birds both of the same and different species. An American Crow chased a Red-tailed Hawk between the trees to defend its territory. Two male American Robins stood near each other outside one of the Redstone dorms, either getting ready to fight or having just gotten out of one and probably trying to defend nesting territory and/or mates. These interactions took place near trees and shrubs next to tall buildings - aka places that nests likely reside. Crows typically build their nests in tree crotches or on branches, while Robins make their nests among shrubby bushes and conifers and can be found in residential areas! Generally, early nesting birds like the Robin as well as Northern Cardinals and Chipping Sparrows use conifers and shrubs as their nesting sites to gain the most cover, and which are also near sources of food like seeds and fruit. As demonstrated, Robins can be very territorial, and they only make about one nest per bush. Other species similarly need cover when choosing their nesting sites, and which must be closer to their own respective sources of food. Red-winged Blackbirds build their nests 1-1.5ft above areas of water amongst dense vegetation like cattails - close to the water surface so they can feed on insects, frogs, and snails, with no real need to go out to the trees. Similarly, Canada Geese make their nests right near the water in order to feed on fish, insects, and the vegetation on the banks.
We found a Red-bellied Woodpecker singing very loudly on a tall tree right outside of a house. It was the only one of its species there. In one sense it might not be defending very good territory, because there are not as many sources of food around the house as there might be within woods (there was really only one or two trees on the property). Depending on the species, human interference might also pose a real survival problem. Additionally, the lack of other birds around the property could be a sign that the territory is not the most desired and fruitful. However, in another sense the house and other materials on the property might provide plenty of cover for the Woodpecker, and the tall tree the Woodpecker was on might itself be enough of a source of food and cover just for that bird. Some people may also have bird-feeders on their property as well. Furthermore, perhaps human presence is a good deterrent to rival species of birds that are not as well-adapted to human activities. Overall I’d say the Red-bellied Woodpecker seemed pretty well off for itself and was defending fairly good territory compared to other members of its species, indicating that that bird had high fitness compared to those other members as well.
The main nests that we observed were the nests of American Robins, made of dead twigs, grasses, hairs, and even some mud and dirt. The bottoms were very solid. Generally, the coarser materials were on the outside of the nest while the finer, more valuable materials made up the center, making it easy for the birds to rebuild their nests if the outside was destroyed. The bird would have to carefully scout the ground for twigs, grasses, and hairs. Much of their materials would probably be concentrated on the ground around forests, near trees and vegetation. Most of the nests we saw were also made in the center of shrubs where most of the deader branches reside, making it quite easy for birds to acquire those materials in the same spot they intend to make their nests! Some of the materials like hairs might also be found closer to residential areas rather than forests, and of course, human-planted shrubs and trees also conveniently exist on those properties as well.

Date 4/17
Start Time - 1:11 pm
End Time - 2:45
Temp - 45 degrees Fahrenheit
Wind - ~20mph NE
100% cloud cover at the start - 65% cloud cover after around half an hour
Location - Redstone Campus and Downtown Burlington
Habitat was primarily open within a built environment, populated by buildings and telephone wires among the open streets and grassy areas. Some sparse trees populated the environment along streets as well. The habitat had heavy human habitation and influence, with many people constantly present either walking or from vehicles, and many of the "natural" areas human-made.

Date - 4/3/21
Start Time - 9:08am
End Time - 10:33
Location - University of Vermont Redstone Campus and Burlington Country Club
Temperature - 30 deg F
Wind 20mph NW
~100% clear
Zero precipitation
Habitats were open, grassy grounds of the Gutterson field, the swampy-pond area near the Redstone Lofts, and up past the Redstone Commons to walk the path at the Burlington Country Club. Many birds individually and in groups flitted between trees and glided on the clear air, almost in a leisurely way. The areas where we observed them were very open, leaving a clear view of their perches on fences, vegetation, and trees.

Some of the year-round species we observed were the House Finch, Black-capped Chickadee, Common Raven, Rock Pigeon, and Ring-billed Gulls, who overwinter in the Northeast and don’t need to travel far to adjust to the colder temperatures and changed food availability. Their diets primarily consist of invertebrates (e.g. worms), seeds, and fruits that still exist during the winter months. Their bills are short, stubby and even conical (like the House Finches), to better adapt to cracking open and eating seeds. In a similar vein, Gulls have a primarily piscivorous diet allowing them to hunt fish in Lake Champlain during the winter as they can in the summer.

