Greater Roadrunner
The most famous bird in the Sonoran Desert, without a doubt, the Roadrunner is also the most fictionalized in popular imagination. Cowboys used to tell tall tales about how Roadrunners would seek out rattlesnakes to pick fights, or would find sleeping rattlers and build fences of cactus joints around them. A later generation of Americans grew up thinking that Roadrunners were purple and cried “beep beep” as they sped about.
 | Even without such stretches or inventions, the real Roadrunner is impressive. Running in the open (and not just on roads), it reaches fifteen miles per hour. It can fly, but usually doesn’t. Often it seems curiously unafraid of humans. Trotting up close to peer at us, raising and lowering its mop of a shaggy crest, flipping its long tail about expressively, it looks undeniably zany. It comes as no surprise to learn that the Roadrunner is a member of the cuckoo family. |
Clownlike it may appear to human eyes, but the Roadrunner is a very effective predator. Its speed on foot is not just for show: it captures not only snakes and large insects, but also fast-running lizards, rodents, and various small birds. Gambel’s Quail may pay scant attention to the Roadrunner at most seasons, but they react to it violently when they have small young, and with good reason: given an opportunity, the Roadrunner will streak in to grab a bite-sized baby quail.
—Kenn KaufmanGreater Roadrunner (Geococcyx californianus)
Order: Cuculiformes
Family: Cuculidae (Cuckoos)
Spanish Names: correcaminos, churea, paisano
Distinguishing features
Our largest cuckoo, this bird is characterized by a long tail, streaked appearance, frequently erected shaggy crest, and a blue and orange bare patch of skin behind the eyes. It is capable of running very rapidly across the ground (15 mph) and rarely flies. Like all cuckoos, the Roadrunner is a zygodactyl bird (it has 2 toes pointing forward and 2 toes backward).
Habitat
The Roadrunner prefers open country, desert, open pinon/juniper habitat.
Feeding
• Diet: Feeds upon any animal small enough for it to kill and ingest, including small birds and snakes; young are fed insects, lizards, and mice; also eats some fruits and seeds.
• Behavior: Hunts by walking briskly and running toward prey once it is located; also able to jump straight up in the air when small birds or flying insects are overhead. The adult uses its long tail as a rudder for maneuvering while running.
Life History
The pair bond in this species may be permanent; pairs are territorial all year. Courtship displays include, but are not limited to, presenting the mate with a twig or piece of grass and chasing one another.
The nest, which is constructed of twigs, is frequently found in cholla, mesquite, or palo verde. White eggs (3 to 6) are laid at intervals; if food is scarce the older, larger hatchlings will quickly seize all the food from the parents thus causing the younger, smaller ones to starve. Rarely do all nestlings reach maturity. If not enough food is available, these younger birds will be fed to the other, stronger hatchlings.
Roadrunner skin is heavily pigmented. On cool mornings, the bird positions itself with its back towards the sun and erects its feathers, thus allowing the sun to strike directly on the black skin which quickly absorbs heat energy. This makes it possible for the bird to achieve body heating without unnecessary expenditure of metabolic energy.
Owls
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The Sonoran Desert at night is a very lively place. Especially in summer, there are probably more creatures abroad at midnight than at noon. Of course, most birds shun this night shift, but several species of owl are notable exceptions.
Owls are superbly equipped to hunt at night. They cannot see in total darkness— no animal can do that—but their eyes are adapted for vision under very low light conditions. Even more impressive is their sense of hearing. Studies have shown that Barn Owls can locate their prey by sound alone, in total darkness, with pinpoint accuracy. Many of the creatures that they hunt also have excellent hearing, but the owls can approach them in silence: the sound of their wingbeats is muffled by the softened edges of the larger wing feathers.
Great Horned Owls are found throughout the Americas and Barn Owls practically throughout the world, so it is no surprise that they can adapt to desert life. Great Horned Owls eat almost anything smaller than themselves from rabbits and skunks to snakes and insects. Barn Owls specialize on rodents and the smaller desert owls also tend to take small prey. The Ferruginous Pygmy-Owl, a tropical species that reaches its northern limit here, may hunt most at dawn and dusk, often catching songbirds. The world’s smallest owl, the Elf Owl, nests in holes in saguaro cacti and ventures out at night to eat beetles and moths. Nocturnal insects are scarce in cold weather, so most Elf Owls retreat south into Mexico for the winter; other desert owls are present year-round.
—Kenn KaufmanOwls
Sonoran Desert species:
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Barn Owl (Tyto alba)
Western Screech-Owl (Otus kennicottii)
Great Horned Owl (Bubo virginianus)
Ferruginous Pygmy-Owl
(Glaucidium brasilianum)
Elf Owl (Micrathene whitneyi)
Burrowing Owl (Athene cunicularia)
Order: Strigiformes
Family: Strigidae (all but Barn Owl)
Family: Tytonidae (Barn Owl)
Spanish names: lechuza mono, lechuza común (Barn Owl), tecolotito chillon
(Western Screech-Owl), tecolote cornudo, buho (Great Horned Owl), tecolote enano (Elf Owl), lechuza llanera, lechuza de ojo
(Burrowing Owl)
Distinguishing Features
Barn Owl: This is a long-legged, knock-kneed, pale, monkey-faced owl. It has no ear tufts, and the pale face resembles a heart-shaped disc. The back is golden-brown, the belly is white. The voice is a loud, rasping screech. Western Screech-Owl: A common bird in our area, it is small, measuring only about 8 inches (20 cm). It is gray, streaked with black and white, has conspicuous “ear” tufts and is zygodactylous (2 toes point forward, 2 backward). Its call, a trill of several notes that become more rapid (like a bouncing ball), distinguishes it from the similar Whiskered Screech-Owl, which lives in oak woodlands. Great Horned Owl: Measuring almost 2 feet (61 cm) tall, this is our largest owl. It has a white throat, barred underside, and prominent ear tufts. Ferruginous Pygmy-Owl: This small (6¼ to 7 inch; 17 cm), uncommon, “earless” owl is reddish-brown with a faintly cross-barred tail. The crown has many white streaks and the underside is white with red-brown streaks.
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Elf Owl: About the size of a sparrow (5 inches tall; 13 cm), this is one of the smallest owls in the world. It has no ear tufts, and is grayish-brown with a white brow. The call consists of a variety of soft yelping notes, often running together into a high-pitched chatter. Burrowing Owl: About the size of a screech-owl, it is brown, spotted with tan, and lacks ear tufts; the long legs are almost featherless.
