Greater White-fronted Goose

Record numbers of greater white-fronted geese (Anser albifrons) at Goose Pond 

Greater white-fronted goose, photo by Ryan Askren

Greater white-fronted geese (aka specklebelly) can be identified by their light belly with black checkers, streaks or blotches and orange legs. They are named for the white patch of feathers bordering the base of the bill, and the latin name albifrons is derived from albus meaning white and frons meaning forehead. At a distance they are difficult to pick apart from Canada geese, but they’re smaller, have a more rapid wing beat, and announce themselves with energetic squeaks (listen in here). This opportunistic species has a nearly circumpolar arctic distribution and in North America, white-fronted geese are distinguished by a Pacific and Midcontinental population. 

Families Stick Together

Adults arrive at the breeding grounds of Alaska and Canada in May. They select a pond, shallow lake, or stream shoreline with an abundance of sedges or moss on which the nest is built. So far they sound similar to other nesting geese of the north like snow geese and brant, right? There are a lot of differences, but this is one that I found particularly interesting. 

Family pair bonds last longer in white-fronts than other geese, and broods frequently stay with their parents for a multiple years. Pretend that a breeding pair successfully reared three young in 2019. Those three young are probably still with the parents. When the family group arrives back on the breeding ground in 2020, the three young from 2019 are likely to help defend their parents nest from predators and conspecifics, possibly throughout the breeding season. White-front aren’t sexually mature until they are two or three years old so in this situation, the young from 2019 will not compete for their parents' breeding territory in 2020.  

Satellite image of the Alaskan landscape preferred by white-fronted geese

Migration Changes in Wisconsin

Check out this great animated map, which tracks the spring and fall migration of greater white-fronted geese.

On their southward journey, white-fronted geese typically make two major hops. The first is from the arctic to grain fields in Saskatchewan and Alberta (about 1,400 miles), and then make another major move to the gulf coast and Mississippi Alluvial Valley (about 1,800 miles). They winter as far south as subtropical settings on the Yucatán Peninsula of Mexico. White-fronted geese take a much more leisurely approach to spring migration, and they utilize diverse habitats from deserts and grasslands to river deltas and major agricultural areas. 

White-fronted geese in flight, notice the variation in the coloring in the bellies. Photo by Arlene Koziol

According to Samuel Robbins Wisconsin Birdlife, white-fronted geese had “large numbers in spring and fall” or were even described as “an abundant migrant” in Wisconsin prior to 1890. Their populations in Wisconsin declined dramatically over the next two decades, and only a single observation of white-fronts was published between 1910 and 1938. While there were increasing observations after 1940, the 1990s in particular set the stage for a dramatic shift. This is where Columbia County comes in. Below is a short history of observations of white-fronted geese in Wisconsin provided by the Passenger Pigeon which is published by The Wisconsin Society for Ornithology.

1995 - Three counties. “Daryl Tessen had 13 in Outagamie County on 12 March and Bill Hilsenhoff had 17 in Dane County on 19 March.”

2003 - Ten counties. “The characterization of this species in Robbins Wisconsin Birdlife (1991) as a rare species reads like ancient history, with double-digit flocks now routine…Tessen was able to estimate well over 1,000 birds in Columbia and Dane Counties (combined) on March 29.”

2004 - 11 counties. “Numbers that would have been jaw-dropping even ten years ago peaked at 1,350 in Columbia County on March 20 (Tessen).” 

2008 - “The big numbers were in Columbia, Lafayette, and Dane Counties, peaking at 475 individuals in Columbia County on 13 April (Prestby).”

2012 - “By 8 March Tessen had already tallied the season’s high count with his report of 1,000 birds in Columbia County.”

2014 - “On that same date (2 April) numbers in Columbia County increased significantly with 750 birds tallied in the ephemeral flooded fields on Wangsness Road.”  Wangsness Road is four miles southwest of Goose Pond.

2017 - “Reported in 46 counties across the state this season...High count of 1,000 observed in Dane County at Island Lake WPA (David Johnson) on March 17, 2017, and in Jefferson County at Hope Lake (Aaron Stutz) on March 12, 2017.”