Facultative migrants we came across were the American Robin and the House and Song Sparrows. On average the straight line distance these species travel from their wintering grounds to Burlington is ~1000-2000mi. Their migration is dependent upon the food availability of the year, and if they do decide to migrate they don’t go too far into the tropics, typically staying in the southern US range. Their diets are the most adaptable - omnivorous and generalist - often making them opportunist species. Facultative migrants can survive on the same diet as year-round species, able to take advantage of the fruits, seeds, and invertebrates available during the winter, or able to migrate down south and feed on insects if need be like the obligate migrants do. Sometimes, as with the American Robin, some members of a population stay in the Northeast during the winter while some of the population migrate because of the intraspecific competition occurring. When the more competitively advantageous population members start to feed, there is less food availability for the less competitively “fit” population members. Other times the limited food availability comes from the conditions of the year itself. The Song Sparrow is a species that we have only been starting to see on our field trips, most likely arriving from somewhere in the Southern US and coming into Burlington as the weather gets warmed and a higher variety of overall food is available, so they do not need to compete as hard to eat. This is in contrast with the American Robin, who we’ve been seeing since our first field trip and whom the majority of likely did not migrate during the winter, given the proliferation of fruit and seeds in the area.

Obligate migrants we saw were the Eastern Phoebe and Red-winged Blackbird, likely coming from tropical areas back to Burlington as the weather gets warmer. On average the straight line distance these species travel from their wintering grounds to Burlington is anywhere from ~2500-5000mi. These species are insectivores, and need to migrate down south due to the lack of insect availability in colder climates. Changing climatic conditions, however, complicates these natural circannual cycles of the different bird species. The timing of spring has been very erratic for the past few years in light of worldwide warming temperatures and anthropogenic disturbance. During some weeks the weather here is warm as though it’s on the verge of spring, and in the next week it snows. A huge disadvantage of these obligate migratory species arriving in early April is that it will continue to snow some weeks and give them a competitive disadvantage when searching for food in a climate they are not adapted to. Snow likely confuses their circannual cycles and causes a further energy deficit that was already spent from migrating back to the northeastern US. On the other hand, an potential advantage to this early arrival could be that early mating and reproduction offset this lack of initial food availability and give the birds a competitive advantage over other later arrivals for finding mates. Changing climatic conditions also makes the categories of migratory birds themselves very fluid. Tufted Titmice are omnivores but are generally non-migratory species, favoring a seed-based diet overall. However, recent changing seed availability has led them to appear further south in the US. Conversely, more and more facultative migrants are seen to be sticking around in the Northeastern US in recent years, likely due to the weather staying warmer for longer and reducing competition for those species.

Sources:
https://www.allaboutbirds.org/news/
https://journeynorth.org/tm/robin/facts_migration.html

Date - 3/20/21
Start Time - 9:40am
End Time - 11:05
Location - Burlington Waterfront Bike Path
Temperature - ~38 deg F
~100% clear

Many of the birds we saw on the lake seemed to be engaging in feather fluffing in an attempt to keep warm in the breezy, cold air on the still partially frozen lake. Most of the time they would sit still as if in an effort to conserve energy to keep warm, but every once in a while they would rise slightly out of the water and ruffle their feathers to trap air along their body for extra insulation. In particular, I saw a Common Goldeneye floating near both other birds on the water near the beginning of the bike path, sometimes swimming near enough to partake in a “social” huddling act, likely in order to keep warm as well. These thermoregulatory behaviors are all a part of the birds’ circadian rhythm, or intrinsic cycles birds engage in on a 24hr basis. We observed the birds during the day, when thermoregulation - as well as eating and metabolic activities - were high. The Common Goldeneye would fluff, huddle, and dive under the water to feed on fish and other lake invertebrates. We weren’t able to observe any of the birds at night, but most likely the bird would reduce its metabolic and thermoregulatory activities (decreasing body temperature decreases metabolic activities) and sleep out on the water, which incidentally naturally warms in comparison to the land during the night.