Habitat
Barn Owl: This owl occurs throughout our area and through much of the U.S., Europe, Asia, and Africa. It is widespread but local. It is often found in conjunction with human habitation, roosting and nesting in barns, under bridges, in mine shafts, and in palm trees. It often nests in the undercuts of arroyos.
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Western Screech-Owl: The screech-owl occurs from southwestern Canada into Mexico. It is a resident of wooded areas from low desert into the mountains.
Great Horned Owl: This owl occurs throughout the New World, except the extreme north. It is found in every habitat within our region.
Ferruginous Pygmy-Owl: This species ranges from southern Arizona and southernTexas, south through Central and South America. The Ferruginous Pygmy-Owl is found in saguaro deserts and wooded river bottoms. In the tropics it inhabits a wide variety of wooded or semi-open habitats.
Elf Owl: The Elf Owl occurs from western Mexico through the southwestern United States. In our region, it may be found mostly in riparian habitats or in association with the saguaro.
Burrowing Owl: This species occurs from southwestern Canada to Tierra del Fuego, at the tip of South America. It prefers open country, prairie and desert. It is frequently seen in desert and grassland regions, standing on mounds or fence posts during the day.
Feeding
• Diet: The Barn Owl feeds on large numbers of rats and mice. Western Screech-Owl feeds on invertebrates and vertebrates. The Great Horned Owl has an extremely varied diet that includes birds, skunks, snakes, lizards, insects, and even frogs and fish. Lagomorphs (rabbits and hares) and rodents make up the bulk of the diet. The Ferruginous Pygmy-Owl prefers lizards and large insects, but will also take scorpions and small birds and mammals. The Elf Owl feeds primarily on invertebrates such as scorpions, centipedes, beetles and moths. The Burrowing Owl feeds on insects, rodents and small reptiles.
• Behavior: Barn Owl: An expert nocturnal predator, it finds its prey at night with exceptionally acute hearing and vision. The owl, like most birds of prey, ingests bone and fur when it eats its prey. However, the digestive processes of the owl are not capable of digesting bone and fur. This residual material is formed into a pellet in the stomach and regurgitated. Food habit studies of owls are easily done by examining the contents of the pellets found in or near their roosts. Western Screech-Owl: The streaked pattern of the owl blends well with desert shrubs while hunting. Highly nocturnal. Great Horned Owl: A nocturnal predator with extremely acute sound perception and night vision. The soft feathers are an adaptation to its hunting style of obtaining food. These feathers do not make any sound in flight; therefore, the bird can hear the prey and locate its position, but the prey cannot hear the owl. This owl is an extremely important predator of jackrabbits and cottontails. Ferruginous Pygmy-Owl: This pugnacious owl is most active at night, but it is also active during the day, especially at dawn and late afternoon.
Life History
Barn Owl nesting activity peaks in the spring, with 5 to 6 white eggs laid in a depression in a tree cavity, cave, mine shaft, or building. The female incubates the eggs about 33 days. The young remain in the nest for 7 to 8 weeks. The barn owl characteristically begins incubating the first egg, and while incubating it, lays additional eggs. Since the eggs are laid 1 to 2 days apart, the young hatch 1 to 2 days apart. Therefore, chicks of various ages (development stages) can be found in one nest. Often the older siblings starve out the younger. Once one dies, it is fed to the older nestlings. The young are very noisy, crying raucously when the adults feed them.
The Western Screech-Owl nests in tree cavities; in our area it commonly nests in saguaro holes. The eggs are white with 4 to 5 in a clutch. They are incubated for about 26 days. The male feeds the female during incubation.
The Great Horned Owl begins nesting during January or February, usually in an abandoned hawk nest or on a ledge. The white eggs are usually laid 2 or 3 to a clutch. The owls actively defend the nest territory.
The Ferruginous Pygmy-Owl female lays 3 or 4 white eggs in hollows of saguaros or other trees. The nest, which contains no nesting materials, may be used for many years. The incubation period is about 28 days; the male feeds the sitting female and both parents feed nestlings. The young are able to fly 27 to 30 days after hatching.
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The Elf Owl uses old woodpecker nest cavities for its nests. The white eggs are usually laid 3 to 4 to a clutch. Starlings, which are an introduced bird from Europe, pose a threat to Elf Owls. They take over nest cavities already in use by the Elf Owls, or by other birds.
The Burrowing Owl nests in the used burrows of other animals, most commonly ground squirrels and prairie dogs. The white eggs number from 5 to 10, and are laid in underground nests. The babies spend most of their early life underground, but emerge before they are fully fledged to exercise their flight muscles. When disturbed in a burrow, the owl mimics a rattlesnake’s rattle. The adults are probably preyed upon by other predators; the chicks are taken by snakes.
Nightjars
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Nightjars are birds of mystery. Camouflaged in mottled brown and gray, they generally hide and sleep during the day, resting on the ground or on horizontal branches with their big eyes closed. At night they emerge to fly about, as silent in the air as the moths that they often capture in their wide, gaping mouths. Many nightjars are best known by, and named for, their nocturnal songs; the Whip-poor-will, which reaches the mountain forests of the southwest, is a good example.
Around rocky outcrops in the desert, the lonesome cry of the Poorwill is a familiar sound on summer nights, especially when the moon is bright. Naturalists who are out at night may find Poorwills sitting on roads, and may even be able to watch them hunt when the birds flutter up from the ground to catch passing insects. Poorwills mostly disappear from our region in winter, but they are not necessarily gone: these are the only North American birds known to hibernate, and they may sleep for days or even weeks at a time.
The Nighthawks (not related to hawks at all) are the most aerial of the nightjars, longer-winged and more buoyant in flight than their relatives. They are often seen flying about at dawn or dusk, or even in full daylight. The Lesser Nighthawk of the Southwest looks very much like the Common Nighthawk, widespread in North America, but the species differ in behavior. Common Nighthawks are flamboyant birds, flying high and calling loudly; but Lesser Nighthawks tend to fly low, and they usually maintain an eerie silence, floating like ghosts over the desert at dusk.
—Kenn KaufmanNightjars
Representative Sonoran Desert species:
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Lesser Nighthawk (Chordeiles acutipennis)
Common Poorwill (Phalaenoptilus nuttallii)
Order: Caprimulgiformes
Family: Caprimulgidae
Spanish names: tapacamino, garapena
Distinguishing Features
Both birds have large eyes, tiny bills, huge gapes, and short legs. Nighthawks are larger (8-9 inches; 20-23 cm) and are identified in flight by a white wing bar and pointed wings. Poorwills (7-8¼ inches; 17.5-21.5 cm) have rounded wings and no white bar.