2018 - “Reported in 36 counties across the state this season...High count of 2,600 observed in Columbia County (Ted Keyel) on 17 March.”

2020 - (From WisBird) “More large numbers of White-fronted Geese were seen in several Columbia County ponds totaling about 3,000 - 4,000.

Photo by Arlene Koziol

It is clear that white-fronted geese are gaining ground in Wisconsin, particularly Columbia County, but why is their migration shifting? The first reason is increasing populations. White-front numbers have been on a steady rise for decades. As more individuals inhabit a region, they tend to spread out to reduce competitive pressures related to food resources. The second reason probably has to do with a change in their wintering grounds. Geese love rice. Texas was the undisputed rice center of the United States until the 1970s. Around that time, drought and global competition reduced the amount of rice grown in Texas. Mississippi Alluvial Valley states like Arkansas were able to capitalize on this change by converting row crops like corn and beans into rice fields where they could utilize their wetter climate and more abundant water resources. White-fronted geese seem to have shifted both their primary wintering grounds and spring migration routes much farther to the east in step with agricultural changes.

The winter population moved northeast and large numbers now winter south of Wisconsin so when they move north, they find Wisconsin including Columbia County with a large acreage of open water and abundant picked cornfields to feed in. Similar to other long-lived waterfowl species, it is likely that they remember ideal habitats and return to those local areas in subsequent years.

Graphic shows changes in winter distribution of greater white-fronted geese between 1975-2015. Graphic provided by Ducks Unlimited

Record Numbers at Goose Pond

The first time white-fronted geese were seen at Goose Pond was on March 26, 1978 by Laura Erickson. On March 22nd, 1980, Mark and Sue counted six individuals and Randy Hoffman spotted two more. The high counts for each decade at Goose Pond are 50 in the 1980’s, 10 in the 1990s, 50 in the 2000s, and 1,850 in the 2010s. The record has already been broken twice during this 2020 spring migration. Calla Norris and I counted 1,972 white-fronts on March 16, and Tom and Wendy Schultz counted 2,200 just five days later. According to past records, we’re at peak migration time for white-fronts here at Goose Pond. We encourage you to visit and view these charismatic creatures before their numbers dwindle significantly by mid-April.  If you can’t make it in person, check out Arlene Koziol’s wonderful collection of Goose Pond photos taken this week.

A lot of greater white-fronted geese at Goose Pond! Photo by Arlene Koziol

Additional Fun Facts

1. White-fronts often mob terrestrial predators by advancing on a predator as a threatening flock unless they are undergoing wing molt.

2. A high degree of natal philopatry and tendency to pair with genetically similar mates means there is strong likelihood of population structuring and the existence of unique genotypes. It is important to identify and protect these distinct groups. 

3. The oldest recorded greater white-fronted goose was at least 25 years, 6 months old when it was found in Louisiana in 1998. It had been banded in Nunavut in 1975.  A female in captivity lived to be a staggering 46 or 47 years old!

Written by Graham Steinhauer, Goose Pond Sanctuary land steward

Song Sparrow

First off, happy World Sparrow Day! Did you know such a day exists? Well, surprise, now you do! This international day of sparrow appreciation was originally designed to raise awareness of the population declines of the house sparrow (it’s true, many places on Earth are seeing significant declines). While the house sparrow is an introduced species in our part of the world, we can still appreciate and work to conserve our many native sparrow species, including but not limited to the delightful Song Sparrow. Read on!

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In the theater of evolution, Darwin’s finches and Hawaii’s honeycreepers arise as the preeminent examples of adaptive radiation. These island lineages, shaped through natural selection, have undergone intense speciation. 

On the Galápagos Islands, James Smith worked with Peter and Rosemary Grant to band and track the life history of the finches on the islands. The insights from work in the Galápagos have made incredible contributions to evolutionary biology. Years later, Smith would conduct a similar study as he and armies of others have banded song sparrows on Mandarte Island in British Colombia. 