Conversely, both the Herring and Ring-billed Gulls we saw spent their time catching thermals around the land and gliding over it, very likely scouting out for fish to eat. A couple other species like the Canada Geese engaged in these gliding activities around the lake as well. Common Grackles were the other major species we saw, and they spent most of their time flocking together - sometimes with Red-winged Blackbirds - between trees and telephone poles. The trees likely provided a microhabitat to keep warm, as well as a source of food to take advantage of their higher metabolic capabilities during the day. I think it’s also likely that the trees and telephone polls are places they would sleep during the night time. All locations that each of the species chose to sleep would provide them with exposure to the changing daylight throughout the year, entraining their circadian rhythms. Most of the bird species on and around the lake did not directly interact with each other, especially given that winter is ending and the need to flock together is going away, but many of them behaved in similar ways in line with their circadian rhythms, sending out calls to members of the same species as if to alert them to potential prey (this was especially done by the species of Gull). The Common Grackles responded vocally to spishing while foraging in the trees as well, becoming very attentive to that kind of sound. Spishing could mean a lot of things to different birds, but the most likely hypothesis is that it sounds like small songbirds, namely the Black-capped Chickadee, and overall just gets the bird’s attention to some kind of call or song.

Back to the Common Goldeneye, while the birds were trying to keep warm or hunting for food, the Common Goldeneye was just starting to mate as a part of its circannual cycles. As a male, it would stick its heads up and down in a bobbing motion to attract female mates. Soon, as the weather gets warmer and food becomes more abundant, the bird will arrive at the breedings grounds with his mate, who will start to incubate their eggs by the summer solstice. Their diets might change towards more insect-based diets as they become more available in the summer, as simultaneously the migratory species come back to feed on these now present insects.

While the Common Goldeneyes had some white feathers on their sides, their plumage mainly consisted of iridescent greens and browns. By contrast, the Herring and Ring-billed Gulls have an advantage during egg incubation due to their white plumages, which reflect solar radiation and help their eggs not overheat. Gulls also spend a lot of their time in flight due to the gliding abilities their high aspect ratio wings allow them to have, giving them much exposure to solar radiation in the air and making it so their white reflective plumage doesn’t need to absorb the sunlight on its own. They are able to expose different body parts to the sun very easily. Conversely, when the Common Goldeneye is out of the water and exposed to the sun, their plumage is darker, likely needed to absorb solar radiation due to the less intense exposure from the water. Their side feathers are able to be white possibility because those spend a lot of time in water, away from the sun. When the time comes to get out of the water and incubate their eggs however, their whiter plumage closer to their bottom may potentially give them the same evolutionary advantage of preventing egg-overheating just like the Gulls, providing another advantage towards successfully completing their circannual cycle.

Ecological Physiology

Date - 3/6/2021
Start Time: 9:10am
End Time: 10:30am
Location: UVM Centennial Woods
Temperature: ~18 degrees Fahrenheit
Wind: 10mph West
~80% cloud cover

