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

Hooded Merganser

Hooded merganser, photo by Mick Thompson

We always enjoy seeing hooded mergansers, especially when the males have their crests — also known as their “hoods” — raised and are in courtship display. The scientific name for hooded mergansers is Lopodytes cucullatus that means “hooded diver.” The crests can be raised and lowered in both sexes, and are a helpful identification guide for these small fish ducks, who with their narrow serrated bills, catch fish.  

Early naturalists in the 19th century listed hooded mergansers as “abundant” in Wisconsin and were found especially in forested areas near water. But Sam Robbins wrote in Wisconsin Birdlife in 1991 that hooded mergansers are uncommon summer residents in southeast Wisconsin. Columbia and adjacent counties were not not included in his breeding map for the species. Their numbers greatly declined due to loss of forested habitat that provided nest cavities and over harvesting by hunters. Sam wrote that “Theoretically, the bird’s summer range should blanket the state.”

According to the Cornell Lab of Ornithology “Hooded Mergansers are fairly common and their populations are stable and possibly increased between 1966 and 2015, according to the North American Breeding Bird Survey.”

Hooded merganser range map, provided by The Cornell Lab of Ornithology

We observed their numbers increase in Columbia County in the past four decades. In the 1980’s, we would see a few birds usually in spring migration. In the 1990’s, we began seeing a few nesting pairs. In the first Breeding Bird Atlas (1995-2000), hoodies were confirmed nesting in 12% of the statewide priority and 17% of the priority blocks in Columbia County. In the second Breeding Bird Atlas II (2015-2019), they were confirmed in 26% of the statewide priority blocks and 33% of the Columbia County priority blocks.

A freon nesting tube that was donated to us by the LaCrosse County Conservation Alliance. We replaced the freon tube with a cedar box. Photo by Richard Armstrong

Hooded Mergansers at Our Cabin Near Rio

We had two surprises on March 25th when we began our final check of our duck nest boxes at our cabin near Rio to make sure they were ready to go. The first surprise was finding two boxes that contained screech owl pellets. One of the boxes also contained a small uneaten bullhead. Usually one does not think of owls that go fishing.  

The second surprise was finding two nest boxes with hooded merganser eggs. One box had four eggs and the other had two eggs. So far at the cabin we have three merganser nests with the first eggs laid on March 21, 23 and April 1st. An early ice out and above normal temperatures probably contributed to the early egg laying.

Lovely merganser eggs. Photo by Mark Martin

Our plan at the cabin is to check 20 accessible nest boxes weekly and stop checking individual boxes after finding woodie or hoodie eggs. We also have three nest boxes with wood duck eggs that were first laid on April 3, 4, and 5.  

Nesting Hooded Mergansers at Goose Pond

Goose Pond contains an abundant population of fathead minnows, probably ideal prey for these small diving ducks. But in the past, the property lacked large trees with nesting cavities. That changed in 2015 when we erected two cavities as wood duck boxes. One box was placed at a wetland at Sue Ames Prairie and the other just west of the railroad tracks in the wetland south of the Kampen Road residence.

A hooded merganser nest was found on May 12 at Sue Ames Prairie. We checked the nest box on May 18th and the young were ready to jump out. Nine membranes from hatched eggs and one unhatched egg. This was the the first hooded merganser nesting at Goose Pond. Photo by Mark Martin

On May 12, 2016, Mark, Jim and Kathy Shurts, and grad student Heather Inzalaco conducted a big day count and Mark decided to check the nest box at Sue Ames Prairie. Mark slowly opened the side and could see an incubating female hoodie - what a surprise and a treat! Mark checked the box again on the 18th and nine young were getting ready for “jump day”. This was probably the first record for a hooded merganser nest at Goose Pond! 

Hooded mergansers have used this box every year since 2016. Last year the box contained a large clutch of eggs that did not hatch. We speculated that the female abandoned the nest, was killed, or that this was a dump nest and not incubated.   

However, one evening last July we looked out the large south window of the house on Kampen Road and saw a large brood of hooded mergansers! We were fortunate to watch them grow up. The brood started with 14 young and ended with twelve. The nest box near the brood was checked and many egg membranes and three unhatched eggs were found. Our guess is that both nest boxes were dump nests and only one was incubated. Late last month, Graham Steinhauer checked the box at Sue Ames and found a hoodie nest with the first egg laid on March 26th. 

Hooded merganser cuties, photo by Mick Thompson

When we put up our “wood duck” boxes, our goal was to attract wood ducks, and did we not expect to have nesting hooded mergansers. As of 2020 we still do not have any records of nesting wood ducks, but the hooded mergansers are sure making themselves at home!

A question that some visitors ask is, “Why aren't male hooded mergansers present in Columbia County after mid-April?” It is often mentioned when looking up information on hooded mergansers that after the hen begins incubating the male takes off. Most waterfowl biologists believe they head to wooded river systems and may travel long distances.

Special thanks to Mark and Jenny McGinley who have been erecting, repairing, cleaning out and monitoring 41 wood duck boxes for the past 11 years that at the Anderson Waterfowl Production Area (WPA), Jackson WPA, Otsego Marsh and Schoeneberg Marsh WPA/Erstad Prairie. All areas have high numbers of nesting woodies and hoodies.

Jenny McGinley checks on of their many wood duck boxes, this one at Otsego Marsh. Photo by Mark McGinley

In the past eight years, Mark and Jenny found 193 successful nests including 123 (64%) nests that were only wood ducks, 31 (16%) that were only hooded mergansers, and 39 (20%) that contained eggs of both species (dump nests). Both species can also lay eggs in the nest of their species. Mark and Jenny have found dump nests with up to 33 eggs! Large clutches usually do not hatch since a female would have a hard time incubating large numbers of eggs.

