Just about every birder in the Midwest loves the arrival of spring migrants. During these months, no bird is more highly anticipated than warblers. These colorful and fast moving birds captivate the birding community for at least a month each year as everyone tries to gorge themselves on viewing as many of them as they can for the fleeting time they are here. While most species of warblers are easy to find during migration, there are some that are extremely rare. Some of these species are reported annually while others are only seen once or twice in a ten year span. Either way, finding one of these warblers can make even the most routine day birding into an instantly memorable day.

Black-Throated Gray Warbler

Extremely Rare

The Black-throated Gray warbler is aptly named for its black throat and dusky gray back is an extreme rarity in the Midwest with few individuals straying east of Colorado. At first glance, this species could be mistaken for a Black and White Warbler or a Blackpoll Warbler. Upon closer inspection, the Black-throated Gray Warbler has a distinctive yellow marking on the face near the bill. This species has been seen twice in Wisconsin since 2010 with all sightings occurring in May in either Dane or Ozaukee County. Black-throated Gray Warblers have also been seen in Minneapolis and north of Chicago. The most likely way to find one is to get out during May migration and check each black and white colored warbler very carefully.

Townsend’s Warbler

Extremely Rare

The Townsend’s Warbler is another bird of Western North America that rarely strays out of its normal range. Their back is greenish yellow, their wings are black with two white wing bars, and their chest is yellow with black streaks. They have a dark cap, black throat, and distinctive yellow crescent shaped marking on the side of the face. Upon first glance they look similar to the much more common Black-throated Green Warbler, but with a closer look the differences are noticeable. Since 2010 there have been three instances of Townsend’s Warblers in Wisconsin. One bird seen at Pheasant Branch in Madison in May of 2014, one bird visiting a feeder in Kewaunee in December of 2016, and one interesting report of a bird landing on a boat 10 miles off-shore near Manitowoc in September of 2010. There seems to be very little pattern to the appearance of Townsend’s Warblers in our state but they do visit bird feeders so it’s possible that one could show up at a birders residence.

Prairie Warbler

Rare but Annual

The normal range of Prairie Warblers spans from the eastern Central America in winter all the way up to the Atlantic coast of Maine. Their visits to Wisconsin are few and far between with roughly one or two sightings each year. Males have a bright yellow underside with bold black streaking on the flanks and gray wings with a chestnut brown patch on the upper part of the back. They have a black semicircle under the eye. Females look similar but with more muted colors and a more grayish head. Prairie Warblers are not uncommon in lower Midwestern states but in Wisconsin the best place to find them is in the southeastern counties along Lake Michigan. There was one reliable Prairie Warbler present for five years straight during May Wisconsin’s South Kettle Moraine State Forest, but that bird has since moved on.

Kirtland’s Warbler

Annual and Breeding

Kirtland’s Warblers have a dark gray back with black streaks. Their throat and underside is bright yellow and they have distinct white markings directly above and below the eye. Males have a dark marking between their eye and bill while females are more drab with darker speckling on their underside. While not the most extravagant species, they are one of the rarest warbler species in North America due to their incredibly stringent habitat requirements for nesting. They require Jack Pines around 5-6 feet tall and leave the area once the pines exceed 10-15 feet. These birds winter in the Caribbean and migrate primarily to Michigan in the spring with a population also breeding in Wisconsin. Since this species is sensitive, there is little information on ebird about where to find them in Wisconsin but they do show up from time to time along their migratory path as well as in their top secret breeding grounds.

Worm-Eating Warbler

Annual and Breeding

The range of the Worm-eating Warbler is similar to that of the Prairie Warbler from Central America up the east coast and breeding east of Texas. This species is easily distinguished from other warbler species by its large pinkish bill and black head stripes on an otherwise buffy bird. Worm-eating Warblers live in areas with steep slopes and dense understory. They can be found in various places resembling this habitat in Wisconsin including Milwaukee, Madison, along the Mississippi River, and Devil’s Lake State Park. When trying to find this species listen for their high pitched buzzing call which sounds similar to that of a Chipping Sparrow.

Honorable Mentions

Other than the five species mentioned above, there are a few other warbler species that can be hard to find but are all expected to be reported several times a year or that breed in known locations in Wisconsin. Here is a brief listing of these species:

Connecticut Warbler

Yellow-throated Warbler

Kentucky Warbler

Cerulean Warbler

These species are always nice to find. Especially if they are found away from their expected locations.

Final Thoughts

May is truly an exciting month for birders as millions of birds are on the move. With a bevy of different habitats in Wisconsin and rare species showing being reported across the state, who knows what bird might show up next. Hopefully, some of those reading this will have success finding one of these rare species in Wisconsin to make the month of May that more special.