2020 Songbird Nest Box Results

In the year of the pandemic, one outdoor citizen science activity that individuals or couples could safely participate in and enjoy is monitoring songbird nest boxes. 2020 was a very good year for songbirds using nest boxes at Goose Pond Sanctuary and Erstad Prairie, and on partner’s lands. Below is a summary of this citizen science effort, made possible because of the great work of volunteers.

Photos below: Tree Swallow (Kelly Colgan Azar), Eastern Bluebird (Pat Ready), House Wren (Kelly Colgan Azar), and Black-capped Chickadee (Arlene Koziol)

Tree swallow numbers declined 49% between 1966 and 2014, and they are one songbird that really benefits from people that erect, maintain, and monitor nest boxes. In 2020 alone, we fledged an amazing 434 tree swallows from the 100 boxes at Goose Pond Sanctuary, plus our partners fledged an additional 261 tree swallows fledged from their boxes. An average of 4.34 young fledged in the 100 boxes at Goose Pond is very high, considering a few boxes were not used.

Last summer, JD Arnston from Arlington reported a first from his observation of eight tree swallows fledging from a single box! This is a first that we can remember of even having eight eggs. If this continues we may have to increase the square inches of the boxes.

Tree Swallows always place feathers in their nests. Start of a nest. Photo by Mark Martin

Goose Pond, with its water and tall grass prairies, provide ideal habitat for tree swallows. Bluebirds are ground feeders and like to feed in short grass on cutworms. Since there is very little shortgrass at Goose Pond we rarely have a brood of eastern bluebirds.

2020 Songbird Nest Box Results, table created by Goose Pond Sanctuary staff

Photo by Pat Ready

From the spreadsheet you can see that bluebirds like oak savannas and  golf courses. Our friends the house wrens (see nest image, right) prefer wooded habitat, and this was a banner year for them. The nest boxes at Pleasant Valley Conservancy are mostly in oak savanna habitat, and the Sun Prairie Golf Course may lack water in the local area for swallows. Black-capped chickadees are uncommon finds in our nest boxes. When we find a pair of chickadees we immediately place a one inch diameter hole over the larger entrance to keep tree swallows from disturbing the chickadees. We have 2.5 inch spare “holes” that we screw in place.

Monitoring nest boxes is something for people aged from 6 to 96. “Bluebird Man”, 96-year old Al Larson, with the Golden Eagle Audubon chapter from Boise, Idaho, has been busy for decades helping western and mountain bluebirds. Last year he monitored 350 boxes and banded over 900 bluebirds. And we thought we were doing good to have all of our volunteers monitor 223 nest boxes! 

Bluebird nest box, photo by Alrene Koziol

If you would like to help songbirds, this is an excellent time to build or purchase nest boxes. Members of the Bluebird Restoration Association of Wisconsin (BRAW) have been leaders in Wisconsin in restoring bluebird numbers. BRAW recently placed an ad in a recent issue of Wisconsin Outdoor News offering new members at the $25.00 level up to 5 bluebird boxes, predator guards and pole clamps, an information package and four issues of Wisconsin Bluebird. However, at this time “Due to overwhelming response our nest box promotion is temporarily on hold.”  We are glad to see the high level of interest. Pat Ready, Madison Audubon volunteer, is the President of BRAW and the latest newsletter reports that members fledged the following: 19,385 bluebirds, 7,957 tree swallows, 894 chickadees, and 5,067 house wrens. We encourage you to join!

If you can’t erect nest boxes because of your location or situation, you can still help by simply becoming a member of conservation groups like Madison Audubon, BRAW, or many other organizations. Giving a membership to family and friends as birthday or anniversary gifts is an excellent way of bringing new people and resources to these conservation organizations. It has never been easier to help the environment in this way.

The 1,159 fledged songbirds would like to thank our monitors. If you would like to help monitor nest boxes on preserves in Columbia County contact Graham at gsteinhauer@madisonaudubon.org.

Written by Mark Martin and Susan Foote-Martin, Goose Pond Sanctuary resident managers, and Graham Steinhauer, Goose Pond Sanctuary land steward; edited by Brenna Marsicek, Madison Audubon director of communications & outreach

Cover photo by Lorie Shaull FCC

Brown-headed Cowbird

I came across this post from the Voyageurs Wolf Project on Facebook two weeks ago. The page is informative and worth a follow, and this post reveals a fascinating development in the ecology and behavior of wolves!

Of course, this is an April Fool’s joke. At first, I thought wolves were raising a bear, but it turns out these fictitious wolves were raising a sasquatch. It is all very ridiculous.

Enter the brown-headed cowbird, which actually — and successfully — pulls off this very ridiculous stunt on birds across North America, tricking another species into raising its young. While wolves raising bears and sasquatches is absurd; it is also very cute. Cowbirds, on the other hand, do not receive the benefit of the doubt regarding their cuteness when a poor yellow warbler is tasked with rearing a cowbird chick—a yellow warbler which might end up being 1/5th the size of the fully grown cowbird.

A yellow warbler foster mom with her giant brown-headed cowbird chick. Photo by Emilie Chen FCC

If we think of the yellow warbler as a full-sized wolf of 70 pounds, the black bear (brown-headed cowbird) it raises will be about 318 pounds, which is well above a healthy black bear male’s average weight of about 275 pounds.

