The Potomac Valley Audubon Society has set Dec. 17 and 31 as the dates for this winter’s annual Eastern Panhandle Christmas Bird Counts.

These local-area counts are part of a volunteer-based Christmas Bird Count that has been conducted throughout the western hemisphere every year since 1900 under the auspices of the National Audubon Society.

The purpose is to monitor the status and distribution of early-winter bird populations.

Count volunteers follow specified routes through a designated 15-mile diameter circle, counting every bird they see or hear all day.

The Dec. 17 count, the Charles Town count, encompasses a circle that is centered near Charles Town and stretches from the Shannondale area at the east to near Middleway at the west.

The circle for the Dec. 31 count, the Inwood count, is centered near Shanghai in Berkeley County and includes the west side of Martinsburg and Inwood to the east and the Stotler’s Crossroads/Greenwood section of Morgan County to the west.

To register and/or to obtain more information, contact Bob Dean at 304-754-3042 or bobdean52@gmail.com.

Full information is available on the PVAS website at www.potomacaudubon.org.

The data collected from each year’s Christmas Bird Count are folded into what is now the longest-running database in ornithology, representing over 100 years of continuous information. This database is used to help spot trends in bird populations, which in turn can help identify shifts in environmental conditions.

The data from each year’s count are available online at www.birdsource.org (once there, click on “Christmas Bird Count.”). To view data from the Eastern Panhandle counts enter their official four-letter codes, WVCT and WVIN, in the appropriate field.