Breeding season is upon us at Nature Boardwalk at Lincoln Park Zoo. Baby snapping turtles have been spotted, adult dragonflies are often seen flying in tandem and numerous swallow species, sparrows, and, of course, black-crowned night herons are nesting in or around the area.
One of the more recognizable bird species nesting at Nature Boardwalk this year is the red-winged blackbird. The males of this species are easily identified by the red shoulder patches on their wings while the females are more the color of this fledgling I spotted on Nature Boardwalk’s southwest side.
The mild winter and consistent sunny days have given the plants around the edge of the pond a chance to start growing earlier than expected. Accordingly, these birds, which didn’t nest at all at Nature Boardwalk last year, have already had their first brood! Given the right habitat red-winged blackbirds will actually have two to three broods in a breeding season, making a new nest every time to decrease the chances of parasites invading the nest.
Building new nests for each brood is not something all bird species do; no doubt red-winged blackbirds increase their ability to reproduce by doing so. It’s no wonder these birds are one of the most abundant avian species in Illinois!
At Nature Boardwalk these birds will actively eat almost anything they can get a hold of. Aquatic invertebrates, dragonflies, spiders, caterpillars and seeds are all tantalizing to these blackbirds. Since Nature Boardwalk has a multitude of all of the above, I assume we’ll be seeing even more blackbirds in the months to come.
In addition to all the new arrivals, you may have noticed that the pond at Nature Boardwalk has developed algal blooms over the past several years, which are common in small ponds and lakes throughout much of the United States. These blooms are caused by phosphorus entering the water, which is not harmful to fish or wildlife. The zoo is working to reduce and control the phosphorus levels and keep algae levels low throughout the summer.
Since Nature Boardwalk opened, though, we have seen almost 120 different bird species, 23 different dragonfly species, and a great variety of aquatic life. All indicate that Nature Boardwalk is a vibrant and healthy environment.
Mason Fidino is coordinator of wildlife management in the zoo's Urban Wildlife Institute.