Habitat
The Nighthawk and Poorwill are found in all Sonoran Desert habitats. The Poorwill is more common on sparsely vegetated bajadas.
Feeding
Both Nighthawks and Poorwills are insect-eaters, but their hunting techniques differ: the Nighthawk flies low, silently and gracefully, searching the sky for flying insects, and maneuvering quickly, almost like a bat. A hunting Poorwill sits on open ground, looking up into the sky for the backlit silhouettes of large moths or beetles. When it spots something, it flutters up, usually no higher than ten feet, and catches the insect in its mouth. Both birds are crepuscular, needing some light to hunt by. City lights may extend the activity of the more urban Nighthawk and also attract its prey. Lesser Nighthawks may also be seen until midmorning. Poorwills like hunting by moonlight (they’re lunarphilic) and on these nights they take over the niche of the lunar-phobic, insect-eating bat.
Life History
During the day, Lesser Nighthawks and Poorwills rest on the ground or horizontally on a branch, well camouflaged by their cryptic coloration. During winter, Lesser Nighthawks migrate, and Poorwills may too. But they may also hibernate, greatly l owering body temperature, respiration, and heart rates for days, even months, at a time. This behavior is very unusual in birds—hummingbirds enter torpor, but only for one night. The first documented hibernating Poorwill was found in the Sonoran Desert, in a hollow in a rocky canyon. Its discoverer tried to find signs of life in this apparently dead bird by catching the condensation of its breath on a mirror, but failed. Ten days later, the bird still hadn’t moved, but when the man touched it, the bird winked at him.
White-throated Swift
No other birds in the world are so purely creatures of the air as are the swifts. Small birds with short tails and saber-shaped wings, they speed through the sky in search of flying insects. Their small feet are not designed for perching in normal bird fashion; they can only cling to vertical surfaces, so they land only when necessary. Their nests are made primarily of their own saliva, which hardens to a substance resembling shellac (the nests of some Asian species, which separate into gelatinous shreds when soaked and cooked, are the source of bird’s nest soup). Except during the season when they are raising young, or during very bad weather, swifts may spend all their waking hours in flight. Some European swifts are even thought to sleep in the air.
The only member of the family normally seen over the southwestern U.S. lowlands is the white-throated swift. Little colonies nest in crevices in the rocks of cliffs and canyons, but flocks may be seen anywhere over the desert. Sometimes they are almost too high to see, and only their high-pitched chattering gives them away; sometimes they course low over the ground. They are perhaps best seen along the rims of canyons, where they may go hurtling past at breathtaking speeds. Some people have suggested that white-throated swifts might exceed 200 miles per hour in level flight; although it would be hard to measure this, anyone who has seen them zoom past at close range will not find it hard to believe.
—Kenn KaufmanWhite-throated Swift (Aeronautes saxatalis)
Order: Apodiformes
Family: Apodidae
Spanish Names: vencejo, golondrina
Distinguishing Features
The White-throated Swift has long, narrow, stiff wings; their black and white pattern distinguishes this species from other North American swifts.
Habitat
The White-throated Swift roosts and nests in the crevices of cliff faces. It forages over all desert habitats in open sky.
Life History
Swifts spend most of their time in the air, foraging for flying insects. Eating, drinking, bathing, even courtship and copulation take place in the air; during mating the pair tumbles downward, sometimes for over 500 feet (250 m). Nests are built in crevices of cliffs; they are made of grass and feathers glued together with saliva. The same nest sites may be used year after year by a colony of these social birds.
Although the family name means “without feet,” swifts do have feet—unusual ones, in which the 4 toes point forward. This, and the exceptionally long claws, are thought to be adaptations to clinging to vertical surfaces, such as cliff faces or nests. The legs of swifts are small and weak, as suits an animal that so rarely touches down. White-throated Swifts may be the fastest flying North American birds. Both nestling and adult White-throated Swifts can become torpid during cool weather or food shortages.
Born to Fly
Aerodynamically, flight is the triumph of lift and propulsion over gravity and drag. In flapping flight the outer wing feathers (primaries) produce the propulsion, and the inner wing feathers (secondaries) produce the lift. Lift is generated by air moving over an air foil, or wing. In addition to flapping flight, birds also glide and soar. In gliding flight, birds gradually lose altitude on steady out-stretched wings. In soaring flight, birds gain altitude on steady out- stretched wings by riding updrafts of air.
The demands and advantages of flight have produced some dramatic adaptations in birds. One of these adaptations centers around weight reduction.
Weight Reducing Adaptations in Birds:
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• Some large bones are thin and hollow
• Some bones are fused or reduced in size, e.g. the bones of the front limb and tail
• Feathers provide light strength
• Few skin glands
• No teeth or heavy jaws
• Air sacs
• Ovipary not vivipary (they lay one egg at a time)
• Atrophy of reproductive organs between breeding seasons
• Usually only one ovary
• Generally select high calorie, compact foods (such as seeds and insects)
• Rapid and efficient digestion
• No bladder; they excrete a dry, light-weight uric acid
Hummingbirds
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Describing hummingbirds without resorting to superlatives would be difficult, and hardly fair. This family includes the world’s smallest birds, with the most brilliant iridescent colors, the fastest wingbeats, and the most amazing ability to fly up, down, sideways, and backwards. They spend their days hovering at flowers to sip nectar, feeding almost constantly to supply the sugar necessary to maintain their racing metabolism. Many people would call these the world’s most fascinating birds.
The brightest colors and most ornate patterns among hummingbirds are worn by males, and the purpose is evidently to impress females. After mating, the male takes no more part in family life. The female alone builds the nest, incubates the tiny eggs, and feeds the young. Considering the amount of energy that an individual hummingbird needs just to feed itself, it seems remarkable that the female is able to raise the young successfully all alone.
There are well over three hundred species of hummingbirds, all native to the Americas. The vast majority, not surprisingly, are found in the tropics, where flowers abound year-round. Only a handful of species reach the United States; southern Arizona hosts more than a dozen of those. Costa’s Hummingbird is the only true desert hummer here, but several others live along the desert’s edges. Black-chinned and Broad-billed Hummingbirds nest in streamside woods in summer, while Anna’s Hummingbird, a recent invader from California, nests in the same areas (and in residential neighborhoods) in winter. Our region hosts the greatest variety of hummers in late summer, when several species are on their way south. Rufous Hummingbirds, southbound from nesting grounds in the northwest U.S., may appear in the Sonoran Desert by July, along with lesser numbers of other species, to joust for space around the blooms that follow the summer rains.