Mandarte Island, BC, Canada. Photo courtesy of mandarte-island.weebly.com

All of this interesting research is built on the work of Margaret Morse Nice, who banded song sparrows in her backyard in Ohio starting in the 1930’s, changing the study of birds forever. Although she was not a classically trained biologist, Nice became a prolific researcher and published over 250 papers on birds in her lifetime. Banding the sparrows allowed her to study individual life histories, and learn about the intricacies of sparrow ecology. 

Today, we will look at the song sparrow and its fascinating life history, the whims of selective pressures, and the dynamic processes of an island population. 

Song sparrow. Photo courtesy of mandarte-island.weebly.com

The song sparrow is one of the most polymorphic species of birds in North America, though genetic evidence suggests that geographic subspecies are more connected than initially thought. The song sparrows on Mandarte Island are year-round residents of the rocky island, which is about six hectares. The habitats on Mandarte include sea island scrub, grassland, and open cliffs. Most song sparrows breed among the scrub, and prime territories are established in these areas. Since the 1960’s, the song sparrows on Mandarte Island have been studied in depth almost annually, and researchers summering on the island have many publications on these birds and even a book, published in 2006, Conservation and Biology of Small Populations: The Song Sparrows of Mandarte Island, where much of this information comes from.

Breeding can begin as early as March, and researchers on Mandarte have found pronounced effects of breeding date on the resulting number of fledglings. The earlier a pair breeds, the more offspring that will survive to fledgling. Moreover, the age of the parent causes significant changes in the total number of offspring, with both males and females peaking in reproductive success at age 3, displaying a bell curve distribution. 

Another ingredient of song sparrow life history on Mandarte is their density dependent reproduction. When the population is high, the juvenile survival is very low, and vice versa. Thus, during population crashes on the island due to weather or other unknown causes, the population quickly recovered with high fecundity while population highs saw the likely effects of competition acting on the birds. 

Baked into those population crashes are the effects of inbreeding, and researchers found pronounced effects from inbreeding. Reproductive success declined with higher coefficients of inbreeding, and in a trial of song sparrows experimentally injected with a parasite, those with a lineage of inbreeding exhibited a lesser immune response than heterozygous song sparrows. Overall, the birds resulting from inbreeding were less fit than other birds on Mandarte.

Banded song sparrow. Photo courtesy of mandarte-island.weebly.com

Numbers of females on the islands fluctuated wildly from 4 during the population crash of 1989, to over 70 1986. During these population crashes, it might have been expected that high inbreeding and low population could lead to the extinction of the song sparrows on Mandarte, but this was not the case. There was one effect sprinkled in that helped to save the song sparrow: immigration. On average, 2.8 song sparrows immigrate to Mandarte each year. While a small number, during population crashes, these immigrants bolstered the gene pool of Mandarte song sparrows and contributed to a population rebound. However, sparrows since the early 1990’s have seen less vigorous rebounds after population crashes, which may be a result of decreased immigration—the island only averaged .7 immigrant sparrows per year from 1993-2002.

Another interesting variable began sneaking its way onto Mandarte Island in the 1960’s: brown-headed cowbirds. This brood parasite lays its eggs in another bird’s nest, where the resident bird will often raise the outsized cowbird young. Cowbirds are migratory, and typically arrive on Mandarte after song sparrows start breeding. The proportion of nests parsitized is low when cowbirds first arrive but steadily increases into June and July, when over half of all nests are parasitized. With a high population of sparrows, the cowbirds found plenty of nests to parasitize, thus cowbird eggs correlated with the number of breeding females. In a similar vein, the proportion of failed nests also increased with a higher female population, and reached almost 50% of nests failing when there were over 70 females on the island. Overall cowbirds depressed population size and increased the likelihood of extinction on the island. 

Perhaps the most obvious thing to study in the song sparrow resides in its name, the song. Song sparrows exhibit variation in song length, and while females do sing in early spring during the establishment of territories, males dominate singing during the breeding months. As a male’s song repertoire increases, his probability of mating increases and his number of offspring increases. One of the more pronounced effects of inbreeding in song sparrows is the effect of inbreeding on song repertoire; males with higher coefficients of inbreeding showed simpler songs. 

