Field Observation 1: ID and Flight Physiology

I began my bird walk in Winooski on February 17th, 2019, around 3:30 PM. It was a bright, sunny, and very cold (-7 °C) afternoon with light winds. At the entry of the Casavant Natural Area, I saw a group of Canada Geese and Mallards flocked on the frozen Winooski River, some bathing in the frigid water while others stayed on the ice. As I continued my walk along the river, a small flock of American Crows flew overhead. Their flight style was a mix of smooth wingbeats and occasional, short gliding. They seemed like they were capable of flying for a while, easily traveling into and out of my field of view without touching down. Shortly after, a small songbird that I was unable to identify flew a short distance between trees. This bird had an undulating flight style, dipping and rising before landing on a branch and taking off again, flapping its wings in a a blur. Although I'm not certain what species of bird this was, I can say for sure it wasn't a sparrow or a wren, since they typically fly in a straight and level path. On the other hand, it may have been a woodpecker or a finch, who utilize a "bouncing" flight style.

There are many differences between a small songbird and a crow- it is improbable to visually mistake one for the other. I would not really need to examine their flight styles to tell them apart. However, if I were trying to tell the difference between a crow and a raven in flight, I would need to pay special attention to variations in flight style. For example, the crow has a fan shaped tail in flight, while the raven has a more round looking tail- this would a key identifier for telling the two apart. Ravens also flap less than crows do, and tend to soar/glide for longer periods of time. Flight styles can be very revealing identifiers between two visually similar species.

Small songbirds and crows occupy different environmental niches, which can be somewhat interpreted from their flight styles. Crows are scavengers, eating pretty much anything they come upon. A songbird's diet usually consists of seeds, fruits, and/or insects. Their diet doesn't typically require them to look for food from above, whether it be mice, roadkill, or garbage scraps- they can hop from tree to tree, and usually find what they're looking for. Perhaps differences in diet have contributed to the drastically different flight styles between a crow and the songbird I observed. While the crow scavenges for food from its vantage point above, the songbird flits through the forest and doesn't have to sustain flight for too long before it reaches the next tree over, where it is likely to find an insect or some berries.

Publicado el febrero 17, 2019 11:54 TARDE por jessharkness2