Archivos de Diario para febrero 2018

viernes, 16 de febrero de 2018

ID and Flight Physiology

Field Observation #1
10:00 – 11:45am on Sunday, February 11, 2018
Weather: Overcast, 27oF with periodic light bursts of freezing rain. Six inches of snow on the ground.
Location: Charlotte Town Beach, Charlotte, VT
Habitat: Small harbor, a corn field, and a small park that was backed up against a mixed deciduous and coniferous forest. Major tree and bush species included shagbark hickory, northern white-cedar, staghorn sumac, white ash, and eastern cottonwood.

After parking, my friend and I meandered towards the waterfront to look for two Harlequin Ducks that had been sighted several times over the last few days. Immediately after getting out of the car, we were met with a group of 28 American Robins, browsing on the grapevines that covered a few trees. We heard several Black-capped Chickadees chattering to each other, along with a pair of Tufted Titmice. Off in the distance, a Common Raven gurgled as a group of around 15 Cedar Waxwings zipped overhead. The morning was off to a solid start.

Nearing the water, we identified four Common Mergansers, 100 Common Goldeneyes, and three Ring-billed Gulls. Sadly, there was no sign of the Harlequins. We then walked up the road and around the field and saw a Common Raven, two American Crows, a Tufted Titmouse, six Black-capped Chickadees, a Rough-legged Hawk, four Downy and three Hairy Woodpeckers, two American Robins, and four White-breasted Nuthatches.

As the Downy Woodpeckers foraged from tree to tree, I observed their flight pattern and shape. Downy Woodpeckers have an undulating flight pattern, where they beat their wings a few times then drop for a few seconds before beginning to flap again. This flight pattern, which resembles a sign curve, is characteristic of woodpeckers. Downy Woodpeckers have very shallow dips as they fly, which can be used to set them apart from other woodpeckers, along with the small beak to head ratio. Their wings are short and rounded, with a low aspect ratio. This allows them to take off quickly and maneuver easily through the thickly vegetated forest where they forage. Short, round wings are not good for flying long distances, but since Downy Woodpeckers are resident species, this is not an issue.

After initially landing on the bole of a tree, the Downy Woodpecker (in this case a male) began picking his way up the tree, stopping to forage every few hops. Once the little guy got up to a choice branch, he picked his way out onto the thinner twigs and continued to forage for a while. He then fluttered or hopped to a branch of the next tree and continued this pattern for five to 10 minutes, finally taking off and flying to another tree across the thicket, bouncing his way through the air.

I compared the Downy Woodpecker’s flight to that of the Common Goldeneye. While we were at the waterfront, several pairs of Common Goldeneyes came and went. Their wing shape is short and pointed, giving them a lot of thrust and allowing them to fly rapidly. The medium-high aspect ratio and relatively low maneuverability of their wings is helpful for migration and a life history in relatively open habitat. When flying, Common Goldeneyes must flap quickly and continuously, making their flight pattern very even (in contrast to the undulations of the Downy Woodpecker) but seemingly more laborious. They are rather noisy fliers as well, making whistling noises as they flap.

Before we left, we returned to the waterfront. We noticed an elderly gentleman with a scope and walked up to say hello, asking if he had spotted the Harlequin Duck. He said yes, and offered us a peek. Only the male was there, and the man proceeded to tell us that two Bald Eagles had been seen bothering the pair and the female had not been seen for a few days. I am afraid that she may have become dinner. He also showed us said Bald Eagles, who were standing on the ice, and pointed out a Red-breasted Merganser. This concluded our day, which was very fulfilling overall.

Publicado el viernes, 16 de febrero de 2018 a las 02:27 AM por jpupko jpupko | 16 observaciones | 0 comentarios | Deja un comentario