Red-shouldered Hawk

Unlike other Virginia raptors, such as the Red-tailed Hawk (Buteo jamaicensis), Red-shouldered Hawks are often heard before they are seen. While moving through wet forests, this hawk utters a repetitive kee-aah-kee-aah-kee-aah. Red-shouldered Hawks have a diverse diet that includes insects, earth worms, frogs, snakes, small mammals, and occasionally small birds (Dykstra 2020). They are also faithful to their nesting sites, returning each year to the same territory, and often the same tree, to build their large stick nests.

Breeding Distribution

Red-shouldered Hawks occur throughout Virginia but are most likely to occur in the Piedmont and Coastal Plain regions (Figure 1). Their likelihood of occurring in a block increases with increasing amounts of forest edge habitat and grassland and shrubland habitat and decreases in blocks with more agricultural lands.

Because of model limitations, the Red-shouldered Hawk’s distribution the First Atlas and its change between the two Atlas periods could not be modeled (see Interpreting Species Account). For more information on its occurrence during the First Atlas, please see the Breeding Evidence section.

Figure 1: Red-shouldered Hawk breeding distribution based on probability of occurrence (Second Atlas, 2016–2020). This map indicates the probability that this species will occur in an Atlas block (an approximately 10 mi² [26 km²] survey unit) based on environmental (including habitat) factors and after adjusting for the probability of detection (variation in survey effort among blocks).

Breeding Evidence

Red-shouldered Hawks were confirmed breeders in 319 blocks and 91 counties and probable breeders in an additional 12 counties (Figure 2). Although substantially more breeding confirmations were observed during the Second Atlas than during the First Atlas, which is in line with its sizeable increase in population in the state at the same time (see Population Status), it important to note that considerably more survey effort also occurred during the Second Atlas (Figure 3).

The Red-shouldered Hawk’s habit of frequent, loud vocalizations near nest sites makes them fairly detectable. As such, the earliest breeding confirmation was an observation of adults carrying nesting material in early mid-January (Figure 4). The most frequently observed breeding behaviors were occupied nests (January 26 – July 5), nests with young (March 20 – July 8), and recently fledged young (April 14 – September 4).

For more general information on the breeding habits of this species, please refer to All About Birds.

Figure 2: Red-shouldered Hawk breeding observations from the Second Atlas (2016–2020). The colored boxes illustrate Atlas blocks (approximately 10 mi² [26 km²] survey units) where the species was detected. The colors show the highest breeding category recorded in a block. The numbers within the colors in the legend correspond to the number of blocks with that breeding evidence category.

Figure 3: Red-shouldered Hawk breeding observations from the First Atlas (1985–1989). The colored boxes illustrate Atlas blocks (approximately 10 mi² [26 km²] survey units) where the species was detected. The colors show the highest breeding category recorded in a block. The numbers within the colors in the legend correspond to the number of blocks with that breeding evidence category.

Figure 4: Red-shouldered Hawk phenology: confirmed breeding codes. This graph shows a timeline of confirmed breeding behaviors. Tick marks represent individual observations of the behavior.

Population Status

Red-shouldered Hawk relative abundance was estimated to be highest throughout large areas of the Piedmont and Coastal Plain regions (Figure 5). Low abundance levels were predicted throughout most of the Mountains and Valleys region, except the most southwestern area.

The total estimated Red-shouldered Hawk population in the state is approximately 117,000 individuals (with a range between 65,000 and 213,000). Based on the North American Breeding Bird Survey (BBS), the Red-shouldered Hawk population increased by a significant 4.72% annually from 1966-2022 in Virginia and by a significant 4.44% per year between Atlases (from 1987–2018) (Hostetler et al. 2023; Figure 6).

Figure 5: Red-shouldered Hawk relative abundance (Second Atlas, 2016–2020). This map indicates the predicted abundance of this species at a 0.4 mi² (1 km²) scale based on environmental (including habitat) factors. Abundance values are presented on a relative scale of low to high.

Figure 6: Red-shouldered Hawk population trend for Virginia as estimated by the North American Breeding Bird Survey. The vertical axis shows species abundance; the horizontal axis shows the year. The solid line indicates the estimated population trend; there is a 97.5% probability that the true population trend falls between the dashed lines. The shaded bars indicate the First and Second Atlas periods.

Conservation

In the eastern U.S., the Red-shouldered Hawk has a very large range, stretching from southern Texas to Minnesota in the west and Florida to Maine in the east (Dykstra et al. 2020). While not of conservation concern in Virginia, like many forms of wildlife, habitat loss is the greatest threat to Red-shouldered Hawks.

Interactive Map

The interactive map contains up to six Atlas layers (probability of occurrence for the First and Second Atlases, change in probability of occurrence between Atlases, breeding evidence for the First and Second Atlases, and abundance for the Second Atlas) that can be viewed one at a time. To view an Atlas map layer, mouse over the layer box in the upper left. County lines and physiographic regional boundaries (Mountains and Valleys, Piedmont, and Coastal Plain) can be turned on and off by checking or unchecking the box below the layer box. Within the map window, users can hover on a block to see its value for each layer and pan and zoom to see roads, towns, and other features of interest that are visible beneath a selected layer.

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References