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Southeastern Arizona Bird Observatory

Field Trip Photo Album

"Hawk Stalking" in the Sulphur Springs Valley

Photos by Tom Wood & Sheri Williamson


Hawk Stalkers travel in style in SABO's birding bus, "Moby"Located between Bisbee and Willcox, the Sulphur Springs Valley is one of the best winter birding areas in the country. Between November and March, up to twenty species of birds of prey and tens of thousands of Sandhill Cranes share the valley's desert scrub, grasslands and farm fields with a host of smaller birds, including Pyrrhuloxias, Curve-billed and Crissal thrashers, Lark Buntings, Scaled and Gambel's quail, and a variety of sparrows.

From December through February, SABO offers birding tours of the Sulphur Springs Valley. All-day "Hawk Stalks" focus on the identification, behavior and ecology of the raptors, cranes, sparrows and other wintering birds, while morning Sulphur Springs Valley Tours offer a relaxed introduction to majestic Sandhill Cranes and other species of the area's rare wetland habitats. For more information on winter activities for the 2002-2003 season, see SABO's Calendar of Events or e-mail us.

For field guides, CD-ROMs and more on hawks, owls, sparrows, and more, see SABO's Recommended Resources.


Western Red-tailed Hawk, rufous morph (photo by Sheri Williamson) Watching Red-tailed Hawks in the Sulphur Springs Valley is like hunting for Easter eggs—you know what size and shape you're looking for, but you never know what colors and patterns you'll find! This familiar member of the group of broad-winged soaring hawks known as buteos comes in a variety of regional variations and color varieties or "morphs." Western Red-tails such as this rufous morph can be either permanent or winter residents, while the pale-bellied Fuertes's Red-tail (a.k.a. "Desert Penguin") is the common breeding subspecies, and the usually blackish Harlan's Red-tail is a rare winter visitor from Alaska and western Canada. Red-tails are generalists whose favorite prey are the abundant rodents and rabbits that feed on both natural vegetation and farmers' crops. Road kills and other carrion provide additional nourishment, especially when live prey is scarce, and snakes and lizards spice up the menu during the warmer months.

Red-tailed Hawk © 2002 Sheri Williamson

Ferruginous Hawk, light morph © 2005 Tom Wood The Ferruginous Hawk, a big eagle-like buteo that hunts gophers, ground squirrels and prairie dogs, has suffered recent population declines that have conservationists worried about its future. Once a familiar sight in grasslands throughout western North America, this handsome raptor is now rarer than the Bald Eagle.

Unlike the Black-footed Ferret, Ferruginous Hawks managed to survive in good numbers despite the widespread destruction of prairie dog colonies and conversion of the prairies to agriculture. Their new problem seems to be human intrusion during the nesting season.

SABO is collecting data on Ferruginous Hawks wintering in the Sulphur Springs Valley to aid continent-wide conservation efforts.

Ferruginous Hawk © 2005 Sheri Williamson

The Ferruginous Hawk's proportionally small feet and large mouth fit its specialized diet. The broad yellow gape of this adult can engulf a gopher before marauders arrive to steal it but may also help the bird keep its cool by panting.

photo © 2005 Tom Wood

"Ferruginous" means "iron-colored," but only adults show the full range of coloration that inspired the name. The plumage of juveniles is steely gray and white without the rusty accents.
photo © 2005 Sheri Williamson
Ferruginous Hawk, dark morph adult
 
The light morph (above left and right) outnumbers the dark morph (left) by about 15 to 1. Both resemble Red-tailed Hawks, but the legs are feathered all the way to the toes.

photo © 1997 S. Williamson 
The oddest of North America's buteos and one of the most fascinating of all the world's raptors is the Harris's Hawk. These social birds live in family groups (right), also known as clans, that may include offspring from two or more nesting seasons and even unrelated individuals in addition to the breeding pair. The birds hunt cooperatively like a pack of wolves , using teamwork to overpower prey larger and more powerful than one bird would be able to tackle alone, and all share in the kill. The group's activities seem to be coordinated by the matriarch. These three individuals are part of a clan of five sharing a dead tree; note the relaxed pose of the bird at the far left. This species has been bred in captivity and often stands in for rarer birds of prey in movies and TV programs.

photo © 2002 Sheri Williamson

A family of Harris's Hawks (photo by Sheri Williamson)
Northern Harrier adult male © 2006 Sheri Williamson

Immature Northern Harrier (photo by Sheri Williamson)
The adult male Northern Harrier (upper left) is pewter gray above and silvery white below with striking black wingtips, while adult females and immatures are barred, mottled and streaked with shades of brown, cinnamon and cream. Adult males are greatly outnumbered by brown-plumaged females and immature males, making sightings of these "gray ghosts" a special treat. No matter what plumage they wear, all members of this species have bright white patches on the rump that are highly visible from above in flight—a convenient field mark since they're usually seen gliding low over fields and pastures. When they do come to rest, it's on the ground, as here, or on low, inconspicuous perches such as fence posts. In fact, harriers are perhaps the only hawk that avoids the utility poles that are so popular with other species (and so convenient for birders).