—Kenn KaufmanHummingbirds
Representative Sonoran Desert species:
Broad-billed Hummingbird (Cynanthus latirostris)
Black-chinned Hummingbird (Archilochus alexandri)
Anna’s Hummingbird (Calypte anna)
Costa’s Hummingbird (Calypte costae)
Rufous Hummingbird (Selasphorus rufus)
Order: Apodiformes
Family: Trochilidae
Spanish names: chuparrosa (hummingbird), chuparrosa matraquita
(Broad-billed Hummingbird), chupamirto garganti-negro (Black- chinned Hummingbird), chupamirto cuello escarlata (Anna’s Hummingbird), chupamirto garganta violeta (Costa’s Hummingbird), chupaflor dorado (Rufous Hummingbird)
Description
The smallest birds in the world belong to this family. In our region, they range in length from 2¼ inches to 5 inches (7 to 13 cm), and from 2 g to 10 g in weight. All in our region have long, pointed beaks for probing flowers for nectar, saber-like wings for hovering in front of flowers, a generally iridescent bronze or green dorsal surface, and primarily in males, bright, colorful throat and head patches. The iridescent throat patch is called the gorget (pronounced gore-jet).
Distinguishing Features
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Broad-billed Hummingbird: 4 inches (10 cm) in length; 3 g to 4¼ g in weight. In poor light the males appear dark with red bills and forked tails. In good light, the male’s head and breast are metallic blue or blue-green. The females are a duller grey-green, but retain the dark forked tail and have red only at the base of the lower mandible.
Black-chinned Hummingbird: 3¼ inches (9 cm) in length; 3 to 4 g in weight. This hummingbird is iridescent green above and gray below. The male has a velvet black throat, the bottom border of which iridesces violet in good light. The dark throat patch contrasts strongly with a white upper breast, giving a collared effect. The females lack dark throat patches.
Anna’s Hummingbird: 4 inches (10 cm) in length; 3¼ g to 5 g in weight. These “flame-throated” hummingbirds are iridescent green above and grey below. In addition, the male’s throat and forehead iridesce crimson rose in good light; in poor light, these areas appear to be velvety black. The females generally lack these iridescent rosy patches, but may have a few rose feathers on the throat.
Costa’s hummingbird: 3¼ inches (9 cm) in length; 2¼ g to 3¼ g in weight. This “flame-throated” hummingbird is iridescent green above and grayish white below. The males in good light have an iridescent amethyst purple forehead and throat. The iridescent throat patch extends into an elongated “mustache.” In poor light, these patches appear velvety black. The female completely lacks these patches.
Rufous Hummingbird: 3¼ (9 cm) inches in length; 3 g to 4 g in weight. The male is cinnamon-rufous on the upper parts, tail, and lower breast and belly. In good light, the throat iridesces a metallic orange to scarlet. The female is iridescent bronze-green above and dull white below. She also has a cinnamon wash to the flanks and much rufous on all the tail feathers.
Habitat
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Hummingbirds occupy most temperate and tropical habitats in the western hemisphere. In our region, they can be found in desert, grassland, woodland, and forest. They tend to prefer edges of dense habitats, and the scrubbier areas of open habitats.
Broad-billed Hummingbird: In Arizona and Sonora, the broad-bill is found in the lower mountain canyons and in the mesquite bosques of the larger washes and rivers. Habitats also include the thorn forest and thornscrub of southern Sonora.
Black-chinned Hummingbird: This is the “summer hummer” in southern Arizona. The bird winters in Mexico. In Arizona, the Black-chin inhabits deciduous woodland associations in low mountain canyons, desert riparian habitats, and cities. It is generally absent from desertscrub.
Anna’s Hummingbird: The Anna’s Hummingbird is generally considered a sedentary resident bird of the Pacific Slope, west of the Sierra Nevada Mountains, with some birds visiting southern Arizona and northern Sonora in the fall and winter. Since the 1960s the number of fall and winter visitors to Arizona has increased greatly, as has the number of breeding birds in our area. The first nesting in Arizona occurred in 1962. In Arizona, Anna’s Hummingbirds are found in residential areas most commonly in association with feeders and exotic plantings. They can also be found in desertscrub and riparian woodland.
Costa’s Hummingbird: This hummingbird inhabits desertscrub communities dominated by cactus, ocotillo, chuparosa, and wolfberry. It is probably our most arid-adapted hummingbird.
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Rufous hummingbird: This hummingbird breeds in the northwestern United States and western Canada and winters in Mexico. It tends to migrate north through western Sonora, western Arizona, to the Pacific coast; it tends to migrate south through the Rocky Mountains, including eastern Arizona. This annual migration path forms a broad oval over most of western North America. The males generally migrate before females and immatures. During migration in Arizona and Sonora, the Rufous uses a wide variety of habitats from desertscrub to mountain meadows, wherever there are flowers or feeders.
Feeding
Hummingbirds are the dominant nectarivorous birds in the western hemisphere. Old World ecological equivalents include the honey-eaters of Australia and the sunbirds of Africa. Although many of these other birds may have specialized bill shapes and foot types for getting nectar, and some have bright or iridescent plumage, none achieve the specialization to nectarivory that the hummingbird has. Hummingbirds also eat many small, soft-bodied arthropods.
Life History
North American hummingbirds are highly territorial, both sexes protecting feeding territories, males protecting courtship territories, and females protecting nesting territories. These territories are protected by displays, songs, chases, or the mere presence of the hummer on an exposed perch.
Hummingbirds are promiscuous breeders. The male merely courts and mates with receptive females. The female may mate with more than one male, but she alone builds the nest, lays and incubates the eggs, and broods and tends the young.
The nest is not much larger than a jigger glass. It is typically composed of fibrous plant down or seeds and mosses, bound together and to a branch with spider webbing. The nest may be lined with hair or feathers and decorated with leaves, bark strips, or lichens, depending on the species.
Only 2 bean-sized eggs are laid and incubated for about 2 weeks, depending on the species.
Young are altricial and are fed a mixture of nectar and small, soft- bodied arthropods like spiders and gnats. They fledge in about 3 weeks depending on the species and to some extent on the weather.
Like many animals, most hummingbirds die during their first year. After that, their life expectancy may increase to 3 or 4 years. Few live past this, although there is a record of a Broad-tailed Hummingbird living 11 years.
Broad-billed Hummingbird: In Arizona, Broad-bills nest from April through July. In Sonora, they may start earlier. The nest is saddled on a horizontal limb and is typically decorated with long strips of bark or leaves. The males have a short, buzzing, scratchy advertising song.
