Wood Warblers
Often referred to as the “butterflies of the bird world,” wood warblers are very small, active, and colorful. They flit through the foliage from the treetops to the understory in search of small insects. More than fifty species occur in North America; almost all are migratory, and many spend the summer in northern coniferous forest and the winter in tropical rainforest.
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Since these birds are lovers of trees and foliage, it is not surprising that the warbler family is under- represented in the desert. A few species, like the Yellow Warbler and the Yellow-breasted Chat, spend the summer in the dense habitats along southwestern rivers. In winter, Orange-crowned Warblers may forage quietly in the undergrowth of those same riparian thickets. Yellow-rumped Warblers, hardy little birds that arrive to spend the winter throughout the lowlands of the Southwest, are sometimes common along rivers and in dense mesquite bosques in the desert. Several other warbler species may stop through in migration. There are times in late spring and early fall when bright golden- yellow Wilson’s Warblers seem to flit along every wash in the desert.
Of all this diverse family the only species truly adapted to the desert is Lucy’s Warbler, a pallid gray-and-white sprite with touches of chestnut in the plumage. Lucy’s Warblers arrive from Mexico quite early in spring, and soon the bright, simple songs of the males can be heard everywhere among the mesquite trees.
—Kenn KaufmanWood Warblers
Representative Sonoran Desert species
Orange-crowned Warbler (Vermivora celata)
Yellow-rumped Warbler (Dendroica coronata)
Wilson’s Warbler (Wilsonia pusilla)
Yellow Warbler (Dendroica petechia)
Yellow-breasted Chat (Icteria virens)
Lucy’s Warbler (Vermivora luciae)
Order: Passeriformes
Family: Parulidae (Wood-Warblers)
Spanish names: gusanero, chipe
Distinguishing Features
Orange-crowned Warbler: Olive-green upperparts, orange crown patch (rarely visible), olive-yellow underparts, broken eye ring, no wing bars; lack of conspicuous markings is a good aid in identification.
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Yellow-rumped Warbler male: bright yellow cap, throat and rump, broken eye ring, yellow patch at side of breast, white underparts; female: similar but duller, yellow on throat less distinct.
Wilson’s Warbler: Yellow head and underparts, olive upperparts, males have distinct black cap. Yellow Warbler: Overall yellow plumage, upperparts greenish-yellow.
Yellow-breasted Chat: The largest warbler, distinct white eye rings, bright yellow throat and breast, olive-brown upperparts, thick bill.
Lucy’s Warbler: White below, pale gray above, pale face with suggestion of eye-ring; reddish brown spot on crown and patch on rump, more obvious on adult male.
Habitat
Orange-crowned Warbler prefers riverside or shrubby vegetation, chaparral, gardens, and parks. Yellow-rumped Warbler inhabits streamside woodland in our region. Wilson’s Warbler frequents thickets along streams, scrubby clearings, moist tangles. Yellow Warbler is found in streamside habitats, especially cottonwood-willow groves in our region. Yellow-breasted Chat frequents streamside thickets, meadows with tall shrubs, woodland edges. Lucy’s Warbler prefers mesquite bosques and edges of riparian woods in desert zones.
Feeding
• Diet: The Yellow, Wilson’s and Lucy’s Warblers feed almost entirely on insects; the other species feed primarily on insects but also eat some berries.
• Behavior: It is not uncommon for two or more species of warblers to exist in the same habitat and feed on the same kinds of insects. They cope with competitive pressure by foraging in slightly different ways. Orange-crowned Warbler forages by flitting from branch to branch or hovering in search of insects on foliage; will also take insects midair.
Yellow-rumped Warbler forages by hovering and taking insects from foliage, taking insects midair, searching among twigs, and searching through ground litter.
Wilson’s Warbler forages by hopping about on branches, tree trunks, and on the ground; also catches insects midair. Yellow Warbler behavior is similar to Orange-crowned Warbler.
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Yellow-breasted Chat forages by moving about in dense vegetation; perches to eat berries; unlike other warblers it holds its food in one foot while eating. Lucy’s Warbler hops about actively in trees and shrubs, seeking insects on the twigs and foliage.
Life History
These tiny, colorful, active birds are found only in the New World. Many tropical warblers are not migratory. All of ours are, but they occur here at different seasons. Orange-crowned is present mostly September to May, and Yellow-rumped mainly October to April (they winter here). Wilson’s, a migrant, occurs in Spring and Fall. Lucy’s and Yellow Warblers nest here, and are present mainly March to September; Yellow-breasted Chat also nests, and is present mainly May to September.