Harriers are unusual among hawks in using their ears more than their eyes to locate prey. The underlying structures of their owl-like facial disk (lower left) act like a parabolic microphone dish, collecting and concentrating sound. Unlike the fleet falcons they often resemble, the harriers' special talent is extremely slow flight, critical for tracking elusive mice and sparrows by their faint rustlings in the grass. The dark eyes on the bird at left identify it as an immature; adults, like the male above, have yellow eyes. In buteos such as the Red-tailed and Ferruginous hawks, dark eyes are a sign of maturity.

photos © 1997, 2006 Sheri Williamson

The Merlin is a mid-sized member of the falcon family. The Taiga or Boreal Merlin (right, female) is the most widespread of the three subspecies found in North America. Unlike most birds of prey, Merlins vary in color by both sex and age. The backs of adult males range from pale blue-gray in the Prairie Merlin to blackish slate in Black Merlin of the Pacific Northwest, while females and juvenile males are shades of sandy brown to chocolate. A winter resident of southeastern Arizona, Merlins make their living off small songbirds such as sparrows and Horned Larks plus the occasional dove (they were once known as the Pigeon Hawk here in North America). Between forays, they often hide in trees, as this female is doing while she dines on her most recent catch. The wizard of Arthurian legend took his name from the bird, not vice versa.

photo © 2002 Tom Wood

Female Taiga Merlin (photo by Tom Wood)
American Kestrel adult male © 2005 Sheri Williamson A male American Kestrel (right), the smallest of the four falcons species found in the Sulphur Springs Valley, surveys his domain from a utility pole. These colorful raptors are fairy common winter residents and uncommon breeders in the deserts and grasslands of southeastern Arizona. Once known as Sparrow Hawks in North America, kestrels occasionally capture small birds, but mice, grasshoppers, beetles, and lizards are the mainstays of their diet.

Adult male American Kestrels are smaller than their mates and more colorful, with slate blue areas on the wings, a broad black bar across the tip of the tail, and black "polka dots" on fawn to pale cinnamon underparts. Young males are similar to adult males but slightly duller, with narrowly barred tails like females.

This species was once common across North America but has declined as rural landscapes and traditional farming practices have given way to urban sprawl and industrial agriculture. 

photo © 2005 Sheri Williamson

The accipiters are highly maneuverable forest raptors that usually stay near thick cover and so are often hard to see—and to identify correctly. The Cooper's Hawk (below left) is a year-round resident and the accipiter most commonly seen in the Sulphur Springs Valley. Thicker legs, a rounded tail, and proportionally larger, more angular head distinguish them from the smaller Sharp-shinned Hawk (below right), and both adults and juveniles lack the prominent pale "eyebrow" of the larger Northern Goshawk, which rarely strays from its mountain strongholds. Cooper's Hawks are common year-round residents in forested habitats, while Sharp-shinned Hawks are primarily migrants and winter residents in southeastern Arizona.
Cooper's Hawk © 2005 Sheri Williamson

Sharp-shinned Hawk © 2004 Tom Wood

Accipiters have a reputation for fearlessness. The young Cooper's Hawk at far left didn't seem particularly perturbed by the humans who interrupted her bath at Whitewater Draw Wildlife Area. She'll wear these drab brown and ivory feathers for more than a year before replacing them with the blue-gray and rust plumage of an adult. It may take several years for her eyes to change from straw yellow to orange or red.

Though young birds are more commonly seen in open country, adult Sharp-shinned Hawks (near left) may also spend the winter hunting small birds in Sulphur Springs Valley. Note the even-length tail feathers, rounded head, and lack of contrast in color between the crown and nape.

Cooper's Hawk © 2005 Sheri Williamson
Sharp-shinned Hawk © 2004 Tom Wood

Sandhill Cranes in flight

From November to March, the skies of the Sulphur Springs Valley ring with the bugling calls of thousands of Sandhill Cranes. Up to 31,000 of these stately birds roost at playa lakes in the northern and southern ends of the valley. The first few cranes arrive in the Sulphur Springs Valley by early October, and the flocks grow through the fall as cold weather pushes migrants down from the north.

SABO's winter tours begin in late November, after crane hunting season is over and the cranes begin settling into their winter routine of feeding, loafing, and staying out of the way of natural predators such as Golden and Bald eagles.

photo © 2002 Tom Wood

Around sunrise the cranes begin their daily commute to nearby farms, where they'll fill their crops with waste grain and insects before returning to the roost for an afternoon of socializing, preening, resting, and digesting.

 As lengthening days signal the approach of spring, the cranes begin calling, dancing, and circling restlessly overhead. By mid-March, they depart for nesting grounds as far away as eastern Siberia (take a look at the map for Sandhill Crane #7548 at Operation Crane Watch).

Occasionally a bird stands out from the crowd; see SABO's Avian Oddities Photo Albums for unusual Sandhill Cranes.    