Black-chinned Hummingbird: Black-chined Hummingbirds breed in Arizona from April through July. The male’s dive display consists of a swooping pendulum-like dive of about 100 feet (30 m). There is a loud whirring sound at the bottom of the pendulum that is presumably produced by the wings or tail.
Anna’s Hummingbird: The Anna’s Hummingbird is among the earliest of our nesting birds. Nests with young have been recorded in December in Tucson. The breeding season may extend through May. The male Anna’s is the most vociferous hummingbird in our region. Its advertising song of squeaks and buzzes is louder and more “musical” than most. Both the male and female give a “war cry” consisting of a rapid series of buzzes when they chase intruders from their area. The male also exhibits a dive display in the shape of a 100 foot (30 m) “J.” At the bottom of the dive, he gives a loud squeak.
Costa’s hummingbird: The breeding season in Arizona and Sonora is late winter and spring. Some breeding may occur later in Baja California and in southern California. The males have a “song” consisting of one drawn-out whistle, reminiscent of a ricocheting bullet. This may be given from a prominent perch or at the bottom of its U-shaped dive display.
Rufous Hummingbird: In our region, the Rufous is known only as a migrant and a very pugnacious hummer at feeders.
Comments
A related species, the Allen’s Hummingbird, Selasphorus sasin, also occurs in our region as an uncommon migrant. The males have a greener back than the Rufous and the females are almost indistinguishable.
Sweating the Details
Hummingbirds “decorate” their nests to camouflage them, weaving leaves and sticks and plant fibers into the outer part of the nests. In the Desert Museum’s hummingbird exhibit, however, the nest-building females frequently take thread, yarn, and even hair from visitors to weave into their nests. Some of the females are quite daring and will even land on visitors in order to pull out a particularly choice piece of yarn. I have worried that a bird might get hurt flying so close to people, but the visitors have always been very calm and gentle. They have been extemely generous also. At one point I even received a sweater in the mail, accompanied by a note explaining that one of the Costa’s hummingbirds in the exhibit had taken an extreme interest in the sweater and seemed sorry to see it go when the wearer left the exhibit. “Take the sweater back to the hummingbird exhibit,” the note read. “She can use it more than I can!”
—Karen KrebbsHummingbirds & Spider Webs
When we opened the Arizona-Sonora Desert Museum’s hummingbird aviary in 1988, we had no idea whether or not any of the eight species of the birds on exhibit would breed and rear young. Since opening day, however, we’ve seen Costa’s, Broad-billed, Black-chinned, Anna’s, and Calliope hummingbirds nest, lay eggs, and rear young. There have been a total of 114 nests built, 186 eggs laid, 116 birds hatched, and 102 birds fledged. No other zoological institution can boast of such success.
But this success has not come without a good deal of effort on the part of the exhibit keepers and the hummingbirds—especially when it comes to nest-building. For example, in 1992 we renovated the exhibit, clearing out all the plants and expanding and replanting the new space. Within a month of the renovation, several hummingbirds began to build nests. The nests were loose and quite fragile, and even experienced nesters were having difficulty. Most of the nests fell apart and we lost several eggs that fell out and broke. We scratched our heads for days trying to figure out the problem before we finally concluded that a primary component of hummingbird nests was missing—spider webs! Hummingbirds use spider webbing as a way to bind and tie their nests together. The spiders had yet to reestablish themselves in the spanking new exhibit. I immediately went out and collected webs from around the grounds, rolling them up on twigs, which I left in the aviary. The Desert Museum’s entomologist and I also collected 25 labyrinth spiders and introduced them. Within days the spiders were weaving their webs in the aviary and the birds’ nests immediately improved.
—Karen KrebbsPowering Down
Being a hummingbird is like driving a car with a one-gallon gas tank: there is an almost constant need to refuel. Hummingbirds are often perilously close to the limits of their energy reserves. On cold nights, when the costs of keeping warm are especially high, it may be too risky for a hummingbird even to keep its engine idling.
At such times, a hummingbird bristles its feathers to let its body heat escape, and its temperature quickly approaches that of its surroundings. Its heart rate drops dramatically and it may stop breathing for minutes at a time. It appears lifeless, clinging motionlessly to its branch with its head drawn close to its body and its bill pointing sharply upward. At daybreak it revs its metabolic engines and warms itself again.
This sort of temporary hibernation is called torpor. Hummingbirds become torpid not only to deal with fuel crises, but also to save energy for migration. And since birds lose moisture with every breath, becoming torpid also helps desert hummingbirds conserve water.
-David W. Lazaroff, The
Secret Lives of Hummingbirds (ASDM Press, 1995) 
Hummer Facts
- Hummingbirds’ hearts are larger in proportion to body size than those of any other warm-blooded animal.
- Hummers have the most rapid heart rate for a bird: up to 500 beats per minute at rest and 1260 beats per minute during activity.
- Their flight muscles account for 25 to 30 percent of body weight, compared to 15 to 25 percent in other strongly-flying birds.
- Hummers have the most rapid wing beats of birds: up to 80 beats per second.
- Their unique flight mechanisms allow them to hover for long periods of time, move in any direction (even backwards), and dive at over 60 miles per hour during displays.
- They have high body temperatures: 105° to 109°F (40.5° to 42.5°C).
- They have the ability to become torpid at night. (See the sidebar “Powering Down” on the next page.)
- Hummingbirds may consume 70 percent of their body weight, in solid food per day (8 to 12 calories) and 4 to 8 times their body weight, in water.
- There are over 300 species of hummingbirds. They live exclusively in the Western Hemisphere, from Alaska to the tip of South America.
Woodpeckers
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We expect woodpeckers to be in the woods, so it may seem surprising that some are conspicuous in the desert. But for Gila Woodpeckers and Gilded Flickers, saguaros serve in place of trees: these woodpeckers go hitching their way up the sides of the giant cactus, and give voice to strident calls when they reach the top. The holes that they excavate for nesting sites—which may riddle the arms of some ancient saguaros—remain to serve as natural birdhouses for a variety of other birds.
Most woodpecker species feed mainly on insects, seeking them out among the irregularities of tree bark. In the desert, these birds must be more resourceful. Gila Woodpeckers eat cactus fruits, mistletoe berries, and many other items in addition to insects. Highly adaptable, they make themselves at home in southwestern U.S. cities, where they will visit hummingbird feeders and steal dog food from back porches. (They also make themselves unpopular at dawn by hammering out brash wake-up calls on metal pipes and other echoing objects.) Gilded Flickers spend much time foraging on the ground; they are among the few birds that regularly eat ants. Ladder-backed Woodpeckers, among the smaller members of this family, make their living in a more traditional woodpecker style on the trunks of mesquites along desert washes.
