Two secretive resident raptors can be found across the state’s more remote, contiguous, and mature forest blocks. Wisconsin lies at the southern edge of the continental range for the Northern Goshawk, and the northwestern continental range limit for Red-shouldered Hawk. Each is a Species of Greatest Conservation Need (SGCN), with the Red-shouldered Hawk being listed as state Threatened. Both are among the earliest breeders in the state. The Atlas will play a key role in understanding the current status of these priority species. This article outlines tips and strategies to improve your chances of finding them.
Northern Goshawk
Photo by Brian Collins
Some Wisconsin birders have likely experienced the adrenaline rush of dodging an angry goshawk defending its nesting territory. They are easily among the most aggressive birds we have in the state near their nest, and anyone trying to confirm a nest should use extreme caution! They should be searched for in the northern two-thirds of the state where large blocks of forest exist with a core area of mature forest (>30 acres) for nesting. Because of their secretive nature, a long walk (0.5 – 1.0 mi.) from the nearest road or trail is typically required to locate a nesting territory. Broadcast call surveys work well at detecting their presence in spring and should be performed from 1 March to 15 May.
Region: Northern half of Wisconsin but they are much more common in the north woods than in the central forest. The eBird Range Map also clearly shows the higher density in the northern third of the state.
WBBA I range map
Time of Year: Most nesting Northern Goshawks are year-round residents, but those that migrate arrive in Wisconsin in late-February to early-April. Courtship can occur up to two months before egg-laying, with nesting initiated by mid- to late-April. Fledglings standing on the nest or “branching” near the nest can be visible by early- to mid-June. Breeding codes may be recorded from April (Pair in Suitable Habitat, Territory defense, Occupied Nest) into late July when fledged young are still near the nest and dependent upon their parents for food.
Breeding Guideline Bar Chart: (Full chart is on Atlas handbook webpage)
Time of Day: Northern Goshawks are diurnal raptors (active throughout the daytime hours), with the best time to target broadcast call surveys being from sunrise to late morning, when winds are calm and calls can be heard clearly.
Focal Habitat: The best nesting habitat areas are large blocks of closed canopy, mature, northern mesic forest stands. These areas are dominated by deciduous tree species (sugar maple, yellow birch, basswood, and aspen) but typically include a conifer component, with hemlock and white pine commonly encountered. Deciduous trees are often selected for nest placement, with yellow birch and aspen being favorites. Nesting territories in central Wisconsin, where the species is much less common, also include pine plantations and white pine – red maple swamps.
Special Methods: Broadcast surveys utilizing conspecific calls during the breeding season (1 March – 15 May) are an effective way to boost detections of this secretive species. Whenever using song playback, refer to our guidelines in the Atlas handbook, including: limit the length and frequency of use, avoid heavily birded areas, and turn off playback immediately once a species has been detected. An added advantage is increased efficiency in locating nests prior to leaf-out during this time. It is important to note that nesting territories are often in remote locations and a long walk from the road. For this reason, roadside broadcast surveys are not a recommended survey technique. Early mornings until noon are the best for detections because of low wind conditions (allowing broadcast calls to carry farther) and synchronization with peak foraging activity periods for adults. Surveys should not be conducted during rain, snow, or temperatures below freezing, to avoid jeopardizing nest success.
Code Guidance: When adults are heard giving their alarm call (ascending “kak-kak-kak-kak”) during the breeding season (see breeding guidelines bar chart) a nest is likely nearby. Persistent alarm calls could warrant A for Agitated Behavior, and an aggressive flyby could warrant T for Territory Defense or even DD for aggressive divebombing (see our article explaining these 3 codes). Active nests are distinctive in their size (20 – 30” in diameter) and location in the tree, with the nest usually located in a main fork near the trunk and typically 40 – 60’ up. Conifer (pine or hemlock) boughs are frequently added to active nests; when these or down feathers are visible on the nest, or whitewash is seen below the nest, ON code should be used. It is important to note that nesting pairs may have 1 – 3 alternate or old nests within the territory. If the previous clues are not seen, use N (visiting probable nest site).
Due to sensitivity of nesting sites, please report any potentially breeding Northern Goshawks to eBird on separate checklists and immediately HIDE all reports. Send any observations of nests or aggressive adults to Richard.Staffen@wisconsin.gov. The hide checklist function appears immediately after you submit a checklist, and if you check this box as soon as you submit a checklist, it should immediately remove the report from public view.
Other Species: Other early season associates can be given breeding codes during this time. Broad-winged Hawks are returning in late-April and May and are often heard calling in nearby habitats. Some mature stands may have Red-shouldered Hawk co-existing nearby. Common Ravens and American Crows are nesting and may be found in close proximity. Ruffed Grouse are frequently drumming, Wild Turkeys are gobbling, snipe are “winnowing”, and woodpeckers are commonly heard drumming.
Confusing Species: Northern Goshawks are our largest accipiter (long tail, short rounded wings for maneuverability) and have a distinctive blue-gray back and gray breast in adult plumage and a very prominent white eye-line in all plumages. As adults, they have occasionally been confused with the female Cooper’s Hawk, which is the closest accipiter in size. Cooper’s Hawks lack the white eye-line and have rust-colored barring on the breast. They are more easily confused during their immature plumage when both of these species have a brown back and pale breast with brown streaking. The white eye-line in the Northern Goshawk is again a prominent distinguishing feature along with larger, bulkier size and thicker brown streaking on the breast.
