Field Obs2: Physiology

Kyler Mose
WFB130: Ornithology
Field Observation #2: Physiology

Date: 05-March-2019
Time: 8:30-10:30AM
Location: Ethan Allen Homestead, Burlington, VT
Coordinates: 44.5082, -73.2295
Weather: Sunny, partly cloudy, 18°F (-8°C)
Habitat: Mixed (see first paragraph below)

I went birding in Ethan Allen Homestead Park which was a mixed habitat of coniferous and deciduous trees along with open fields and swamp lands. This New England forest was cold, but the birds have adapted to survive these cold and resource-limited winters. To compensate for the high metabolic needs to stay warm in winter, these winter residents must have a high caloric intake. Many birds, like the Black-capped Chickadee observed, bulk up in the Fall when food resources are more available. But they are also intelligent birds and can remember where major food sources are, like bird feeders or trees with high seed densities. This can be observed in Black-capped Chickadee aggregations near trees with higher food output.

Birds also have behavioral and morphological responses to survive the harsh winters of New England. They can be seen huddling, which was not actively observed in this outing, but puffing of feathers can be readily observed in most winter birds. The Northern Cardinals observed all had fluffed feathers in order to warm air in their down feathers to increase insulation. Black-capped Chickadees are another common bird that can also be seen with puffed feathers to aid in insulation. Birds are also able to enter a state of torpor, or a regulated hypothermia, where they drop their temperatures up to 15°F at night, which allows for many energy conservations during cold nights.

Dead trees can also prove useful as habitats for birds to shelter themselves from cold nights. Many of the dead snags passed along the field observation were upright and in initial stages of death. There were large hallows in many of the snags, which could prove helpful in protection against cold nights. No strong correlation was found between snag density and bird density, but the area surveyed was not great, so short foraging trips away from a night time shelter is a possible explanation. No great energy is expended to travel from a nigh shelter to a food-dense region within the same forest.

Posted on March 5, 2019 10:11 PM by kylermose