Bald Eagles and Sandhill Cranes © 2006 Sheri Williamson

A flock of cranes keeps hundreds of wary eyes on two Bald Eagles. Shortly after the cranes landed right in front of the all-dark young eagle, which showed little interest in all the potential prey right under its enormous bill, the adult flew in low and "strafed" the flock several times. Eagles prefer to attack cranes in flight, so when the flock refused to flush the eagle gave up and joined its young colleague on this popular perch.

Bald Eagles start out chocolate brown when they leave the nest and go through several awkward plumage stages over the next four years before gaining the characteristic white head and tail feathers and banana yellow bill. Young adults may show faint dark smudges on the face, especially behind the eyes.

 

photo © 2006 Sheri Williamson

The Vermilion Flycatcher, arguably the flashiest of all North American flycatchers, is a common sight in spring and summer around rare desert wetlands in the Southwest. Though most Vermilions depart southeastern Arizona in fall for warmer climates; one or more may overwinter at Whitewater Draw Wildlife Area, along with their less gaudy but more cold-hardy relatives, the Black and Say's phoebes.

Wintering birds may be immaculate adult males such as this dapper dude or less conspicuous females or immature males that are easily confused with other flycatchers. Look for patches of red on immature males and streaked breasts and bellies washed with yellow, peach, or pink in females.


photo © 2002 Sheri Williamson

Male Vermilion Flycatcher (photo by Sheri Williamson)
Greater Roadrunner (photo by Tom Wood)
The Greater Roadrunner is a common sight in the valley's brushland and open pastures. Almost any small animal is prey for these predators, including lizards, mice, small snakes, small birds, grasshoppers—even scorpions and centipedes. On chilly winter mornings, they're often seen facing away from the sun with their rump feathers ruffled to expose a patch of down-covered black skin that acts as a solar collector. They have been clocked at 15 miles per hour but probably can exceed that speed in short bursts.

photo © 1997 Tom Wood

The valley's scattered pockets of trees provide refuge for birds that crave more shelter than a landscape of grasses, shrubs, and row crops normally provides. For roosting and nesting, Great Horned Owls take advantage of native cottonwoods, willows, and mesquites as well as exotic trees planted for shade and windbreaks. The dense structure of an exotic pine conceals a lone owl roosting just yards from a busy highway (far right), but when cover is sparse the bird's natural camouflage can make it appear to be just another broken branch (below right). Great Horned Owl (photo by Sheri Williamson) photos © 2002 Sheri Williamson
Pairs of Great Horned Owls remain together year round, often roosting side by side. In late May 2002, SABO's Owls & More workshop group discovered that the female of a well-watched pair had been badly injured, suffering a concussion and severe damage to her left eye. A photo of this same bird taken on November 30, 2002 (near right) is testimony to the resilience of these fierce predators and the care she no doubt received from her mate during her recovery. Female Great Horned Owl (photo by Sheri Williamson)

Long-eared Owl © 2006 Sheri Williamson
photo © 2006 Sheri Williamson
Careful scanning of thickets of mesquites, hackberries, and willows may reveal splashes of "whitewash"—nitrogen-rich bird droppings—on trunks, branches, or leaf litter. Following the white marking upward sometimes leads to a roosting Long-eared Owl. This slim, medium-sized owl is a rare winter resident and ever rarer breeder in southeastern Arizona. Its habit of roosting low in dense vegetation protects it from ravens and other birds whose mobbing attacks are at best annoying and at worst potentially lethal.

Long-eared Owls are seldom as tolerant of human presence as the larger Great Horneds. Repeated disturbance may cause an owl to permanently abandon an otherwise secure roost, at best depriving others of the privilege of seeing it and at worst jeopardizing its survival. On the other hand, if left in peace, the same owl may return to the same roost day after day and year after year. Please avoid flushing roosting owls and encourage others - birders and nonbirders alike - to do the same.

Among southern Arizona's most sought-after winter residents is the Mountain Plover, one of many grassland species whose populations have plummeted as humans have altered or destroyed their habitats. In the Sulphur Springs Valley, this understated cousin of the Killdeer is often seen in hayfields and close-cropped pastures in the company of their gaudy, noisy relatives, scurrying to and fro in search of insects. These dry-land shorebirds adapted to life in the short-grass prairies of the western Great Plains now depend in large part on prairie dog towns for breeding habitat. They're less demanding in winter and will use a variety of agricultural fields. In all season they need wide-open spaces with good visibility in all directions; nests made in farm fields are usually abandoned when the crop grows too high. Efforts to ensure a future for this species include cooperation with farmers and ranchers in habitat protection and restoration and seasonal restrictions on human activities in critical breeding areas. For more on this declining prairie plover, see the Audubon WatchList species account.
photo © 2006 Sheri Williamson
For more information on SABO's field trips, tours and workshops, please write, call or e-mail:
Southeastern Arizona Bird Observatory
P.O. Box 5521
Bisbee, AZ 85603-5521
(520) 432-1388
Contact SABO


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