More Information on Northern Goshawk:
Wisconsin All-Bird Plan
All About Birds
Wisconsin DNR Species Guidance document
Birds of North America (subscription required)
Red-shouldered Hawk
Photo by James Limburg
Red-shouldered Hawk is more common than many realize in Wisconsin, but because they are located in somewhat remote and difficult-to-access interior forests they are rarely seen. They should be searched for throughout the state where large blocks of mature forest exists, especially in bottomlands associated with large- or moderate-sized rivers and streams. Broadcast call surveys work well at detecting their presence in spring, and should be performed from 15 March to 01 May. The Wisconsin Red-shouldered Hawk Survey was initiated through the Wisconsin Bird Conservation Initiative in 2010 and verified the validity of utilizing roadside playback call surveys to detect presence of birds while also showing the importance of large river floodplain forests for the species.
Region: Found statewide in Wisconsin, but they are fairly rare in the northern-most counties along Lake Superior and over to the Northern Highlands. The eBird Range Map also clearly shows the bird is now present throughout southcentral Wisconsin, where they were not detected in WBBA I, and in lower densities in the northern tier counties of the state.
WBBA I range map
Time of Year: Some southern-Wisconsin-nesting Red-shouldered Hawks are year-round residents, but most breeding individuals migrate out of the state for the winter months. They are short-distance migrants that return to Wisconsin in late-February to early-April, usually timed to coincide with the emergence of the eastern chipmunk, a key prey item. The courtship period lasts from early March through mid-April, and is when birds are most detectable, as they are actively defending territories and are very vocal. Once the incubation period begins in mid- to late-April, the female is more difficult to detect, as she may hunker down on the nest when approached or silently fly off and wait for the “intruder” to leave. During the nestling and fledgling period from late-May through June, active nests can be located and actively foraging adults are more detectable. Breeding codes may be recorded from April (Territory defense, Occupied Nest) into early-August before fledged young begin to leave their parents’ breeding territory.
Breeding Guideline Bar Chart: (Full chart is on Atlas handbook webpage)
Time of Day: Red-shouldered Hawks are diurnal raptors (active throughout the daytime hours), with the best time to target broadcast call surveys being from sunrise to late morning, when winds are calm and calls can be heard clearly. The adults are also most actively foraging during the morning hours.
Focal Habitat: The best nesting habitat areas are large blocks of closed canopy, mature forest, especially those that are associated with large- or moderate-sized river and stream systems or upland stands that are in close proximity to open wetlands. Floodplain forests are critical habitats for the species, and are dominated by deciduous tree species like silver maple, river birch, basswood, and swamp white oak; these are most commonly selected for nest placement. Upland forest types include both dry-mesic to mesic stands throughout the state. Red oak is often dominant in these stands, but they may also include maples, white pine, and American beech (in eastern portions of the state). Site suitability for Red-shouldered Hawk is dependent upon a few key features: the stands must be in close proximity to open wetlands or ephemeral ponds for foraging, and mature trees are present for placement of their nests.
Special Methods: Broadcast surveys utilizing conspecific calls during the breeding season (15 March – 1 May) are an effective way to boost detections of this secretive species. Whenever using song playback, refer to our guidelines in the Atlas handbook, including: limit the length and frequency of use, avoid heavily birded areas, and turn off playback immediately once a species has been detected. An added advantage to doing surveys this early in the season is the increased efficiency in locating nests before leaves are on the trees. Roadside broadcast call surveys have been widely utilized as a survey technique to detect presence. Early mornings until noon are the best for detections because of low wind conditions (allowing broadcast calls to carry farther) and synchronization with peak foraging activity periods for adults. When possible, follow up on positive responses or calling individuals by doing nest searches. To locate a nest, walk toward the direction of the response for 0.25 – 0.5 miles, then turn around and repeatedly walk parallel to the previous path at 25- to 35-meter intervals to cover the area of suitable habitat. Surveys should not be conducted during rain, snow, or temperatures below freezing, to avoid jeopardizing nest success.
Code Guidance: When adults are heard giving their alarm call (ascending “kee-ahh, kee-ahh, kee-ahh”) during the breeding season (see breeding guidelines bar chart), a nest is likely nearby, but should be coded as S for Singing Male. Active nests are distinctive in their size (18 – 30” in diameter) and location in the tree, with the nests usually located in a main fork near the trunk and typically 50 – 60’ or more up the tree. Nest trees are commonly deciduous species, but conifer (pine, hemlock) boughs are frequently added to active nests. When these or down feathers are visible on the nest, or whitewash is seen below the nest, the ON code should be used. It is important to note that nesting pairs may have 1 – 3 alternate or old nests within the territory; if the previous clues are not visible, use N (visiting probable nest site).
Other Species: Other early season associates such as Broad-winged Hawks, Wild Turkeys, Wilson’s snipe, woodpeckers, and American woodcock have been seen nesting or vocalizing in these habitats.
Confusing Species: Broad-winged Hawks are the most similar in plumage and also occur in similar forested habitats in or near wetlands. See our article with tips on distinguishing these two species. Broad-wingeds are smaller and have brown streaking on their breast and wider white bands on their tail as compared to the larger Red-shouldered Hawk, which has red or rusty barring and thinner white stripes on the tail. Red-tailed Hawks are slightly larger, generally occur in more open habitats, and adults have a solid orange tail, and prominent dark breastband.
More Information on Red-shouldered Hawk:
Wisconsin All-Bird Plan
All About Birds
Wisconsin DNR Species Guidance document
Birds of North America (subscription required)