—Kenn KaufmanSonoran Desert species:
Gila Woodpecker (Melanerpes uropygialis)
Ladder-backed Woodpecker (Picoides scalaris)
Gilded Flicker (Colaptes chrysoides)
Order: Piciformes
Family: Picidae
Spanish names: carpintero de Gila (Gila), párajo carpintero, picapalo
Distinguishing Features
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Gilded Flickers: Brown birds, with black barring on their backs and white rumps, visible as they fly; underside of wings and tail is golden. Gila Woodpecker: Brown face, black and white barred back, white wing patches that are visible when in flight. Ladder-backed Woodpecker: Black and white barred backs; face has black and white stripes.
Habitat
These woodpeckers are permanent residents that are found in all desert habitats.
Feeding
• Diet: As a group, woodpeckers are adapted to locating and capturing invertebrates living in the bark of trees. While these 3 species often look for insects on the side of a tree, they are also opportunistic. The flicker is often found on the ground eating ants, and all 3 eat cactus fruit.
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• Behavior: These woodpeckers have strong head and neck muscles, and the skull is adapted to absorb the shock as the birds drive their chisel-shaped bills into the tree. The tongue is long and can be extended; its tip is bristled and sticky. Short legs, strong toes, sharp claws and stiff tail feathers keep these birds secure on the vertical surface of trees.
Life History
Woodpeckers nest in cavities that they excavate. In the Sonoran Desert, Flickers and Gila Woodpeckers build nests in saguaros; the interior of the cactus provides a secure environment where the temperature is moderated year around. After the woodpeckers are finished with them, their nests are used by other birds—Elf Owls, Kestrels, Ash-throated Flycatchers, Purple Martins. According to some research, flickers and Gila Woodpeckers nest at different heights in the saguaro: flickers within 3 meters (10 feet) of the top, woodpeckers lower. The difference seems due to the fact that woodpecker nests are excavated in the outer cortex, whereas flickers need larger cavities, so their excavations go further toward the thicker center of the cactus—through the ribs and into the inner pith. Flicker bills are not adapted to heavy-duty boring: toward the top of the cactus the ribs are thinner and more easily severed. Flicker cavities may harm the saguaro, even kill it, because water is no longer transported through the vascular tissue of the severed ribs and because the excavation increases surface area/volume ratio leading to greater water and heat loss.
Tyrant Flycatchers
 | Birdwatchers are sometimes driven to despair by the challenge of telling the various flycatchers apart. Many of the species look virtually the same. Birds have to be able to recognize their own kind, of course, at least during the breeding season, but the flycatchers evidently do so mostly by voice. In the Sonoran Desert, for example, the Brown-crested and Ash-throated Flycatchers are almost identical except for size, but their songs and calls are different. Perhaps capitalizing on their need for vocal distinctions, many flycatchers have “dawn songs,”seldom heard later in the day. |
Flycatchers in North America feed mainly on insects, and forage by watching from an exposed perch and then sallying forth to pick flying insects out of the air. In this they are aided by their wide, flat bills, and by the bristles on either side of the bill. The little beardless-tyrannulet is so called because it lacks these bristles; it may have less need for them, since it often takes insects from the surfaces of leaves.
The family name of “tyrant” flycatchers reflects the aggressive nature of some species, which drive away much larger birds that venture too near their nests. The kingbird group, represented here by the Western Kingbird, provides the best example of this behavior. Seemingly more gentle are the phoebes, soft-voiced flycatchers that often nest near houses or bridges.
Although most flycatchers are dull-colored, a striking exception is the Vermilion Flycatcher, a relative of the phoebes, common along streams in the desert. The male glows red and black, and in his courtship display he puffs himself up like a ball and flutters about the sky while singing madly, in brilliant contrast to the drabness of his relatives.
—Kenn KaufmanTyrant Flycatchers
Representative Sonoran Desert species:
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Northern Beardless-tyrannulet (Camptostoma imberbe)
Vermilion Flycatcher (Pyrocephalus rubinus)
Black Phoebe (Sayornis nigricans)
Say’s Phoebe (Sayornis saya)
Ash-throated Flycatcher (Myiarchus cinerascens)
Brown-crested Flycatcher (Myiarchus tyrannulus)
Western Kingbird (Tyrannus verticalis)
Order: Passeriformes
Family: Tyrannidae (Tyrant Flycatchers)
Spanish names: mosquerito copetón, mosquero (flycatcher)
Distinguishing Features
Northern Beardless-tyrannulet: The smallest flycatcher in the United States, nondescript, gray-olive above and very pale gray below. The name “beardless” refers to the absence of the long rictal bristles at the base of the bill that are characteristic of most flycatchers. Vermilion Flycatcher males: brilliant red head and underparts and black mask, back and wings. Females: streaks on a white breast, brownish head, pale salmon or pink belly. Black Phoebe: Slate black except for white underparts; its fee-bee call is a typical sound along riparian areas in the Southwest. Say’s Phoebe: Pale-gray back, dark tail, and rust-colored underparts. Ash-throated Flycatcher: Brown bushy head, very noticeable whitish-gray throat, light yellow belly, olive-brown back, rust-colored primaries and tail feathers. Brown-crested Flycatcher: Largest of its genus; olive-brown above, black bill, pale gray throat and breast, pale yellow belly; reddish tail and primaries are easily seen in flight. Western Kingbird: gray head, whitish-gray throat and upper breast, pale yellow underparts; the blackish tail has white margins.
Habitat
Northern Beardless-tyrannulet: woodland and stream thickets; found most often in stands of mesquite or cottonwood- willow in southern Arizona. Vermilion Flycatcher: most commonly found near streams or ponds but also frequents grassland and desert habitats with scattered trees. Black Phoebe: prefers shady areas near water including streams, ponds and walled canyons. Say’s Phoebe: Unlike the Black Phoebe, often found in very dry open or semi-open country, far from water; typical of prairies, badlands, and ranch country. Ash-throated Flycatcher: frequents desertscrub, pinyon-juniper, oak groves, creek bottoms, and dry open woodland. Brown-crested Flycatcher: found in association with saguaros; also frequents river groves and other areas where trees are large enough to provide sites for cavity nesting. Western Kingbird: found in semi-open country, farmland, roadsides, and in riparian vegetation.
Feeding
• Diet: Mainly insects
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• Behavior: Unlike other flycatchers which capture insects while flying, the Northern Beardless-Tyrannulet often moves along twigs in search of slow-moving insects. During the summer this species also forages in a more typical flycatcher manner: by flying from its perch and catching insects in its bill.
