Tuesday, February 5, 2013

Crow migration? Raven's in Michigan?

Do Crows migrate in winter? My friend says they do, and that most Crow appearing birds are actually Ravens....I think she's mistaken. Thank you for your help! ~ Dave
 .

Copyright © 2011 Cornell University
Click on All About Birds image for more ID help.
While crows and ravens are both highly intelligent birds and may look similar at first glance, at second glance you can distinguish clearly different behaviors, habitats and even physical characteristics.

We have American Crows year-round in Michigan and it’s not uncommon to see them, especially on garbage day, picking through your neighbors' leftover chicken wings. Most crows prefer open areas with nearby trees like in the suburbs, parks, woodlots, and forest edges. Some crows remain on their territories during the winter gathering in large winter roosts and large flocks searching for food. Winter roosting behavior begins in autumn and peaks mid-winter.

Crows, from tens in the north to hundreds of thousands in the south, will assemble in the late afternoon hours in an area with large trees. However some American Crows do migrate. Researchers have found marked crows from southeastern Michigan as far south as Tennessee, but more often migrants go shorter distances in search of food sources.

The American Crow’s cumbersome sounding scientific name Corvus brachyrhynchos is Latin for “raven with the small nose.” American crows can be distinguished from Common Ravens Corvus corax most easily by size (ravens have a much larger wingspan and well-developed ruff of feathers on the throat, which are called 'hackles'), by voice (ravens are hoarser), by the bill (ravens have heavier, "roman-nosed" bills covered by bristly feathers), and by the shape of the wings and tails (ravens' tails come to a point and crows have a rounded tail).

Copyright © 2011 Cornell University
Click on All About Birds image for more ID help.
Common ravens glide and soar more often than American crows and prefer open landscapes, such as treeless tundra, seacoasts, open riverbanks, rocky cliffs, mountain forests, plains, deserts, scrubby woodlands and now some parts of their range is found in urban areas. Their Michigan range is the Upper Peninsula and northern Lower Peninsula, and they are common in the jack pine forest.

Ravens often forage in larger groups in areas where resources are concentrated like in landfills, and non-breeding individuals may occupy communal roosts. But most ravens are seen alone or in pairs. Breeding pairs establish nesting territories, which vary in size with the food available in the area. Migration has not been recorded in common ravens, but populations can make short seasonal movements to avoid extreme weather.

For more identification tips and to see a side by side comparison go to Cornell Lab of Ornithology’s page Similar Species: Crows and Ravenshttp://www.allaboutbirds.org/page.aspx?pid=2501

Thank you for your question. I hope this helps. Remember to take part in this years Great Backyard Bird Count: http://www.lansingwbu.blogspot.com/2013/02/everyone-can-participate-in-great.html 

Related Articles:
at

No comments:

Post a Comment