The key difference: a yellow warbler raises that cowbird chick in the span of weeks, whereas the black bear takes at least a decade to become that size.

Sidenote: you can learn even more about cowbirds from Matt Reetz’s fantastic Evenings with Audubon presentation here, or in Carolyn Byer’s awesome Into the Nest feature called Cowbirds, everybody’s favorite villain.

Birds might be crudely classified as “things with feathers,” but that way of thinking obscures the incredible variations and adaptations of species, and the brown-headed cowbird probably gets overlooked despite its fascinating life history. E.O Wilson, in his book The Diversity of Life, states that the test of a complete adaptive radiation is “the existence of a species specialized to feed on other members of its own group.” The cowbird brings a twist to this parasitism; it tricks the host bird into feeding its young.

A wood thrush with its own and a brown-headed cowbird nestling. Photo by Kelly Colgan Azar

There are many admirable traits in cowbirds. The females are absolutely prolific at finding nests. Wisconsin just completed its second Breeding Bird Atlas. I participated in the search to find evidence of bird breeding activity—a fun but challenging enterprise. Looking for courtship or copulation, nests with eggs, birds carrying nesting material or food, or recently fledged young, among other things, is tasking. But cowbirds, laying up to 40 eggs in a season, manage to locate and lay eggs in dozens of nests. Upon reflection, I think I should have trained a cowbird female, like a falconer, to accompany my nest-finding expeditions.

Perhaps most impressive, the females then relocate each nest after they lay their eggs. With an enlarged hippocampus compared to males, these female cowbirds have the genius and persistence to bring their eggs into the world.

Mike Ehrmantraut, the famous character from Breaking Bad and Better Call Saul, said “there are two kinds of heists: those where the guys get away with it, and those that leave witnesses.”

The brown-headed cowbird female makes sure she leaves no witnesses. She is Ehrmantraut-esque in her ability to find and stake out the nest. Many scenes in Breaking Bad depict Mike staked out in his car for hours on end, where he eventually notes an interesting habit or behavior of the person he’s watching. Likewise, the female brown-headed cowbird swaps Mike’s 1988 Chrysler Fifth Avenue for brushy fencerows, field edges, and forest clearings—often a result of human disturbance. Here she watches her prospective host, and once a routine is discerned and the host leaves the nest to feed, our female cowbird races to the nest and quickly lays her egg. The deed is done.

Mike Ehrmantraut, observing from his car

Female BHCO, observing from her branch. Photo by Kelly Colgan Azar

But the work for the female is not done. While some opine cowbirds as deadbeats and lazy, the female stays vigilant, watching “her” nests. The cowbird will sometimes appear at a visible spot near the hosts and ensure that the eggs are being cared for. It’s as if the host parents are a witness about to give testimony to bring down a criminal enterprise, but the cowbird appears like a mafioso in the courtroom, and the testimony changes. Again, the behavior might be unsavory, but it is undoubtedly savvy.

What happens if these host birds testify? Many do, and American robins and brown thrashers can successfully eject cowbird eggs and fend off the cowbirds. Other birds will abandon the nest or build a nest on top of the previous one. Yet many birds are maladapted to cowbird parasitism. Researchers have found that when cowbird eggs are removed, the cowbirds will often return to the nest and teach a grisly lesson, destroying the remaining brood. The cowbird philosophy seems again pulled straight from the mouth of Mike Ehrmantrout, who said “The moral of the story is: I chose a half measure, when I should have gone all the way. I’ll never make that mistake again.” There is no half-measure with brown-headed cowbirds; if its egg is ejected, a tit for tat pattern will ensue.

There’s a fascinating Radiolab episode called “Tit for Tat” which explains the prisoner’s dilemma apparent during the Cuban Missile Crisis. One researcher ran a computer tournament where programmers tried to solve the prisoner’s dilemma and faced off against each other. Stacks of code were written, but the winning result was simple. Its first line was “be nice.” The second was “copy the other player’s move.” The program was called “tit for tat.” We see that this is an enthralling solution under this competitive environment. The episode goes on to describe how British and German soldiers, in the trenches during World War I, ended up engaging in a similar sort of scenario. At the lunch hour, both sides learned to cease fire. During Christmas of 1914, British soldiers crawled out of their dark trenches, drawn by the Germans candlelit trees and singing of “Silent Night”. Instead of shooting the exposed British soldiers, both sides decided to have a truce, and they mingled, traded, and drank—and the whole truce lasted a week in some instances. It’s as if, in the darkness of the front lines in December of 1914 the soldiers came together and found their shared humanity.

Back to our cowbirds, at about 20-25 days the juvenile in the host nest will become restless, and like those soldiers during World War 1, the bird sneaks off into the night. These young cowbirds do not find a Christmas truce, but they do find, apparently, their “cowbird-ness.” A clandestine meeting occurs, where the juveniles fly to cowbird roost sites around fields and spend the evening with other cowbirds. Experimental juveniles raised only by their host will end up learning the songs and calls of the host species.

Brown-headed cowbird club, photo by Patricia Pierce FCC

So, in a secret meeting in the middle of the night, the cowbird learns that like the popular mafia front of “waste management” the cowbird family business is “nest management,” and the juvenile returns to the host’s nest by morning, its identity known but its disguise burgeoning—the strong, silent type.

Written by Drew Harry, Faville Grove Sanctuary land steward