In spite of their name, warblers are not particularly well known for the musicality of their voices. The exception, however, is the Yellow-breasted Chat. Its song consists of an odd assortment of whistles, chucks and hoots.
Most warbler nests are open cups made of leaves, twigs, weeds, and other vegetable matter with a lining of finer material. Wilson’s and Orange-crowned Warbler nests are on the ground; the others make their nests in forks or on horizontal branches of trees and shrubs. Lucy’s Warbler is one of only two members of the family to nest in holes in trees; it also sometimes builds its nest behind a piece of loose bark. The female is usually responsible for both nest building and incubation. The female lays 3 to 6 eggs that are usually white with brownish spots. Incubation with these species ranges from 10 to 13 days. Both parents feed the young. The young leave the nest 8 to 13 days after hatching.
The Wilson’s Warbler, Yellow Warbler, and Yellow-breasted Chat are frequently parasitized by cowbirds. When this happens to the Yellow Warbler it may either build a new nest on top of the cowbird eggs or abandon the nest altogether.
Tanagers
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Most tanagers are multi-colored birds of tropical forest. There are places in South America, in the foothills of the Andes, where flocks of small birds may include a rainbow palette of a dozen species of tanagers. Only a few species are found north of the Mexican border. In the Sonoran Desert they have only a marginal presence, but their bright colors make them conspicuous when they do appear.
Summer Tanagers in eastern North America inhabit oak woods, but in the west they are mostly streamside birds. Where desert rivers still have good stands of cottonwoods, Summer Tanagers are common throughout the warmer months. Since they keep to the treetops, they are not easy to see, but their crackling call notes and lazy, burry songs are familiar sounds.
Western Tanagers nest only in coniferous forests of the high mountains and the north, so they might seem most unexpected in the desert. Every year during migration, however, many appear throughout the lowlands. There are days in May and again in early fall when Western Tanagers seem to be scattered all over the desert, and the striking yellow-and-black males look oddly out of place—which they are. Before winter weather sets in, they will have retreated to tropical climates with more typical tanager habitat.
—Kenn KaufmanTanagers
Representative Sonoran Desert species:
Summer Tanager (Piranga rubra)
Western Tanager (Piranga ludoviciana)
Order: Passeriformes
Family: Thraupidae
Spanish names: piranga avíspera, cardenal avíspero
Distinguishing features
Summer Tanager: Full-plumaged males are rose red; females and young are yellowish or olive-green; often mistaken for Cardinals, but lack crests (the only all-red non-crested bird to occur in tall riparian communities). Western Tanager: Adult male has a bright red head, yellow body, and black tail, back and wings; wings have white bars; female is dull green above.
Habitat
Summer Tanagers frequent streamside cottonwood and willow groves in the southwestern U.S. and open woodlands and oak groves elsewhere. The colorful Western Tanager lives in open conifer or mixed forests of the north and high mountains. During migration it may frequent any habitat, including desert and grassland.
Feeding
• Diet: Insects and small fruits.
• Behavior: Both species forage in the tops of trees where prey is taken from the foliage; insects also taken midair. Summer Tanagers may take prey from leaves while hovering; also known to raid wasp nests for larvae. Western Tanagers take frequent trips to flowers, possibly for both nectar and insects.
Life History
Summer Tanager: This species is present in southern Arizona only during the summer, when it nests in willow, cottonwood, or sycamore groves in canyons up to about 5000 feet. It usually lays 4 pale bluish-green spotted eggs in a shallow cup-shaped nest of plant fibers placed on a horizontal limb of a large tree. The female incubates the eggs for 11 to 12 days and is assisted by the male in feeding the nestlings.
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Western Tanager: The nest is usually placed in the fork of an outer limb of a coniferous tree. The woven, cup-shaped nest is made of twigs, grass, bark strips, and rootlets. Bluish-green eggs (3 to 5) with brown blotches hatch in about 13 days. The young leave the nest about 14 days after hatching.
Feather Molt
Birds periodically molt their old feathers and replace them with new ones. The purposes of feather molt are to replace worn feathers, to change into or out of courtship plumage, or, maybe, to improve hygiene. The timing and frequency of molts are very important. Each species has its own pattern. One common pattern consists of a partial body molt before the breeding season to bring a bird into courtship color, then a complete molt of all the feathers, including flight feathers, after breeding and before migration. Feathers are usually molted in a gradual pattern, so that the bird does not lose its ability to fly or to protect its body from the elements.