Jonathan Weiner, in his book The Beak of the Finch, terrifically summarizes the work on Mandarte:

Summed over years, the effects of natural selection were invisible. But at each stage of their lives and each year of their lives the sparrows on that little island [Mandarte] had been “daily and hourly scrutinized” by the hand of nautral selection, much as Darwin had imagined, only in fast motion. The population on Mandarte is still being pushed every year…What seemed most striking to Dolph [a Mandarte researcher] as he studied the selection of events hidden in Smith’s data was the boring uniformity of Smith’s birds. Compared with Darwin’s finches, the sparrows of Mandarte might have been turned out by a cookie cutter. They showed only the very slightest of variations from one bird to the next in length of beak and length of tarsus... Yet even these varitaions, trivial as they seemed, had helped to decide who lived and who died. “That is pretty amazing to me!” Dolph says. It means populations don’t need to be excessively variable in order to experience natural selection. 

“Selection doesn’t happen just in the Galápagos,” Dolph concludes. “It happens in your backyard. “

Song sparrow living up to its name at Faville Grove Sanctuary. Photo by Drew Harry

From Margaret Nice’s backyard, to Mandarte Island, and even back here at Faville Grove, the song sparrow shows the tremendous variation and selective pressures present in nature, and what a remarkable view we have of these processes in one of our most common birds.

Written by Drew Harry, Faville Grove Sanctuary land steward

Snowy owls: Update on Columbia & Welcome to Fond du Lac

Columbia, the snowy owl, looks at the camera with her sharp, yellow eyes. Photo by Monica Hall

Update on “Columbia”

You can learn more about her by checking out her first Friday Feathered Feature. https://madisonaudubon.org/fff/2020/1/31/we-named-her-columbia

Scott Weidensaul’s March 1st Project SNOWstorm blog post is titled Zugunruhe to You, Too! https://www.projectsnowstorm.org/posts/zugunruhe-to-you-too/

“Ornithologists use the German term, zugunruhe — which translates to “migratory restlessness” — to describe this kind of growing itch that migrants feel as the seasons change. It’s brought on by hormonal changes triggered by both the bird’s internal circadian rhythms and the changing day length. Often it’s a strong wind from the right direction — southerly, in this case — that prompts an exploratory flight…” Four snowy owls with transmitters in the Dakotas and Saskatchewan exhibited zugunruhe the last week of February.  Scott wrote, “There’s been less evidence of zugunruhe in the owls farther east. In Wisconsin, Columbia has been tracing a very distinct movement pattern northeast of Morrisonville, a narrow, 7.5-mile (12-km) long path anchored at one end by the farmland and a sand quarry near Audubon’s Goose Pond Sanctuary, and at the other what must be a highly productive field for hunting just east of a large housing development.”

Columbia did not exhibit any zugunruhe until March 8th. At sunset she said goodbye to her new friends and headed north. She was flying at 30 miles per hour on southerly 12 mile per hour winds when she passed South Leeds. At one location she was clocked at 41 miles per hour.

A path marks Columbia’s northward journey since March 8.

Columbia would make frequent stops, with her first at the French Creek North State Natural Area in southern Marquette County.  She then headed over John Muir County Park (this location was on her bucket list), and ended up that morning just south of the Plainfield Tunnel Channel Lakes State Natural Area in Waushara County, 62 miles from her start 12 hours before.  She roosted and hunted in irrigated crop fields until 9:00 p.m. on the 10th. Then she headed north and northwest for a 46-mile flight ending up at the George Mead State Wildlife Area, northwest of Stevens Point where she stayed for one day before again moving northwest on a 72 mile flight ending up at a open bog in Sawyer County. Could she be taking a northwest direction to avoid flying over Lake Superior?

Fond du Lac, the snowy owl. Photo by Richard Armstrong

Introduction to “Fond du Lac”

Catching another owl was a partnership effort with Fond du Lac County Audubon Society who took the lead by paying for a new transmitter. Unfortunately no one from the organization was able to join us for the trapping effort. It was amazing to be able to catch three snowy owls.   Thanks to Angel Clark, Suzanne Bahls and Scott for their articles on the experience.

