Diario de emerrylees

Today I went for a bird walk starting at 4:09 pm and ending at 5:42 pm. I was out for about an hour and a half. My last walk I went during the middle of the day, so I went later in the afternoon this time to see if it would impact the number of birds I saw. Today was warm at around 40 degrees Fahrenheit. When I started the walk it was sunny, but it got progressively more overcast and dark as the sun started to set. The temperature also fell a little bit during this time. There was a slight wind coming from the northwest at 10 MPH. I started my walk in the Redstone Campus at UVM. There are many buildings and people here, and some would classify this as an urban location. I then walked onto the paved path that parallels the track, and from there moved to the golf course. The golf course provides a variety of habitats, from open to stand alone trees, to more forested areas.

While on Redstone I moved towards Simpson Hall because I often see birds here when I walk to class. The seagulls were all over the place and calling to each other. I sat next to some of the shrubs that are located along Christie Hall. Here is where I noticed the chirping of the House Sparrows. Some flitted out of the shrubs and into some nearby trees. I also watched the European Starlings up in the trees. They were clicking. I decided that I wanted to head to some more forested area, so I made my way through the Redstone campus and onto the golf course. At first I had trouble locating any birds, but after remaining still for a bit I began to hear some song. I followed the song until I encountered a White-breasted Nuthatch perched high in a deciduous tree. I continues to listen for birds, and follow my ear to them. This was an effective strategy. I made my way through much of the golf course, jumping between the more forested patches as I wasn't finding any birds in the open grassy fields.

Today was a fairly warm day, so maintaining body temperature was likely not as much of an issue for many birds. However, I did notice that the House Sparrows were perched within a shrub. The shrub could be acting as protection from wind. This is a behavior utilized by birds to maintain body temperature. The European Starlings and House Sparrows were spending most of their time simply perched in their trees, resting, suggesting that they are trying to reduce their energy output so that they can allocate this to maintaining their body temperature. Also, they could have done their foraging earlier in the day and were settling down for the night (the sunlight had an orange glow that suggests the sun was soon to go down and night was approaching). Contrastingly, the Ring-billed gulls, White-breasted Nuthatches, Black-capped Chickadees, and American Crows were often in flight. I noticed in particular that the White-breasted Nuthatches spent a lot of time foraging. Perhaps since it was a warmer day, they had to allocate less energy to staying warm and could therefore spend more time feeding/foraging. They were tapping at the bark which was surprising. I assume they were foraging for insects or seeds, but I would not expect many insects to be out yet. I would have expected to see them in some of the trees that still bear fruit, as was the case with the House Sparrows. I would think to find most of these species roosted in trees further away from human reach or within the shrubs. However, on the edges of Redstone campus, they would be at less risk of human influence, but perhaps protected from predators who do not want to approach the highly human-influenced setting.

I did see a number of snags, but I did not notice any birds utilizing these snags. However, in the bigger snags there were larger cavities which could be associated with greater bird abundance. If the birds utilized huddling to maintain body temperature during the cold nights, more birds would be able to fit into a large cavity, resulting in higher abundance here during nightfall as they find their places to roost. Snags are important because they provide protection from the elements and ground predators. I would expect to find birds that cannot go into torpor or controlled hypothermia in here as a way to maintain their body heat and huddle with others. Small birds may be more likely to use them because they have a higher surface area to volume ratio, meaning that it is easier for them to lose heat to the environment.

I went for a bird walk while visiting the Ding Darling National Wildlife Refuge on Sanibel Island, Florida. This walk took place on Tuesday, March 10. The walk began at 11:30 in the morning and lasted until about 2:10. It was a beautifully sunny day with a few scattered clouds. There was a significant breeze coming from the south with gusts up to 20 mph. It was humid at warm at 80 degrees Fahrenheit. The Wildlife Refuge is interesting because it strives to make it so people of all different capabilities can get out into nature to see the amazing wildlife that lives in Florida. That being said, the refuge extends well beyond the area accessible to people. They have built a path that tours through a fairly small section of the refuge. This path is accessible by car, on bikes, or on foot. However, you are not allowed to stray beyond the path as to preserve the habitat quality for all of the organisms. As a result, I was not allowed to follow bird calls as I may have in a different scenario. Given the presence of many humans around me, it was more difficult to have those close encounters with the birds. It made observing subtle behaviors difficult. To add, many of the birds were removed from the people and out on the water.

The walk began in a relatively forested area. This then thinned and we passed over some bridges. From either side of the bridge you could look out. There were dozens of birds. In general they clumped into groups of the same species, but some of the smaller birds that you often see one beaches were in mixed groups. The path switched from thick vegetation to open water fairly frequently. This caters to many different species. Not only is there easy access to water and food, there are many places to hide and nest within the thick vegetation. This would not a suitable place for species that are edge sensitive because there are so many small patches with a high ratio of edge to interior areas. However, the closeness of the patchers allows for possible easy connectivity unless water is a barrier for a species.

The birds were not interacting to a huge degree, but there definitely were some interactions going on. The smaller birds within the mixed colony were very vocal. In general, they had high pitched calls. This makes sense given the habitats that they live in. The high pitch travels far across the open spaces associated with beaches and water. This colony actually flew in and landed on a sandy beach. They began feeding and preening. The vocalizations appeared to be communicating the idea that they didn't want to share their food with the other individuals around them. They often all ran in similar directions while foraging. The calls seemed a bit aggressive at times. It was hard to tell from a distance, but it could have been that the dominant males were using this to warn the subordinates that this is their space or their food. Similarly, the subordinates could have been acknowledging this, or communicating that they just wanted a little taste.

The American White Pelicans were amazing birds to observe. They had pure white plumage except for their remiges along the edge of their wings. Given the hot and sunny conditions this is evolutionarily advantageous because the white feathers absorb less heat, preventing the bird from overheating. The melanin providing the black color in the remiges provides increased rigidity and structure which helps maintain the feathers during flight. Additionally, given the abrasive environment in which these pelicans live, the melanins in these feathers give the feathers strength to resist wear from the surroundings. Alternatively, the Double-crested Cormorants have entirely black plumages. This seems counterintuitive given the sunny and warm conditions. However, they are a diving bird. They dive below the water to hunt. In order to remain submerged, they put minimal preening substances on their feathers. As a result, their feathers become saturated with water and the bird does not easily float. Once the bird is done hunting, they dry their feathers. Black feathers absorb the heat from the sun better than white feathers. This likely enables the to dry faster, giving the cormorant the ability to fly once more. The less time they spend drying their feathers, the less time they have to worry about ground predators. I did watch one willet for awhile. This willet was very restless and was eating a lot. This could be migratory restlessness, as many birds are now starting to a) migrate back north to their breeding grounds, and b) fill their fat stores so they will be prepared for migration. These behaviors are associated with increasing day length (correlated with circannual rhythms).

Lastly, I attempted the Spishing activity, but there were too many people around. I have done it on other walk though and have seen the affects. Possibly this could be intriguing to small birds because it sounds similar to, for example, a starling vocalization. They may want to see who this intruder or new neighbor is. This could be enticing to small birds because it could be part of their vocal repertoire.