One of the main adaptations of birds to winter that we saw in our area of Centennial Woods was the mixed species flocking in the woods. Overall it seemed most birds were hiding away from us wherever their nesting sites were, likely resting and conserving energy in the face of the winter cold. The times when we did see birds were mainly to see them feeding. When we were walking down the trail at the start of the path there would be bursts of sound from multiple species of birds, which would then peter out. Many birds would flit between the trees quickly before flying away. It seems clear that all these birds are flocking towards a food source in the tree, and that travelling together would increase each individual’s chances of finding food without as much effort spent. The more diverse a travel group is, the higher competitive advantage one has over those who are only reliant on what they know themselves.
I think it’s also possible that these mixed species groups flocked in order to find nesting cavities. Throughout the trail there were many dead snags, especially on the edges closer to the residential area, which incidentally is where we heard the brunt of the mixed species calls. The snapgs have cavities punctures into their bark, many of them that were fairly small in accordance with the snag size. At the beginning of the path near the residential areas, the snags were a good deal smaller and shallower than those deeper in the forest. Deeper in the forest the cavities got more numerous and deeper on the taller snags, around the size of tennis balls. All of the cavities tended towards the top of the tree, giving credence to the fact that birds form them for nesting purposes during the winter as a form of thermoregulation to stay out of the cold. The majority of the mixed flock flitted among areas with larger snag size and more numerous, deeper cavities. It is possible birds abandon smaller snags as the tree continues to age and decay in favor of the taller, denser newer snags.
It is also extremely possible that insect-eating (e.g. the White and Red-breasted Nuthatches we observed) and wood pecking birds are the species that utilize cavities the most often, especially with wood pecking birds physically forming the cavities themselves. There is a huge lack of insects as a food source during the winter, so cavity formations are an adaptation to staying maximizing the scarcer source of food available. Other birds species take to finding fruiting trees in place of insects, especially the Red Crossbill. The highest abundance of fruiting trees (especially crabapple trees) during the winter appeared in residential areas as opposed to the deeper forest of Centennial Woods - and that was where upwards of twenty Red Crossbills flocked. Many birds on the trail also flocked towards areas where they likely could find seeds on the ground or in the trees.
A tell-tale sign of a winter adaptation that was slowly starting to evolve back was the prevalence of the Black-capped Chickadee’s song over its call. Every once in a while we’d get a “chicka-dee-dee-dee,” but the “hey sweetie” was consistent. This was a sign that while the majority of birds were resting or feeding, slowly some species were starting to transition into their spring/summer behaviors. The Black-capped Chickadee was sending out its mating song more often than its normal call. Eventually, the mixed species flock that we came across will separate, with individual species going back to finding food and shelter and focusing their energies on breeding when the summer months come.

ID Flight and Physiology

Date - 2/21/2021
Start Time - 9:09am
End Time - 10:40am
Location - UVM Redstone Campus, South Prospect Street
Temperature - 23 degrees F
Wind Direction - N/NW direction
100% sun

We saw a handful of Herring Gulls (I myself saw around 4) and potentially some Ring-billed Gulls circling around the area between the Interfaith Center and Redstone Hall, having apparently caught a thermal and gliding in a circle up above. The Herring Gulls had black streaking on their head in line with their prebasic molt taking place, and they had distinct long, high aspect ratio wing-types. As they glided in a circle above us, they flapped their wings only ever so often, spending most of the time just gliding in a fairly relaxed manner. Their high aspect ratio wings clearly are giving them a lot of lift and making it so that they didn’t need to use up a lot of energy. It was a little surprising to find them a little ways away from Lake Champlain, especially on the walking path leading to Redstone, but it made sense given their long wing length, which would result in a lot of lift and take the Herring Gulls easily to and from place-to-place with little effort. Even if their habitat niche is around bodies of water, their wing-type makes travelling long-distances very simple for them.
This is in contrast to both the American Crow and the American Robin species that we saw, which both seemed to have some cross between an elliptical and high-speed wing-type. The American Crow definitely erred more on the side of an elliptical wing-type with its splayed, broad feather tips, but through the binoculars I could see it flapping very rapidly and regularly in the vein of a high-speed wing-type. As Allan said, crows are generalists! They fly in both open areas and through forests, making their broad-tipped elliptical wings helpful for a variety of terrains. And they also fly long-distances to get to these areas, making the more sharp relief of their wings less long and apt for gliding and more dynamic for high-speed travel. American Robins also flapped very rapidly to and from their various perches on the Redstone Green, rarely ever gliding. I would hazard a guess that they are also generalists, getting food from multiple areas both open and forested just like the American Crow.
Maybe I’m a bit of a novice, but we saw a lot more birds than I thought we would in the cold. We saw a lot on the Redstone Green where there was a crabapple tree feeding around 8-9 American Robins, and easily around 30+ birds in a residential road just off of South Prospect Street where there were multiple bird feeders. The majority of species we saw in the residential area were Common Redpolls, though there were ~5 Mourning Doves and at least 1 male White-breasted Nuthatch. We found a lot of the birds perched on various buildings around the Redstone Green, probably trying to get some of the sunlight that was shining down on us, and also because it was probably near some of their nesting areas (like the two Rock Pigeons we found tucked into a corner of Redstone Hall)! I think there’s definitely the perception (at least that I had) that there are barely any birds in the winter because they migrate, but obviously many birds stick around during the winter months without any problem, likely adapting to the change in season by molting into their winter plumage (like the Herring Gulls’ black streaking on their heads). We found the most birds where there were areas of food, and where there was a tall building or tree to perch on.