The Clark and Bahls family searched for owls on Saturday afternoon and located seven snowy owls! 

From a participant:

“On Saturday evening, February 22, 2020, my husband, Pat, informed me we should take our son Ben, to Norton’s Supper Club, on Green Lake, for his 25th birthday. Pat, then mentioned we need to leave a little early to search for snowy owls on the Mackford Prairie. He called his mission, "Operation Snow Storm.” I have never seen a snowy owl in the wild, so I wasn't quite sure what to look for. I thought this was another one of his wild goose chases searching for rare birds with his Madison Audubon buddies. It also makes me nervous when he's driving and looking through binoculars, so I sat in the backseat thinking I would be safer there. 

To our surprise we found one!... A female snowy owl was peached on a snowbank. However, she didn't stay on the snowbank for very long. She started to fly south-east and we followed her. It was hard to see her with the naked eye as she flew further and further away… She finally landed again in a snow covered field near a fence line. I also would like to mention, that this is truly like trying to find a needle in a haystack with all the snow and the owl basically being all white. But we did it! And boy, were we proud of ourselves! My husband, Pat, was so excited he called Mark Martin to give him his news report... "Hi, Mark. This is Pat. We spotted a snowy owl south-east on Lake Emily Road," I could hear Mark's voice on the other end. Mark said, "That's great Pat, now find another!" I chuckled to myself. It reminded me of a school child getting a good mark on a paper, and the teacher saying, now do it again on your next paper! 

The second spotting was on a telephone pole on the corner of Hickory Road, and Highway A. It was another female snowy owl. We were all in complete awe of this magnificent creature. It seemed as if this particular bird enjoyed the attention and wanted us to take her picture. We took many pictures with our mere camera phones. Then she must have spotted something edible on the ground across Highway A. It took off, swooped down just when there was an oncoming car! I thought my husband was going to jump out of his seat! He screamed, "Oh no, don't get hit by that car!" It did not. The owl made it safely to the other side, and came back to where it was originally peached. However, that seemed like it was very dangerous for the bird. Now I can see that these magnificent creatures need safer places to be. Better places for them to perch and find food. 

...From this experience, I have a whole new appreciation for these volunteers and scientists. Now, future generations will be able to experience what we did! Thank you, Project SnowStorm for all your hard work and dedication!”

-Sincerely, Angel Clark

Nine people met on Sunday (February 23) afternoon in Green Lake County east of Lake Maria to catch as many snowy owls as possible. Volunteers included Richard Armstrong, J D Arnston, Mark and Pat Clark from Madison Audubon, Jeff and Suzanne Bahls, and Rick Vant Hoff from the Horicon Marsh Bird Club, and Gene Jacobs and Brad Zinda from Linwood Springs.   

From a participant:

“My snowy owl obsession started about thirteen years ago when I went on a “first date” with Jeff Bahls. He took me to see one on highway 49 at Horicon National Wildlife Refuge. Every winter since, I have looked forward to their visits in our neck of the woods. When Jeff and I got married a few years back, we had a small, simple ceremony with our kids and celebrated afterwards with a snowy owl cake!  Therefore, a few weeks ago, when Mark Martin contacted Jeff about locating a Snowy Owl to be tagged for tracking, thoughts of actually getting to see one up close was like a dream! 

Jeff and I headed over to where we had seen one earlier... off a lightly traveled county road. When we got there, it had relocated to the other side of the road and further away. Gene thought it was still close enough, so he set the trap near the road and we watched… and waited. This owl did not budge. We watched him cough up a pellet and we thought, well, he must be hungry now... Mark Martin, who had been watching with us decided to take a little drive around and see if there were any other Snowies in the area. He found one sitting on a pole on the next road over. We could actually see it from where we were sitting. The problem was the road the second owl was on is a busy road. Mark talked to the landowner and got permission to set a trap on  the ground away from the road. It was decided to take a chance on the second owl. 