The Vermilion Flycatcher forages by watching from a perch and either capturing flying insects in the air or hovering and dropping to the ground.
The Black Phoebe is often seen perched over the water, slowly wagging its tail, and then darting out to capture an insect in the air, often just above the water’s surface; occasionally takes small fish.
Because they frequent areas that lack high trees, Say’s phoebes either perch on a low shrub and rock and dart out to capture prey, or hover over fields in search of insects in the grass.
The Ash-throated Flycatcher typically forages by flying out from its perch on a dead upper branch of a tree to hover and pick insects from foliage; seldom takes insects in midair; diet is mostly insects, but spiders, saguaro fruit, elderberries, desert mistletoe berries, and even small lizards, are also eaten.
The Brown-crested Flycatcher typically forages by flying out from its perch to hover and pick insects from foliage; also takes insects in midair or from branches or trunks of trees; will perch in shrubs and cactus to eat fruit; diet is mostly insects, but lizards are also eaten.
The Western Kingbird forages by watching from a perch and then flying out and either snapping up insects midair or taking them on the ground by hovering and diving; diet consists mainly of insects but also includes spiders, millipedes, berries, and fruits.
Life History
Northern Beardless-Tyrannulet: The baseball-sized nest is typically well camouflaged in trees or large shrubs. One to 3 white eggs have small, brown and gray dots. Nesting behavior, incubation details, and development of the young are poorly understood.
Vermilion Flycatcher: The male has a rather showy courtship display that involves fluffing up the feathers while rising vertically in the air and hovering, then swooping back to its perch or fluttering slowly to the female. The nest is built by the female in the horizontal fork of mesquite, willow or cottonwood, and other trees. The nest, which consists of twigs, grass and weeds, is lined with feathers or hairs and is often held together by spider webs. The 2 to 4 heavily spotted cream-white eggs take 14 to 15 days to incubate. Only the female incubates the eggs but both parents feed the young until they fledge at 14 to 16 days.
Black Phoebe: The male’s courtship display includes fluttering in the air with rapidly repeated calls, then descending slowly. Black phoebes are solitary nesters that often return to their nest site year after year. The nest is made of mud, grass, and weeds and is usually found in a sheltered spot such as a cliff face or on the support strut of a bridge. Three to 6 eggs are incubated by the female and hatch in 15 to 17 days. The young, which are fed by both parents, leave the nest about 2 to 3 weeks after hatching.
Say’s Phoebe: The nesting site varies greatly—it may be on a rocky ledge, under the eaves of a barn, under a bridge, or even in a well or mine shaft. The nest is made of grass, weeds, twigs, wool, moss, spider webs, and other materials. Unlike the Black Phoebe, no mud is used in its construction. Three to 7 eggs take 12 to 14 days to incubate. Both parents care for the nestlings. The young leave the nest 14 to 16 days after hatching. These birds are not shy of people and adapt well to changes to their natural landscape; populations appear to be stable.
Ash-throated Flycatcher: The nest is usually in a cavity or in an existing hole, but may also be found in a variety of other—often unlikely—places like mailboxes and exhaust pipes. The nest consists of a mass of grass, hairs, weeds, and twigs lined with softer material. Three to 7 creamy- or pinkish-white, blotched or streaked eggs are incubated by the female and hatch in about 15 days. Both parents feed the nestlings, which are ready to fly 14 to 16 days after hatching.
This species will use nest boxes put out for bluebirds.
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Brown-crested Flycatcher: This species is aggressive and conspicuous during nesting season. They arrive after most other hole-nesting birds and therefore may have to compete for nest sites. The site is in a cavity in a tree or giant cactus, usually in holes excavated by woodpeckers. Both sexes help with the construction of the nest in the cavity. Plant fibers, hair, feathers, and other debris are used. Three to 6 white to pale buff blotched eggs are incubated by the female. Young hatch in 13 to 15 days. Both parents feed the nestlings and first flight takes place 12 to 18 days after hatching.
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Western Kingbird: Nest sites vary and may include tree limbs, utility poles, cliff ledges, and abandoned nests of other birds. Grass, weeds, twigs, plant fibers and softer material for the lining are used in the construction of the cup-shaped nest. Three to 5 white and heavily blotched eggs take 18 to 19 days to hatch. This spunky bird will harass hawks or other large birds that stray too close to its nest. After the young fledge, typically 18 to 19 days after hatching, it is not uncommon to see 6 or more kingbirds burst out of a tree in search of insects.
The Kingbird has adapted well to human encroachment. It has expanded its breeding range and increased its numbers during the 20th century.
Swallows
 | Swallows spend their days mostly in the air, often in flocks, plying the skies in search of the flying insects that make up the majority of their diet. With their graceful flight, musical voices, and sociable nature, these birds are popular with humans—and, it seems, the reverse is also true. Many kinds of swallows have prospered by learning to live alongside civilization. |
The biggest concentrations of swallows occur where there are swarms of flying insects, especially over water. Therefore, swallows are less numerous in the desert than in many other habitats. A few species are common here, however. Widespread but unobtrusive is the Northern Rough-winged Swallow, a brown bird that digs nesting tunnels in the vertical walls of dry arroyos and road cuts. Less sociable than most, it usually forages and nests in isolated pairs.
At one time, Cliff Swallows were quite localized in the Southwest. They required soft mud with which to build their gourd-shaped nests, and vertical or overhanging cliffs on which to place them. Modern civilization gave them an abundance of new sites: buildings close to watered lawns, and bridges over muddy creeks. Today Cliff Swallows are common in summer around many towns and roads in desert regions.
A true desert dweller is the local race of the Purple Martin, which nests in holes in saguaro cacti. Purple Martins in eastern North America today nest almost exclusively in multi-roomed birdhouses put up for them, but this habit has not yet caught on in the Southwest—our local martins are more independent of humans than are any other swallows here.
—Kenn KaufmanSwallows
Representative Sonoran Desert Species:
Purple Martin (Progne subis)
Northern Rough-winged Swallow (Stelgidopteryx serripennis)
Cliff Swallow (Hirundo pyrrhonota)
Order: Passeriformes
Family: Hirundinidae (Swallows)
Spanish names: golondrina (swallow)
Distinguishing features
Purple Martin: Largest swallow in North America; tiny bill, forked tail. Adult male: black with some purple iridescence, deeply forked tail. Adult female: dark gray upperparts with some purple, whitish-gray underparts with some speckling. Northern Rough-winged Swallow: Light brown above and white underparts, small bill, forked tail, brownish throat and chest. Cliff Swallow: Blackish cap, light spot above tiny bill, buff- colored rump, squared-off tail, whitish belly and rust-colored throat and cheek.