Cardinals & Grosbeaks
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The Northern Cardinal is among the most popular garden birds in eastern North America, chosen as the official state bird of seven eastern states. Travelers are often surprised to discover that, in the very different surroundings of the Sonoran Desert, the same cardinal is abundant—along with several other related birds.
All the members of this group have thick bills, good for crushing hard seeds, which make up a high percentage of their diet at some seasons; most of them switch over to eating mainly insects during the nesting season. In all of our species, the males have bright colors and rich whistled songs. When they are not singing, they often hide their colors amidst dense foliage.
Very closely related to the cardinal is the Pyrrhuloxia. The male Pyrrhuloxia is mostly gray, with its red reduced to accents and highlights, but otherwise it and the cardinal are remarkably similar; some of their whistled songs are essentially identical. The two species live side by side in dense brush along desert washes, but the Pyrrhuloxia also ranges out into more open and arid places.
At the other end of the spectrum from these red birds are the Varied Bunting (mostly dark purple) and the Blue Grosbeak, mainly summer residents in the Sonoran Desert. Another species, the Black-headed Grosbeak, is mostly a denizen of oak woods in summer, but migrants show up all over the desert in spring and fall.
—Kenn KaufmanCardinals and Grosbeaks
Representative Sonoran Desert species
Northern Cardinal (Cardinalis cardinalis)
Pyrrhuloxia (Cardinalis sinuatus)
Blue Grosbeak (Guiraca caerulea)
Black-headed Grosbeak (Pheucticus melanocephalus)
Varied Bunting (Passerina versicolor)
Order: Passeriformes
Family: Cardinalidae
Spanish names: cardenal comun, chivo (Northern Cardinal), cardenal pardo, cardenal torito (Pyrrhuloxia)
Distinguishing Features
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Northern Cardinal: The male is red with a reddish bill and black face. The young males have black bills. The female is light brown or tan and red with a red bill and crest. The female is commonly mistaken for a male Pyrrhuloxia, but the Cardinal female has a red bill as opposed to the ivory bill of the Pyrrhuloxia, and the Pyrrhuloxia is grayer.
Pyrrhuloxia: About 7¼ inches (19 cm) in length, the male is a slender grayish-tan and red bird with a crest and a small stubby, almost parrot-like bill. The rose-colored breast and crest suggest the female Cardinal, but the gray back and ivory-colored bill set it apart. The female has a gray back, buff breast, a touch of red in the wings and crest and an ivory-colored bill.
Blue Grosbeak: This bird measures 6 to 7¼ inches (15 to 19 cm). The adult male is dark blue with 2 rust-colored wing bars. The female is dull brown with buff wing bars. As with other grosbeaks, this species has a heavy, conical bill.
Black-headed Grosbeak: This grosbeak measures 6¼ to 7¼ inches (17 to 19 cm). The adult male has a black head, brownish-orange underparts, and black wings with white wing bars. The female has a striped head, streaked back and sides, and sparsely streaked buff-colored breast. The heavy, conical bill is pale in both sexes.
Varied Bunting: This attractive bunting measures 4¼ to 5¼ inches (11 to 14 cm). The adult male has a plum or red-purple body, a blue crown, and a bright red patch on the back of the head. In poor light the bird looks black. Females and immatures are unstreaked gray-brown above and buffy below.
Habitat
The Northern Cardinal covers a large range, from southern Ontario to the Gulf states, and from the southwestern United States to Belize and Guatemala. In Mexico, it is a resident of central and southern Baja California. It is widespread from the northern states to the Isthmus of Tehuantepec and east through the Yucatan peninsula. It prefers wood-land edges, mesquite thickets and stream edges.
Pyrrhuloxias occur from the borders of Arizona, New Mexico, and Texas southward to central Mexico and central and southern Baja California. They frequent mesquite, thorn scrub and deserts.
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The Blue Grosbeak is found generally in the southern half of the United States south to Central America. It winters from northern Mexico to Panama. This bird inhabits brush, streamside vegetation, roadsides, and overgrown fields. In the southwest U.S., this species is most often found near water in streamside thickets or mesquite bosques.
The Black-headed Grosbeak is found from southern British Columbia and Saskat-chewan, through the western half of the United States, south to its wintering grounds in western Mexico. This bird inhabits foothills and dense riverside wooded areas. It breeds mainly in deciduous and mixed woods such as cottonwood and willow groves, pine-oak and pinyon-juniper woodlands. In migration its habitat includes open woods, riparian areas, mesquite bosques, desert washes, and even suburban areas.