We picked up our trap and drove over to the second location. Brad took the trap and set it within sight of the second owl. We watched and waited again. About ten minutes later, the owl hopped off the pole and flew to the trap. She landed on top of it and then hopped off. She did not get tangled in the fishing line that was used to trap her. She sat a few feet from the trap and looked at it for a few minutes, then walked back to it and jumped on it a couple times, but still did not get tangled in the line. She then flew off about a hundred yards. Our hearts sank. Brad walked to the trap and re-adjusted the fishing line, and came back to the truck. We watched and waited again...  Several minutes later she took off flying toward the trap and finally got snagged in the line. Jeff and Brad jumped out of the truck and ran to the trap and went right to work untangling the owl. We got her!

We assisted Gene Jacobs and Brad Zinda in any way we could. During those few hours we caught three adult female Snowy Owls. Two were measured, banded and released back where they were caught. The third snowy was processed and Gene attached a GPS transmitter so Project SNOWstorm biologists can track her movements. It was amazing to witness first-hand the wings, beaks and talons of these gorgeous birds, and to see and work with the people from Madison Audubon and Linwood Springs Research Station. Reflecting on the events of that night still seems like a dream. It was an experience I will dream about for many years to come.”

-Suzanne Bahls

Fond du Lac stayed close to where she was released until March 7 when she moved a few miles north, just south of Green Lake. Her last cell phone was from that area on March 10th. We look forward to seeing her migration northward. 

Find more information on the capture and release of three snowy owls at the Project SnowStorm on Scott’s  blog post titled Fond du lac, and the Owl-fecta.

We hope that the owls enjoyed their visits to southern Wisconsin.  We also wish them safe travels to the land of the midnight sun and hope they return to southern Wisconsin next winter for another vacation.

Thanks to everyone who donated funds for the transmitters, to Gene and Brad from Linwood Springs for trapping and processing the owls, and to the volunteers who reported sightings, assisted with locating owls, taking photographs, trapping, and processing the birds.  We hope you follow their journey north.  

Written by Mark Martin and Sue Foote-Martin, Goose Pond Sanctuary resident managers, and Graham Steinhauer, land steward

Breeding Bird Distributions

Bird distributions are not random. Across the state, one notices that loons are a distinctly northern Wisconsin species, or that yellow-bellied sapsuckers occur over the northern half of the state, while also extending into western Wisconsin’s Driftless Area. Perhaps even locally, one notices an abundance of Canada Geese breeding around urban ponds, where park lawns and predator-free expanses make happy geese. 

Color codes for breeding status.

Of peculiar interest to me, at Faville Grove Sanctuary, is the presence and absence of certain bird species. Today, we will observe the biogeography of certain bird species in Wisconsin, based on maps pulled from eBird data on the second Wisconsin Breeding Bird Atlas. To the right, you’ll see the different categories of breeding, based on quantitative observations gathered during Wisconsin’s recently completed five year long Breeding Bird Atlas.

The striking feature of many of the maps that follow is the absence of breeding birds in the Faville Grove Area. From roughly Lake Koshkonong to south, Madison to the west, Horicon Marsh to the north, and the Kettle Moraine to the east, one notices distinct range gaps in many of these bird species. The absence of certain species in this region speaks to the necessity of a landscape-scale habitat project, and the presence of many of these birds at Faville Grove is a testament to the habitat restoration conducted here. 

A fun game is to try and guess the species based on the map.

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First, we will analyze the upland sandpiper. Formerly abundant at Faville Grove, the bird used to nest with up to one pair every 1.5 acres, though the birds have not been seen in decades. Art Hawkins, one of Aldo Leopold’s graduate students, published an important paper on the ecology of the Upland Sandpiper at Faville Grove. 

The bird occurs south, west, east, and north of Faville Grove, though in very small numbers. South of Baraboo you can see a block of confirmations from the Sauk Prairie Recreation Area, which includes large acres of new prairie restorations. With new land acquisitions at Faville Grove forming large contiguous blocks of prairie, we eagerly await a possible return of the upland sandpiper.

Upland sandpiper, photo by Vitalii Khustochka, FCC

Upland Sandpiper breeding range in southern Wisconsin, conspicuously absent from the circled area. Star indicates Faville Grove Sanctuary

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The short-eared owl was a common breeding species at Faville Grove up until Aldo Leopold’s time in the 1930’s and 40’s. The bird has returned with increasing grassland acreage, overwintering on a diet of meadow voles from the prairie. There is potential for breeding pairs with expanded contiguous habitat.