Habitat
Purple Martins are found in semi-open country near water, saguaro forest, and woodlands. Northern Rough-winged Swallows live near water, including streams, lakes, and riverbanks; also found in desert washes. Cliff Swallows are found in a variety of open to semi-open areas, especially when these areas are near water.
Feeding
• Diet: All 3 species feed on a wide variety of insects; spiders and other arthropods are also taken.
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• Behavior: These birds do nearly all of their foraging in the air. Their short, wide bills are ideally suited for snatching insects out of the air. They are often seen flying over water because of the abundance of insects. During bad weather these birds may resort to foraging on the ground.
Life History
Purple Martin: It uses naturally occurring sites, such as woodpecker holes in trees or saguaros. In eastern North America, most Purple Martins today nest in multi-roomed birdhouses put up to attact them.The cup-shaped nest, which is made by both sexes, consists of grass, twigs, leaves, feathers, and often mud. Whitish eggs (3 to 8) are incubated by the female and hatch in 15 to 18 days. The young leave the nest 26 to 31 days after hatching. Purple Martin numbers have been declining; the reasons are not well understood but may be due to competition with starlings.
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Northern Rough-winged Swallow: Unlike many species of swallows, this bird tends to nest singly. For nesting, the Rough-wings dig horizontal burrows in dirt stream banks, arroyo walls, or road cuts. They will also sometimes use holes in man-made structures. The bulky nest is made of weeds, twigs, and other vegetable matter. Four to 8 white eggs hatch in 12 to 16 days. Both parents feed the nestlings; young leave the nest 19 to 21 days after hatching. Because Rough-winged Swallows take advantage of man-made structures and areas of ground disturbance for nesting sites, they have actually benefited from the advance of civilization.
Cliff Swallow: This species most often uses elevated vertical surfaces with a protective overhang for nesting sites. Typical sites include cliff faces, buildings, and bridges. The gourd-shaped nest is made of mud and may be lined with feathers and possibly vegetable matter. Old nests are sometimes reused. Three to 6 white to pale pink spotted eggs are incubated by both parents and hatch in 14 to 16 days. The young leave the nest 26 to 31 days after hatching. This species nests in colonies of up to several hundred individuals.
Eggs
The egg of a bird consists of several parts. The yolk is a single giant cell, the true egg or ovum, produced in the ovary of a bird. The yellow material is mostly food for the growing embryo once the egg is fertilized. The ovum is released from the ovary and picked up by the oviduct where it is fertilized by sperm from a recent mating. As the ovum travels down the oviduct, layers of material are added in an assembly line fashion. First several layers of albumen (egg “white”), then two egg membranes, then the shell, and finally coloring. Most birds will lay one egg per day until they have a complete set. This set of eggs is called a clutch.
The color of the egg is related to its need to be camouflaged. Cavity nesters usually lay all white eggs since they are out of sight. Ground nesters lay brown, gray, or olive colored eggs, the color of the surrounding vegetation. Tree nesting birds will lay white or blue eggs, splotched or speckled with brown, to help conceal them in dappled light.
Common Raven
Members of the corvid family, including ravens, crows, jays, and magpies, are thought to be among the most intelligent of birds. If adaptability is any sign of intelligence, then the Common Raven must rank as a superstar: it thrives from Siberia to North Africa, from arctic Alaska to the mountains of Central America. Forest, tundra, and desert are all within its realm. Technically it is classed as one of the songbirds, or perching birds, but it is larger than many hawks, and it will feed as a predator or scavenger as the opportunities arise.
In the southwestern U.S. and northern Mexico, Common Ravens range from sea level (along the Gulf of California) to the mountaintops. They can even be seen flying over desert cities, their croaking calls floating down from the sky as the big birds flap overhead. Unlike the Chihuahuan Raven—a smaller and more sociable bird that lives in grasslands along the eastern edge of our region—Common Ravens seldom travel in flocks, but members of a pair may stay together at all seasons. Their nesting sites are sometimes in large trees, where these are available, but most raven nests in the Sonoran Desert are placed on high cliffs.
—Kenn KaufmanCommon Raven (Corvus corax)
Order: Passeriformes
Family: Corvidae (Crows, Jays, Magpies)
Spanish names: cuervo grande, cuervo holárctico
Distinguishing features
A hawk-sized, shiny, black bird with a black bill and a wedge-shaped tail. The Common Raven is the largest member of the order Passeriformes (the songbirds, or perching birds).
Habitat
This intelligent and very adaptable bird occurs from low deserts to mountains, over open desert areas to dense forests.
Feeding
• Diet: Omnivorous; diet may include carrion, reptiles, amphibians, bird eggs, insects, and plant matter.
• Behavior: Opportunistic feeders, ravens often take food wherever it can be found, including public landfills; also frequently search for nests where they feed on the eggs; sometimes hunt in pairs where one bird flushes out the prey. Their water-rich diet of carrion, insects, and eggs, along with their stocky bodies, which help them better regulate their body temperature, allow this species to cope with the desert’s heat.
Life History
Courtship involves the male soaring, swooping and tumbling in front of the female. The pair also soar together, then perch and preen one another. Ravens mate for life.
Nesting takes place from February to May in this region. The nest, which is usually built hight in a tree or on a precipice, is a platform made of large sticks, twigs and vine stems with a deep depression in the center; it is lined with grasses, animal hair and mosses. Usually 4 to 6 greenish blotched eggs are laid; incubation is by the female. The male feeds the female during the 3 week incubation period. The young are altricial; they leave the nest about 5 weeks after hatching.
A Matter of Style
The folklore of more than one group of native Americans includes stories about coyote and raven interactions. I witnessed such an encounter early one morning while walking the banks of the Rillito River near Tucson. Two ravens were in the center of the dry riverbed, actively complaining. About five feet from them was a coyote, nose to the ground, casually sniffing about. Evidently located between the two groups was an object—possibly a bit of food—that all three coveted.
The ravens asserted themselves through noise and occasionally hopping about, but never getting too close to the canine. The coyote’s approach to the matter was completely the opposite: he simply did not acknowledge the birds’ presence. He never looked at them. He made no move in their direction. One could almost hear him mutter, “I don’t see anything. Do you see anything? I don’t see anything.”
Eventually the coyote trotted down the riverbed, apparently oblivious to the ravens’ continued harangue. It seemed as though both coyote and ravens had forgotten whatever object it was that had sparked the debate, the coyote possibly believing he was the victor in this confrontation by his superior demeanor, and the ravens believing they were the winners by raucous strength of voice.
—Peggy Larson, naturalist and author