The Varied Bunting is found from the extreme southern parts of Arizona and New Mexico and southwestern Texas south into Mexico. Most of these birds migrate a short distance into Mexico during winter. This bird inhabits dense and thorny habitat, streamside thickets, and open desert if there is dense brush available.
Feeding
• Diet: All species feed on insects, berries, and seeds; Blue Grosbeak adds spiders, snails, and plant parts to its diet; Black-headed Grosbeak includes spiders and snails. It is able to feed on Monarch butterflies in spite of the noxious chemicals they exude.
• Behavior: The Blue Grosbeak forages on the ground and from plants; it also flies out to catch insects midair or hovers and removes them from foliage. This species commonly forages in flocks during winter and migration, but not in the breeding season.
Black-headed Grosbeak forages by hovering and taking prey from the foliage of shrubs and trees and by flying out to catch insects midair.
The diet of the Varied Bunting is not well known, but probably consists of seeds, insects, and some berries. Insects are probably taken from leaves, and seeds from the ground. This species forages in flocks during winter.
Life History
Northern Cardinal: Nesting begins from late March to early April. The cup-shaped nest of twigs and plant stems is lined with grasses and hairs. It is located 5 to 10 feet (1.5-3 m) high in dense shrubbery or mesquites. There are usually 3 to 4 eggs that are incubated for 12 to 13 days. The altricial young leave the nest at about 10 days. Cardinals typically raise 2 to 3 broods per year.
Pyrrhuloxias begin nesting from mid March to early April. The nest is a compact cup of twigs lined with grasses and hair, located 5 to 8 feet (1.5-2.5 m) above ground in a forked branch or against the main trunk of a mesquite or other tree. The 2 to 5 eggs are incubated for 14 days and the altricial young leave the nest at 10 days.
Blue Grosbeak: The open cup-shaped nest is usually rather low in shrubs and trees. It is made of twigs, weeds, leaves, bark, and rootlets with a lining made of finer material such as fine grass and animal hair. Other items, such as pieces of fabric, string, or paper are also often incorporated into the nest. There are 3 to 5 pale blue eggs that take about 12 days to hatch. The nestlings, which are fed entirely by the female, leave the nest about 10 to 12 days after hatching. The male may begin to feed the young after they fledge, thus allowing the female to begin a second brood.
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Black-headed Grosbeak: This male’s courtship display involves flying above the female with wings and tail spread open and singing. The bulky, open cup-shaped nest is built by the female in trees or large shrubs. It is made of twigs, weeds, pine needles, and rootlets with a lining made of finer material such as fine grass and animal hair. Two to 5 pale greenish blue eggs with reddish brown spots are incubated by both parents. The young take about 12 to 14 days to hatch. The nestlings are able to fly about a month after hatching but remain nearby to be fed by their parents.
Varied Bunting: The nest, which is built by both parents, is a compact open cup made of grass, weeds, and plant stems lined with finer material. It is typically located in the crotches of dense shrubs or trees. Bluish-white eggs (3 to 5) are incubated by the female in 12 to 13 days. The young leave the nest after 12 days. Shortly after fledging occurs the male may take on the responsibility of feeding half the brood thus allowing the female to attempt another nesting. In Arizona the varied bunting’s nesting is timed to summer rains.
Sparrows
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Most people, at the mention of sparrows, think first of the House Sparrow. That bird is familiar enough—it thrives in urbanized areas, including southwestern cities—but it belongs to a family that is native to the Old World. The sparrows that occur naturally on this continent are a much more diverse group, many with distinctive patterns and musical songs. All of them have short thick bills—designed for cracking open seeds, a major part of their winter diets— but all eat many insects as well, especially in warm weather.
The ultimate dryland sparrow is the Black-throated Sparrow, a smartly patterned bird that thrives year-round in the Sonoran Desert and also in the much sparser plant growth of the Chihuahuan Desert farther east. However, several other species are permanent residents around the edges of this habitat. Song Sparrows (of a distinctive local form, paler and redder than Song Sparrows elsewhere) are common along desert rivers where there is still healthy riparian growth. Rufous-winged Sparrows survive in desert patches that have escaped the effects of overgrazing, while Rufous-crowned Sparrows haunt rocky canyons and foothills. The towhees, big sparrows that forage by scratching actively on the ground, are represented by Abert’s Towhees along lowland rivers and Canyon Towhees on drier slopes.