Short-eared owl, photo by Mick Thompson

The light purple block west of the I-94 marker is the atlas block that contains Faville Grove Sanctuary

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A charismatic and bold bird, the red-headed woodpecker is a relatively common breeder in southern Wisconsin, though remains uncommon in the Faville Grove region. Oak trees and dead snags are critical to keep this species over summer, and a breeding pair has occupied this exact habitat at Hope Lake Bog (an outlying Madison Audubon property) for a number of years. Consistent sightings in the savanna of the Lake Mills Ledge indicate that the canopy thinning has improved habitat for this species.

Red-headed woodpeckers, photo by Kelly Colgan Azar

Red-headed woodpecker breeding locations.

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A unique warbler with a warm buzzy song, the blue-winged warbler has been expanding northward in Wisconsin since the turn of the twentieth century. Between the first and second Breeding Bird Atlas, breeding pairs have moved even further north into the northwestern and northeastern parts of the state. Yet, the bird is strikingly absent from the Faville Grove Area. One pair was confirmed during the Atlas at the Waterloo Wildlife Area, to the north, where I have seen and heard dozens of the birds during migration. Nesting in shrubby areas and along forest edge, why the birds remain absent from Faville Grove remains a mystery.

Blue-winged warbler, photo by Kelly Colgan Azar

Breeding map for blue-winged warblers in southeastern Wisconsin.

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A declining forest bird, the ovenbird lacks necessary habitat at Faville Grove. A ground nester, the ovenbird needs extensive forest tracts.  From the map, we can almost identify the entire Kettle Moraine from southwest to northeast. It seems that outside of the Kettle Moraine, little suitable habitat exists. This is a common plight of many forest birds—the southeast glacial plains ecological landscape is about 4.9 million acres, with almost 3 million acres in agriculture. A mere 392,000 acres of the entire landscape is upland forest, and the only large blocks of forest are located in the Kettle Moraine, where you can also find ovenbirds.

Ovenbird, photo by Kelly Colgan Azar

Breeding map for ovenbirds in southeastern Wisconsin.

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Found in young forests and shrublands, the mourning warbler occurs for the most part north of Faville Grove, but does breed in the Southern Kettle Moraine State Forest. Savanna restorations may be important breeding areas for this bird, though the overall extensive forest cover of northern Wisconsin is preferred.

Mourning warbler, photo by Tom Benson

Breeding map for mourning warblers in southeastern Wisconsin.

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Here, we see a grassland species with an affinity for forb-rich prairies and high diversity. Faville Grove’s high diversity prairie restorations should provide excellent habitat for the grasshopper sparrow, and one singing bird this past summer could be an indication of a bright future at Faville Grove. Breeding pairs in this area would be an important population boost for the region.

Grasshopper sparrow, photo by Kelly Colgan Azar

Breeding map for grasshopper sparrows in southeastern Wisconsin.

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Finally, we can locate Faville Grove’s block precisely on this map, where a black square west of the I-94 marker confirms the breeding of Henslow’s sparrows at Faville Grove. Unburned prairie seems a necessity for the Henslow’s sparrow, and a shifting patchwork of burns has provided excellent habitat for an increasing population of this state-threatened bird at Faville Grove.

Henslow’s sparrow, photo by JanetandPhil, FCC

Breeding map for Henslow’s sparrow in southeastern Wisconsin.

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It could be that the geographic gap in species’ ranges is an artifact of the sampling—located between high population centers in Madison and Milwaukee, the gap apparent in many ranges could just lack sufficient birding. However, the map below shows many areas between Madison and Milwaukee with over 100 checklists, and an overall good coverage of the entirety of southeast Wisconsin.

Map of sampling effort in southeastern Wisconsin.

