Evaluating Nesting Success of Black-Capped Chickadees at Nature Boardwalk

Zoo scientists are building specialty nest boxes to encourage black-capped chickadees to nest at Nature Boardwalk at Lincoln Park Zoo.

 

It’s been almost three years since the creation of Nature Boardwalk at Lincoln Park. The native plant community has become well established, creating natural habitat for many different species right here in the heart of Chicago.

Last year zoo biologists noted an increase in native birds nesting around the boardwalk. Red-winged blackbirds nested en masse in the bulrush surrounding the pond, and Baltimore orioles and house finches used the oak trees next to the People’s Gas Education Pavilion.

All this nesting represents a great success for Nature Boardwalk. However, one group remains conspicuously absent from the boardwalk during breeding season: cavity-nesting birds.

What Is a Cavity-Nesting Bird?
Cavity-nesting birds nest in chambers inside trees. Woodpeckers, eastern bluebirds and nuthatches are all examples of this group. There are more than 80 different cavity-nesting bird species in North America. Of these, some excavate their own cavity to nest in while others use old excavated cavities or find tree cavities caused by natural decay. Tree cavities don’t just play a critical role for these bird species; many mammals, including bats, also use this habitat to roost.

In natural areas, cavity-nesting birds commonly use standing dead trees (snags) for nesting, perching and foraging. Snags are commonly removed in urban areas for safety concerns or aesthetic reasons, though, causing a decline in the number of cavity-nesting sites available.

Making matters worse, cavity-nesting birds often have to compete with urban invasive species with higher population densities. For example, the house sparrow is one of the most abundant invasive species in urban areas due to its ability to adapt to a human-modified landscape. These birds are a significant competitor for local cavities.

To try to help our cavity-challenged friends, Lincoln Park Zoo’s Urban Wildlife Institute has set out to encourage one particular local species to nest at Nature Boardwalk: black-capped chickadees.

Bringing Chickadees to Nature Boardwalk
Black-capped chickadees are well known for their ability to nest in suburban and urban landscapes, making them a prime candidate for urban conservation. These small birds can also provide insight into the challenges urban cavity nesters face while raising young.

To study this particular species we have placed 20 artificial cavities (nest boxes) around Nature Boardwalk that we will be monitoring now through the end of the breeding season (late July). Since black-capped chickadees are much smaller than house sparrows, these nest boxes were designed to have a very small entry hole on the front that should allow chickadees to fit through while excluding the larger house sparrow.

One of the nest boxes, with part of the Chicago skyline in the background.

This study has just started at Nature Boardwalk, and it’s still too early to see nesting activity, but we are very excited to see if the chickadees will discover these new cavities. If you see any of the nest boxes, please observe them from a distance, as we don’t want to spook our new neighbors at the boardwalk!

Funding for this project was graciously provided by the North American Bluebird Society.

Mason Fidino

Mason Fidino is coordinator of wildlife management for Lincoln Park Zoo's Urban Wildlife Institute.

  Follow the Urban Wildlife Institute on Twitter.

 

Comments

FYI - Saw Black Crowned Herons on the other side of the LaSalle overpass today (4-6-2013) near the Lincoln Memorial statue. There were 5 herons there, none on the other side near the South Pond. I wonder if they will all migrate to the other side of the Park near the statue and North Avenue. If so will the Zoo provide enclosures and watch the site?

In previous years herons have not started occupying the allee until they had sufficient numbers (50-100 herons). While the number of BCNH are increasing in the park daily, they are often seen in other areas around the entirety of Lincoln Park until enough of them show up for them to move to the allee. Zoo staff are walking the entirety of Lincoln park daily to monitor herons that are present.

It is still too early for the herons to begin nesting (hatchlings are generally heard around the last week of May or early June). In the event that the herons do nest anywhere else other than the allee, zoo staff will monitor the nests and report this information to the Chicago Park District and the Illinois Department of Natural Resources, who will collectively decide upon the management strategy (e.g. putting up a fence) because those nests are present on park district land.

Letting us know where you are seeing herons is very helpful, thank you for letting us know!

I'm bringing a group of preschool students to take a walk on the Boardwalk the first week of May. Anything in particular worth looking for, paying attention to at this time?

Kirstin, Mason says, "For preschool students I highly suggest taking a look at the nesting black-crowned night herons, who will be just south of the boardwalk down two rows of trees. You will also see them on the island at Nature Boardwalk. The adults are black and white and are vaguely football shaped when they are standing on a branch. There will likely be hundreds by that time so you shouldn’t miss them!

Turtles will also be out that time. One highly preferred basking sites for the turtles at Nature Boardwalk is a rock on the southwest corner of the island. At times I have seen 5-10 turtles stacked on top of each other on this one rock."

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