Winter is the season when sparrow diversity peaks, as more species move in from the north. Flocks of White-crowned Sparrows range along the brushy arroyos, flocks of Brewer’s Sparrows are common on the more open flats, and several other species appear as well. Because they feed largely on seeds at this season, their numbers vary: if the summer and fall rains have produced a good crop of annual weed and grass seeds, the winter desert may be alive with sparrows.
—Kenn KaufmanSparrows
Representative Sonoran Desert species:
Rufous-winged Sparrow (Aimophila carpalis)
Rufous-crowned Sparrow (Aimophila ruficeps)
Brewer’s Sparrow (Spizella breweri)
Black-throated Sparrow (Amphispiza bilineata)
Sage Sparrow (Amphispiza belli)
Song Sparrow (Melospiza melodia)
Lincoln’s Sparrow (Melospiza lincolnii)
White-crowned Sparrow (Zonotrichia leucophrys)
Order: Passeriformes
Family: Emberizidae (Buntings and their relatives)
Spanish names: gorrión, zacatero
Distinguishing Features
Rufous-winged Sparrow: Pale gray below, brown above with small rusty spot on shoulder; gray face with rusty stripes on crown and behind eye, 2 short black whisker stripes below bill.
Rufous-crowned Sparrow: Gray-brown above, gray below, with rusty crown and single heavy black whisker stripe below bill.
Brewer’s Sparrow: Very plain, small, and relatively long-tailed; sandy-brown above with narrow black streaks on back and crown, brown ear patch, plain pale gray below.
Black-throated Sparrow: Black throat and mask; white eyebrow and malar (chin) streak; gray crown, back, and wings; white belly; dark bill.
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Sage Sparrow: White spot above the bill; white throat with black whisker; gray crown, back and wings; white on outer tail feathers; dark bill.
Song Sparrow: Brown streak extending behind eye, thick white streak below bill, brown wings with some rust, underparts white with heavy dark streaks and central breast spot.
Lincoln’s Sparrow: Brown crown with central gray stripe, gray face and eyebrow, buffy breast and flanks with fine streaks, white belly.
White-crowned Sparrow: Black and white head stripes, gray face and underparts, tan back with dark streaks, pink bill.
Habitat
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Rufous-winged Sparrow: Desert grass mixed with brushes, mesquite, cholla. Rufous-crowned Sparrow: Grass or bushy vegetation, often near rocky slopes or outcrops. Brewer’s Sparrow: Open desert, especially creosote flats (winter). Black-throated Sparrow: Found mainly in desert thornscrub and dry, open habitats such as creosote and sagebrush flats. Sage Sparrow: Deserts and open brushy flats (winter). Song Sparrow: Inhabits mainly streamside and low, dense brushy areas in the Sonoran Desert region. Lincoln’s Sparrow: Areas with dense vege-tation and overgrown fields (winter). White-crowned Sparrow: Desert washes, ranches, gardens, parks, and along streams.
Feeding
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• Diet: Sparrows in the Sonoran Desert region feed mostly on insects and seeds.
• Behavior: Rufous-winged Sparrow forages mainly by hopping around on the ground, occasionally taking insects midair; feeding takes place in pairs or in family groups.
Rufous-crowned Sparrow forages by walking or hopping slowly on the ground or in low bushes; usually found foraging in pairs or in family groups.
Brewer’s Sparrow forages on the ground or in low vegetation usually in flocks.
Black-throated Sparrow forages by moving around on the ground or in desert trees and other vegetation; occasionally catches insects midair.
Sage Sparrow forages mainly on the ground where it is sometimes seen scratching the soil to turn up food items; forages in flocks when not nesting.
Song Sparrow forages mainly on the ground but also feeds in trees and shrubs; will come to feeders if they are in good cover.
Lincoln’s Sparrow forages by hopping on the ground near or under denser vegetation.
White-crowned Sparrow forages mainly by hopping or running around on the ground, occasionally taking insects midair; forages in flocks when not nesting.
Life History
Because of their generally brownish and often nondescript coloring, identifying sparrows can be a difficult and often unrewarding exercise for the beginning birder. But with a little persistence the birder can learn to recognize these species by their intricate markings and often engaging songs.
All of the sparrows mentioned here live near the ground or very close to it. The majority nest as isolated pairs and aggressively defend their nesting areas by driving away intruders of their own species.
