In general, populations of Eastern Towhees in the northern part of their range are short distance migrants, whereas populations south of Virginia tend to be year round residents. The last of northern New England’s migrating Eastern Towhees are departing for southern climes right now (a few brave souls stay put, and are seen intermittently during the winter, especially during warmer winters). Although we don’t observe them migrating, as they do so during the night, we do see them when they stop to refuel on fruits, seeds or insects during the day.
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
This week those of us in the Northeast have been inundated with dark-eyed juncos, often referred to as “snow birds” due to their presence in much of the U.S. only during the winter months. Although this member of the sparrow family breeds here and is found year-round in New England, over most of the eastern U.S. juncos appear as winter sets in and then retreat northward each spring. Many of the juncos that we are seeing now are transitory migrants on their way to Canada and the Arctic to their breeding grounds. They will remain there until next fall, when we will experience a similar influx. Research has found that males migrate earlier than females, and that females tend to migrate further south than males. The timing of this migration is regulated primarily by the lengthening spring days.
Countershading is a common color pattern in animals in which the upper side of the animal is darker than the lower side. This color pattern provides camouflage for the animal when viewed from the side, above or below. The counter shading pattern balances the sunlight on the animal’s back and the shadow beneath the animal so as to blend the animal’s side profile with its surroundings. In addition, when viewed from below, a counter-shaded animal with a light belly blends into the light coming from the sky above. When viewed from above, the darker back of a counter-shaded animal blends into the darker ground colors below. Birds (which spend a considerable amount of time in the air) such as this dark-eyed junco, as well as marine animals often exhibit countershading.