Red-shouldered Hawks in Their Home-range

October 16-17, 2022 ~ I love seeing raptors. I’m tickled every time I see a Red-tailed Hawk, even though they are the most common hawk in the United States, and are literally everywhere. But, on each of these two days I was delighted to see Red-shouldered Hawks, Buteo lineatus, slightly smaller than the Red-tailed, and only half as common.

Red-shouldered Hawk range map, courtesy of All About Birds

A large portion of the population are year-round residents, and the northern-most birds that migrate are short-distance travelers, easing just far enough south to avoid the really cold winters. Red-shouldered Hawks are here along the upper Texas Gulf Coast all year.

The little “?” shown by All About Birds in the blue area indicates that Red-shouldered Hawks are occasionally seen in the blue region. The eBird observations map, also shown on All About Birds, confirms that the sightings in Mexico are very sparse.

Red-shouldered Hawk feathering the flaps for her landing
1/2500 sec. f/5.6 ISO 200
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR

Sunday, October 16^th was a hot and sticky day. As a group of us were walking around the shrinking Elm Lake at Brazos Bend State Park (BBSP), we looked across the water to see first a single Red-shouldered Hawk land high in a dead tree, and then a second hawk join him.

Balance is tricky on these long rickety spars
1/2500 sec. f/5.6 ISO 200
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR

The Red-shouldered Hawk has a generally russet appearance with dark brown-and-white checked wings and black-and-white striped tail. Their chest and belly are rufous with a subtle horizontal striped pattern. Their shoulders have the deep russet coloring of their back, though sometimes the shoulder is hidden by fluffed neck feathers.

There are 5 sub-species in the US… or maybe 4, or maybe only 3, depending upon who you ask. The most pronounced differences are between the elegans of California which is the most richly colored with dark russet head, the extimus of Florida which is the palest, with a mostly gray head, and the ones we saw, the lineatus, or alleni, or texanus. To make identification even more challenging, Red-shouldered hawks have hybridized with Gray Hawks (Buteo plagiatus), Red-tailed Hawks (Buteo jamaicensis) and Common Black Hawks (Buteogallus anthracinus), so may show mixed characteristics of each. Humph. Moving on.

Male (above) and female (below) rest in the bright sun
1/2500 sec. f/5.6 ISO 125
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR

The male and female have the same plumage, but as with most raptors, the female is about 20% larger than the male. So, I believe that the male is topmost on the branch, and the slightly heavier female is perched below. Their weight differences maximize their hunting success: the females being slower and stronger take the larger prey, while the males, more agile and faster take the smaller speedier prey.

Cool, calm and collected Red-shouldered Hawk
1/1000 sec. f/5.6 ISO 3200
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR

The next day, Monday the 17th, presented us with the first mild-temperature day in months. I celebrated the arrival of this little “cool front” by going back to BBSP, this time to walk around 40-acre Lake. The sky was overcast, and there was a nice breeze. Along the northeastern edge of the lake, I spotted this lovely Red-shouldered Hawk. Where the pair on Sunday had been roughly 350 feet away, this hawk was less than 50 feet away. He (or she) was watchful and calm, peering slowly left and right, but completely tolerant of my presence and the persistent clicking of my camera.

Red-shouldered Hawk waking up grumpy in the August heat
1/2500 sec. f/6.3 ISO 1250
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR

I recalled surprising a Red-shouldered Hawk on Hoot’s Hollow Trail as I walked underneath his branch in August. He had been just inside the edge of the forest along the west end of 40-acre Lake, only a few hundred feet from this new sighting, but I didn’t yet connect the dots.

Checking the undergrowth for prey
1/800 sec. f/5.6 ISO 2000
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR

Red-shouldered Hawks live at the intersection of two biomes, in deciduous or open conifer forests with standing water at the edge of riparian (river-side or lake-side) swamps and meadows. That perfectly describes the land in the park, and the locations where I saw these hawks. The spreading live oaks, pecans and hawthorns standing in or near the low flat swamps covered with only an inch or two of water provide the perfect habitat in which to hunt small mammals, reptiles and amphibians. Red-shouldered Hawks also sometimes take birds such as doves. And All About Birds notes that they sometimes team up with their natural enemy, the American Crow (which will eat eggs, and is common in BBSP), to drive away larger predators such as the Great Horned Owl.

Many raptors establish a “home-range” in which most of their hunting takes place. Their home-range is a very-roughly sketched circle centered on their nest. Detailed studies of Red-shouldered Hawks in Georgia, Wyoming, Wisconsin, New Jersey and California have established that their home-range is typically approximately 1.2km across, with at least 2km between nests, and that their range expands in the fall after raising their families, likely because their intensive hunting during spring and summer has depleted prey population in their original patch. For example, this is the map from a study conducted in Georgia in spring and summer 1997.

So… was this one of the same birds I had seen the day before?

Sneak attack!
1/800 sec. f/5.6 ISO 1600
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR

I know, another butt-shot. I came within a split second of deleting this image. But then I saw what the hawk had surely known all along. His mate had been positioned behind me, and with one ground-hugging stealthy swoop, flashed past just as I took this photo. While taking the shot, I had seen a momentary smudge, but didn’t realize what I’d captured until I downloaded and processed my photos.  At my slower rate of 3 frames per second, only one frame showed the silent fly-by.

Now the penny dropped. On two consecutive days, I had seen a pair of Red-shouldered Hawks, hunting together. The locations where I found them were roughly 2km apart, and the habitat surrounding both lakes is ideal for their year-round needs.

Sighting locations, shown by stars, 2km apart. Circles note 1.2km areas, but are misleading, since the home-ranges should be centered on the nest site, not the sighting locations. But they serve to give a rough estimate of the possible breeding-season home-ranges of two Red-shouldered Hawk pairs.

I suspect that I saw two pair of Red-shouldered Hawks on these two days, their home-ranges centered in the forests near the opposite sides of 40-acre Lake and Elm Lake, putting the nests substantially more than 2km apart. The pair at Elm Lake seemed more intensely colored (even taking into account the bright sunlight), while the pair at 40-acre Lake had slightly more muted colors. Both pair were seen out in the open, near the edges of mature mixed oak and deciduous hardwood forests; the forest edges would be perfect nest locations. I think it is somewhat less likely that I saw the same pair both days, since that would mean one pair was ranging quite a bit more than 2km from their nest site. But… it could be!

In either case, their home-range has expanded after hopefully successfully raising a family on the park’s plentiful squirrels, mice, toads and frogs, large insects, crawfish… and snakes. Noms!

And, now I can count at least one pair of Red-shouldered Hawks among my friendly acquaintances at Brazos Bend State Park, a park I’m happy to include in my own home-range.