Nesting season has returned to Lake Renwick Heron Rookery Nature Preserve, which means access for humans will be restricted so as to not disturb the bird families residing there.
The preserve's main entrance on Renwick Road will close March 1 and will reopen August 16.
The entrance closes in the spring to protect all of the birds that congregate at the site, including herons, egrets, cormorants, pelicans, songbirds and more. The only way to access the site during this time period is by attending a scheduled program.
Chris Gutmann, facility manager at Isle a la Cache Museum, said great blue herons are already busy searching for the best nest sites and materials.
"They forage for nesting material on the main part of the preserve where they would be constantly flushed by visitors, if the preserve were open. During this process, a constant disruption could have a negative impact on nest construction and the birds’ use of the site."
Of the migrating birds that call the rookery home, great blue herons are among those most likely to arrive first, he said. "Usually by this point in February, some are already there. Double-crested cormorants, great egrets, and black-crowned night-herons arrive later."
Eggs are typically laid in April, said Dave Robson, the Forest Preserve's natural resource management supervisor. "Most of the herons and egrets have a two- to three-month incubation and nestling stage," he said. "Somewhere around the end of July, most of the young are considered fledglings and are near leaving the nest. Usually by mid-August, most of the nests are empty."
While the preserve will be closed for general use during nesting season, guided programs offered by the District in spring and summer allow visitors access to the nature preserve's viewing platform and scopes.
In April, three “Migratory Bird Hikes,” will be held from 8-10 a.m. on Saturdays, April 6, 20 and 27. Also, a “Photography Bird Hike” is set for 8-10 a.m. Saturday, April 20. Registration is required two days before each program.
“Lake Renwick Bird Viewing” programs also will be held from 8 a.m.-noon on Saturdays, May 4-August 10. Registration is not required. Bird-watching programs at the site are staffed by volunteers from the Will County Audubon Society.
VIEW UPCOMING PROGRAMS AT LAKE RENWICK
The 839-acre Lake Renwick Preserve is one of the most unique spots in the Forest Preserve District.
“The site is an important bird area in Illinois mostly due to the number and variety of water birds that can be seen at the preserve, although other avian types can also be observed,” Robson said. “At least 170 bird species have been documented at Lake Renwick Heron Rookery over the years, and the preserve continues to attract new species because of the availability of the isolated aquatic and wooded habitats that are rarely disturbed by people.”
Lake Renwick was established at a time when some bird species were struggling.
“It’s a former quarry that has been converted into a wildlife sanctuary,” Gutmann said. “It serves as a grand example that, with a little help from us, nature can return to even the most decimated sites in spectacular fashion."
The sanctuary is a perfect spot for bird-watching programs.
“There aren’t many preserves that provide the opportunity to see an American white pelican or hundreds of swallows swarming over the water at one end, and then encounter the beautiful song of a rose-breasted grosbeak or a stunning Blackburnian warbler at the other,” said Gutmann, who oversees programs at the site.
And while most people think of the water birds that live at Lake Renwick, there are many other species to enjoy – and protect, Gutmann added.
“It is an underrated preserve for songbirds. Forested areas support wood-warblers during migration. Everything from Baltimore orioles to the occasional scarlet tanager can be found there. Especially during spring and fall migration, there always seems to be a surprise or two waiting to be discovered.”
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