A confluence of factors merges to produce these range gaps in many species. As stated earlier, only 8% of the southeast glacial plains is upland forest. Of the entire landscape, only 4% is publicly owned. Small slivers of habitat tend to hold fewer birds than large blocks. Thus, on a landscape wanting for many bird species, a landscape-scale habitat restoration project like Faville Grove can fill the gap.

Written by Drew Harry, Faville Grove Sanctuary land steward

Northern Shrike

One of the most striking birds of winter resides on the shrubby grasslands and savannas of southern Wisconsin. In this habitat, you can find wild plum, hawthorn, black locust, or barbed wire. The common link is spikes, thorns, or barbs. In winter in Wisconsin, if you search these spiny spots, the unsettling link might be impaled microtine voles. The uninitiated might look to the sky, wondering if a hawk dropped its prey randomly onto a plum bush. The answer comes from the sky, though not from a raptor species dropping the vole. Instead, you are on the wintering range of the northern shrike, a passerine, or songbird, (the only passerine in Wisconsin to regularly eat vertebrates) which actively stuck the vole in its place. The purpose of this act is to consume prey efficiently over the course of the winter. At any point, a northern shrike will cache, or save, up to seven prey items.

An impaled vole is cached for a northern shrike’s next meal. Photo by Drew Harry

Impaled voles, mice, and other small mammals are common indicators that you are on shrike territory, which can range from 500-1,000 acres over winter. Another interesting prey item are species of its own order—songbirds! Shrikes will consume birds like horned larks, dark-eyed juncos, house sparrows, American robins, red-winged blackbirds, pine grosbeaks, and red crossbills. Many of these birds are much bigger or quicker than the shrike, and thus shrikes will take other birds in surprise attacks. In a twisted move, shrikes will even mimic the calls of other songbirds to lure them into area where they ambush an unsuspecting sparrow.

In February, I often start getting concerned about the house sparrows looming around bluebird boxes around my house, although this year they have been noticeably absent. The reason might be a shrike that I’ve spotted a few times around the house. Shrikes typically sit for 1-2 minutes on the tops of trees, perched, and waiting to strike. A week ago, I was able to get some decent pictures through my window of an immature northern shrike as it moved from bur oak tree to pear tree and again back to the bur oak trees scattered about the yard; each time sitting for 1-2 minutes and allowing me to capture a few shots.

A northern shrike is spotted at the top of this oak tree at Faville Grove Sanctuary. Photo by Drew Harry

A northern shrike scouts the landscape to make its next move. Photo by Drew Harry

A northern shrike sits perched on the tip-top of a tree, giving nearby humans a minute to get a good look. Photo by Drew Harry

The immature shrike shows gray barring on its chest, a white eye-ring, and like adult shrikes has a light underside with a blue-gray top and a narrow black mask across its eye. The hooked bill is also diagnostic.

Barring, eye ring, and mask are all visible in this shot of a northern shrike. Photo by Drew Harry

For me, the most fascinating part about the northern shrike is its winter diet. While impaled small mammals steal the show, over 60% of an individual bird’s winter diet is composed of arthropods. A study in Idaho analyzed the regurgitated pellets of northern shrikes and found an average of 2.8 prey items per pellet. Overall, 33 species were identified in pellets for a wide and diverse sampling of food. To follow a shrike in winter is to understand the surprising breadth of prey items active through winter.

You might ask, aren’t arthropods dormant during winter? For the most part, yes. However, many species will stay active, and on slightly warmer days the south-facing slopes, rock outcrops, or other exposed areas can heat more quickly than other areas and cause some invertebrates to become active. In southwestern Idaho, rimrock areas are preferred by shrikes presumably due to the higher arthropod activity on these exposed rock areas.

Faville Grove has exposed rock—1.8 billion year old quartzite—perhaps a source of arthropods for the local shrike? Each winter we often see a shrike in the western part of the Sanctuary, hanging out in the tops of tamarack trees in the Diedrich-Alexander Wildlife Area along North Shore Road. You might find a shrike anywhere within Faville Grove Sanctuary, but your best bet is to keep looking at the tops of trees, or look for indirect evidence on spiny trees and bushes.

Written by Drew Harry, Faville Grove Sanctuary land steward

Cover photo by Eric Ellingson