Archivos de diario de marzo 2019

08 de marzo de 2019

Winter Bird Physiology

Chickadees are wonderfully cold adapted and can drop their body temperature quite a lot through regulated hypothermia during the night. They spend most of the day foraging for food to keep their high metabolism satisfied and to gain enough calories to be able to burn throughout a cold night. Most often they go for foods high in fat content but will ravenously eat just about anything during winter months. Since they are expending much more energy during winter months in comparison to summer they need to maintain a high caloric intake and as such diets shift.
Bird feet contain very little soft tissue and thus can be kept quite cold in relation to the rest of their body. The warm blood from their body keeps their feet just above the temperature of getting frostbitten. This system is called counter-current heat exchange. Birds also fluff their feathers to trap air in between them which warms the air and thus warms the bird too. Birds may also gather together in roosts, such as the crows of downtown Burlington to huddle together for warmth during the night.
In Red Rocks Park where I observed a peregrine falcon, some chickadees, and heard a pileated woodpecker many species may overnight in dense thickets far from the water. This ensures that the birds are far from the cold winds coming off the lake at night. Some species may nest in cavities as well to stay warm.
There were a decent amount of snags at Red Rocks and cavities within them. Many large pileated woodpecker created holes that an eastern screech owl might inhabit, as well as some smaller holes perhaps created by other species such as northern flicker. Snags provide many homes for numerous birds and other wildlife. Tree swallows and wood ducks utilize them during the spring breeding season and mammals such as squirrels or raccoons may also inhabit them.

Ingresado el 08 de marzo de 2019 por michaelmcg michaelmcg | 2 observaciones | 0 comentarios | Deja un comentario

25 de marzo de 2019

Social Behavior and Phenology

Observations for this field journal were between 5:00 and 7:00pm at Woodside Park. I had the chance to observe a flock of crows which are incredibly social species and quite interesting to watch. They constantly do their “caw-caw” call to communicate with one another. They feed together in groups and have individuals looking out for any threats. They will sound an alarm if anything spooks them and then they all will fly away in unison. Individual crows also may fly around and scout areas for potential food and notify the flock that they have found something.

I also observed a red winged blackbird and a few white-breasted nuthatches. Red winged blackbirds have distinct red shoulder patches to attract mates and will puff them out to catch the eye of a female. White-breasted nuthatches on the other hand are a little more drab in coloration which may help in camouflage and likely makes it harder to see them hopping along on trees. Birds will develop different coloration depending on the pressures they face, in the case of red-winged blackbirds it may be sexual selective pressures and by comparison, white breasted nuthatches may have more pressure of predation.

There was also a group of european starlings sitting high up in the trees. They were all resting which fits into the context of their circadian rhythm with getting ready for the sun to go down and to sleep. Birds like starlings are generally more active in the morning so it was not surprising to see them all resting in the trees.

I did not come across any chickadees this time but I have done “pishing” to try and attract them before. This sound may be so enticing to small birds because the noise emits a very wide range of frequencies. Some think it could be related to it sounding like an alarm call and often birds exhibit a mobbing behavior to drive way predators which may be why they are attracted to the sound.

Ingresado el 25 de marzo de 2019 por michaelmcg michaelmcg | 2 observaciones | 0 comentarios | Deja un comentario