Your Questions

Paul in Greeley Colorado writes:

What is the difference between a crow and raven? I live close to Rocky Mountain National Park and want to learn the difference since both crows and ravens should be around, shouldn't they?

Ravens are similar to crow species except larger and shaggier around the throat. Ravens are as big as Red-tailed Hawks.

Compared to crows, ravens fly more like hawks by soaring and with shallow wing beats. Ravens sometimes do a "somersault"  in flight (while crows never do).

Ravens have deeper, more hoarse calls than crows.

Listen to a Common Raven

Listen to an American Crow

Ravens are found throughout most of the Northern Hemisphere although they are rare in some areas of Eastern U.S. American Crows can be found throughout North America, except in driest southern areas and where replaced by Northwestern Crow in Washington. You are likely to find Ravens in locations where it can soar on rising hot air (thermals) and where there are cliffs or tall trees for nesting. American Crows are likely to be found in a variety of habitats, including suburban areas and agricultural lands.

Still want to know more? Visit Dr Kevin McGowan's crow FAQ page to learn more about telling crows and ravens apart.

To learn more about comparing North American black birds click here.

Elena Bardot in Misión Viejo CA writes:
I have been watching crows for a long time near my home in California (I am from Argentina where there are no American Crows) and every evening I have observed enormous groups of crows fly in the same direction, at the same time of day. Where are they going?

If you observe large groups of crows flying in the same direction in the evening, you are watching crows headed towards a roost. You also may see large numbers of crows leaving their roost as it gets light in the morning. Roosting occurs when groups of birds gather together for the night. Crows congregate in large roosts in fall and winter. They may gather in groups that range from under one hundred crows to enormous roosts of hundreds of thousands, or even more than a million crows.
We're not sure why crows roost in such large groups. Perhaps they are congregating in preferred areas. Alternatively, their large numbers may protect them from predators. It is possible that roosts serve as information centers where crows watch one another to learn where they are finding food or shelter. One of the goals of Crows Count is to better understand urban roosts and how they change through the seasons.

I also would like to know how to count such large numbers of crows and how to identify the sentinels.
Counting a large group of birds can be challenging. Make sure that you have established your Study Site first and only count the crows in your Study Site. Begin by counting a smaller group of crows (10 birds or so) within the large group and then count the number of groups that look to have about the same number of birds. Multiply the number of groups by the estimated number of crows in each group. Use your highest estimate as the final count. Don't be afraid to estimate!
A sentinel is 'one who watches or guards'. If you see one or more crows looking around as they sit upright on a high perch above or near other crows, they are most likely sentinels. Sentinels will not be eating or preening. They will be alert and observant, seemingly watching for trouble. You won't always see sentinels in a group.

Mary McMahon, St. Louis, Missouri, writes: We are very concerned about the crows here in St. Louis, Missouri. Will they recover and become immune to West Nile virus?

West Nile virus is transmitted by mosquitoes. Infected mosquitoes carry the virus from one bird to another and, less commonly, from a bird to a human. Crows and other members of the Family Corvidae (ravens, jays, and magpies) are particularly susceptible to West Nile virus and they test positive for the virus more frequently than other birds. Forty-four percent of dead crows collected in New York have tested positive for the virus (although they often die from the virus, the cause of death was not determined). A small percentage of live crows have tested positive for West Nile virus. It is possible that these birds got sick and recovered.
Data from the Lab's Project FeederWatch suggest declines of some species, including American Crows, in the Midwest where the virus hit particularly hard in summer 2002. In some areas, the midwestern crow counts decreased by about 70 percent from 2002 to 2003. But in other parts of the country, American Crow counts increased by 6 percent. Additional citizen-science projects, such as Christmas Bird Count and the Chicago-area Bird Conservation Network, have documented dramatic declines for corvids in Illinois.
Should we worry about our crows? I don't think so. Although their numbers might be devastated by the virus, crows in North America have very large, widespread populations, making them fairly resilient to local extinctions. In addition, the increase in numbers outside of the Midwest (including areas where previous West Nile virus outbreaks have occurred) demonstrate their potential for recovery.
Everyone can help us better understand the changes in crow numbers by participating in Crows Count . Help us keep track of all of our crows and their relatives! Anyone can participate-it's fun and easy.

Read more questions about city birds!