Ask most birders or hawk watchers around the country about famous sites they’ve heard of, and I’d guess no one from Illinois would be mentioned. But Illinois is home to three successful all-volunteer-run hawk watch sites that are conducted every fall. The first one, the Illinois Beach State Park Hawkwatch, located in the northeastern corner of the state near the Wisconsin border along the shoreline of Lake Michigan, began in the year 2000. Observers at Illinois Beach average a little over 600 hours per season, with an average of 5165 raptors counted. That number in and of itself may not be too impressive, but Illinois Beach has one noteworthy distinction.
No hawk watch site west of the Atlantic Coast sites tallies more Merlins than Illinois Beach does, with an average seasonal count of 408 over the 20 years. Illinois Beach’s October 9, 2007 total of 708 Merlin still ranks amongst the highest for a single day total ever in North America. Illinois Beach is also a participating site in the Raptor Population Index (RPI), co-sponsored by four leading raptor organizations in North America. More information can be found at RPI. Moving further down the Lake Michigan shoreline, only 17 miles away, is the Fort Sheridan Hawkwatch. This site formerly began in 2013 as an exploratory site to compare sightings with Illinois Beach on good days for raptor migration.
In that first year, only 88.75 hours were put in. But in that short amount of time, raptor counts compared to Illinois Beach showed some interesting differences. Not only in daily totals but also in what species were sighted. Now, seven years later, Fort Sheridan is on its way to becoming another successful all-volunteer Illinois site that will hopefully teach us something about raptor movements along the shoreline of Lake Michigan. The third established all-volunteer site in Illinois, the Greene Valley Hawkwatch, was started in 2006. It is located approximately 52 miles in a straight line from Illinois Beach and inland about 25 miles from the shore of Lake Michigan. The site itself is situated on a hill at a closed landfill. Being an inland site, overall numbers are different than the other two sites in Illinois, but one species stands out.
It was long suspected even before Greene Valley was started that Broad-winged Hawks were generally migrating away from the shoreline of Lake Michigan. And although the longevity of the three sites is slightly different, the average annual Broad-winged Hawk total for Greene Valley surpasses the other two sites. Greene Valley average per year is 1436 Broad-wings compared to Illinois Beach with 1078 per year and Fort Sheridan with 1206 per year. Several other areas of our continent have multiple sites close to each other. It is presumed and hoped that something can be learned by comparing data at these sites and their relationship. The three locations in Illinois are beginning to realize the potential for further research into this love we all have for raptor migration.