When you think of migrating birds, the V-shaped formation of squawking geese, or the flock of sparrows taking flight.
What you may not know is, each day, thousands of hawks are using the Blue Ridge Mountains of southwest Virginia as a highway from getting from the cooler climates, to Central and South America where they'll spend the winter.
How do we know? People count them.
Volunteers with the Harvey's Knob Hawkwatch arrive like clockwork each September through the end of November, counting the daily migration of birds and logging the numbers on the website, HawkCount.org.
That data is submitted to the Hawk Migration Association of North America which is another all volunteer organization created in 1974 for the purpose of collecting and storing data from all hawk watching sites in North America.
The volunteers arrive just after sunrise, and sometimes don't leave until just before sunset.
"What keeps me coming back is seeing these beautiful creatures and the challenge of counting them, sometimes hundreds or thousands at a time," says Baron Gibson one of the volunteers.
Gibson will also tell you it's the people that keep him making the annual trip to the overlook.
During the afternoon count, a couple from India was travelling the Blue Ridge Parkway and stopped by the busier than usual overlook.
Like most, they asked lots of questions, then took the binoculars and gazed into the clouds hoping to catch a glimpse of the hawks flying overhead.
The group is always looking for volunteers. Qualifications? Binoculars, a love of nature and plenty of patience.
"Some days we see hundreds of birds, other times we can't keep up."
Visit the Harvey's Knob Hawkwatch Website for more information on the annual count.