Hoodie females begin nesting at age two, usually lay a clutch of 10 eggs and incubate the eggs for 32 days while woodie females begin nesting their first year, usually lay a clutch of 12 eggs, and incubate for 30 days. It is easy to look at eggs and identify the species since hooded merganser eggs are large, white, thick-shelled and spherical contrasting to smaller, brown, thinner-shelled, oblong eggs of the wood duck. It is assumed that since wood ducks have a shorter incubation period that more wood duck eggs might hatch in dump nests that also contain hooded merganser eggs. We assume that if a female wood duck is checking out nesting cavities and finds a defensive hooded merganser already nesting that she would look for another cavity.

A wood duck box should have a solid predator guard to protect the eggs from hungry raccoons and other critters. Photo by Mark Martin

Consider putting up a nest box to attract a breeding pair. Attach a predator guard to keep predators from raiding eggs and young.”  Note that “wood duck box” blueprints work well for attracting hooded mergansers. Here are some instructions published by National Audubon on how to build a duck box. Some people use pine, but we recommend cedar for its excellent rot resistance. Be sure to add a predator guard as raccoons and other critters love to eat duck eggs.  

If you would like to see a brood of hoodies visit Schoenberg Marsh Waterfowl Production Area adjacent to Madison Audubon’s Erstad Prairie, or MAS’s Otsego Marsh property south of Rio. The young are fun to watch diving, feeding and interacting.  

Written by Mark Martin and Sue Foote-Martin, Goose Pond Sanctuary resident managers

Sandhill Crane

Sandhill crane pair in calling in unison at Goose Pond. Photo by Arlene Koziol

One of my favorite birds is the sandhill crane. Their appearance, ecology, resilience, and their signal of spring all appeal to me. They also brought my wife, Sue, and I together. What’s not to love?

Sandhill numbers have had changed dramatically in the past 175 years. Kumlin and Hollister, early ornithologists in southeast Wisconsin, believed that sandhills were an “abundant and common migrant” around the 1850’s.

Sam Robbins wrote in Wisconsin Birdlife (published in 1991) that people thought that crane numbers greatly declined around the early 1900’s due to hunting, and wetland drainage for agricultural development.

In the mid 1930’s the state wide population was estimated at around 25 pairs mostly in west central Wisconsin. Aldo Leopold thought that sandhill cranes would disappear from Wisconsin and penned “A Marshland Elegy” in the 1940’s to mourn that idea.

Students at UW Stevens Point began studying cranes in the 1970’s. Ernie Gluesing conducted an aerial census and estimated the state population at 850 in 1973. He also studied crane territories and reported that territories averaged 339 acres.

In the 1970’s I enjoyed fall visits to the area around Muir Park in Marquette county where several hundred sandhill cranes staged and fed in the surrounding area. The Fish and Wildlife Service acquired the large wetland complex adjacent to Muir Park for the cranes. At that time cranes were still uncommon in Dane and Jefferson counties.

In the mid 1970’s the International Crane Foundation began their annual sandhill crane count that now covers parts of six states.

I fondly remember attending a February 21, 1978 meeting at Piason’s restaurant to discuss the Dane County crane count. My friend Dorothy Haines was there and brought along her friend Sue Foote. I apparently made a memorable impression on Sue when I ordered milk with my pizza. (You might know the rest of that story: we dated, married, immediately moved to Goose Pond Sanctuary to take over as resident managers, and have been there ever since!) Ron Sauey, co-founder of the International Crane Foundation, joined us and later that evening, according to my diary, gave an “excellent talk on Siberian cranes” at the monthly Audubon meeting.

Two sandhill cranes in flight. Photo by Arlene Koziol

Sam Robbins wrote sandhill cranes were that cranes were an uncommon migrant and uncommon summer resident. Sam also mentioned crane researcher found nests with eggs as early as April 22 and that most cranes left Wisconsin in October following the start of the waterfowl hunting season.

Crane numbers and biology have changed much since the 1970’s. The first Breeding Bird Atlas (1990’s) found cranes incubating by March 22. Cranes also nest on small wetlands and appear to have smaller territories. Cranes do not leave Wisconsin when waterfowl hunting season begins. Thousands of cranes stage at Crex Meadows in Burnett County and along the Wisconsin River in Sauk County by the Leopold Shack and Foundation, and do not usually leave until November.

Sandhill crane building a nest at Goose Pond, April 8, 2019. Photo by Arlene Koziol

Crane numbers have also greatly increased in Columbia County. In 1995, Sue and I recorded the first sandhill crane nest at Goose Pond and continue to participated in the annual crane count. This year, I counted at Goose Pond on April 13. I was excited to be up before dawn and wondered what I would find with record amount of water. It did not take long to hear and see cranes and ended up finding three pairs and two individuals. Usually there are a pair of cranes on the west pond and a pair on the east pond.

Goose Pond was alive with birds. I counted 37 species of birds by 7:30 a.m. and ended the day finding five more species. Highlights that day included 16 species of ducks, a flock of 25 white-fronted geese, two horned grebes, large numbers of American coots, and a pair of northern harriers with the male in courtship display. At dusk I was treated to seeing a short-eared owl hunting about 50 yards east of the house.

Sandhill cranes on the nest. Photo by Arlene Koziol

There are two pairs nesting on the west pond with 40 yards of Prairie Lane and Goose Pond Road and probably a pair in the Manthe wetlands on the east pond. Sue and I hope you can visit this summer and enjoy these fascinating birds along with the other wetand and grassland birds.

Written by Mark Martin, Goose Pond Sanctuary resident co-manager