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The females of most of the species mentioned here are responsible for nest building. Cup-shaped nests made of twigs and weeds are located in dense low-growing brush or cacti, or on the ground. A range of from 2 to 5 eggs, which may be plain or spotted, are most often incubated by the female only; usually both parents share in feeding the young. Rufous-winged and rufous-crowned young leave the nest 8 to 9 days after hatching; the other species leave typically between 9 and 12 days after hatching.
Towhees
Representative Sonoran Desert species:
Canyon Towhee (Pipilo fuscus)
Abert’s Towhee (Pipilo aberti)
Green-tailed Towhee (Pipilo chlorurus)
Order: Passeriformes
Family: Emberizidae
Spanish names: vieja, viejita, ilama, toqui de Abert (Abert’s Towhee),
toqui cola verde (Green-tailed Towhee)
Distinguishing Features
Canyon Towhee: This is a large sparrow-like bird, about 8¼ inches (21.6 cm) long. Both sexes are similar in appearance, with rusty undertail coverts and a touch of rust on the crown. It is usually found in pairs in southern Arizona and adjacent Sonora, but is not always easily seen. Abert’s Towhee: A large (9 inches in length; 23 cm), fluffy, buff-brown bird with black feathers edging the bill. Both sexes look alike. It can be distinguished from the brown towhee by its richer brown color and black on the face. Green-tailed Towhee: About 6¼ to 7 inches (16.5 to 18 cm) in length, this bird has a plain olive-green back, rufous crown, a conspicuous white throat, and a gray breast. The rufous crown and the white throat are the best identifying marks. The tail is relatively long and prominent. The bill is black.
Habitat
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Canyon Towhee: A characteristic Sonoran desert bird; a common resident ground-dwelling bird, it prefers scrubby desert areas, foothills and canyons.
Abert’s Towhee: Common in southern Arizona where it is restricted to thickets near water; it frequents thickets or mesquite bosques along streams or irrigation canals in low desert areas.
Green-tailed Towhee: Prefers arid, brushy foothills and mountain slopes, the more open pine forests, and chaparral.
Feeding
• Diet and Behavior: All 3 species feed on seeds and insects found on or near the ground.
Life History
The Canyon Towhee weaves a cup-shaped nest of plant leaves and fibers, usually 6 to 15 feet high in a shrub or tree (sometimes in mistletoe clumps). The female incubates the 3 or 4 bluish-green eggs for about 11 days. The young fledge in 8 to 9 days. If the nest is approached, the female, like other towhees, drops straight to the ground and runs away in mouselike fashion, probably as a distraction.
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Abert’s Towhee lays 3 to 4 eggs in a bulky cup-shaped nest woven of plant fibers and placed low in a tree or shrub. It is a common cowbird host; its future is threatened by cowbird impact and disappearance of desert riparian habitat.
Green-tailed Towhee builds a deep, cupped nest of twigs, grasses, and stems and lines it with small roots and hair. It is built near the ground in dense foliage. Usually 4 spotted eggs are laid.
Dark-eyed Junco (Junco hyemalis)
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Order: Passeriformes
Family: Emberizidae
Distinguishing Features
This bird is 5 to 6½ inches (13 to 16 cm) in length, with considerable geographic variation in plumage: all have white outer tail feathers, dark hood, and pale belly, but back and sides vary from gray to reddish-brown.
Habitat
The Dark-eyed Junco inhabits the edges of woodlands or conifer forests throughout its range. In the Sonoran Desert this species occurs only in winter where it inhabits semi-open areas including roadsides, brushy spots, parks, and suburban gardens.
Feeding
• Diet: Mostly seeds and insects but also eats small berries.
• Behavior: Forages mainly by running or hopping on the ground. Tends to feed on spilled seed under bird feeders. Also seen moving through the branches of trees or shrubs.
Life History
During nesting season the male sings from a high perch to defend his territory. Both birds may droop their wings and spread their tail feathers during courtship displays. The nest is usually on the ground in a well-hidden and protected spot, although it can also be located in shrubs, trees, or building overhangs. The female makes a cup-shaped nest out of grass, weeds, leaves, and twigs and lines it with finer material such as hair and grass. The 3 to 6 bluish-white eggs have blotches concentrated on the large end. Incubation by the female takes 11 to 13 days. Both parent birds feed the nestlings. The young leave the nest 9 to 13 days after hatching.
This species is migratory, although some birds in the mountains of southwestern United States are permanent residents.
Blackbirds & Orioles
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The blackbird family is hard to characterize because it includes such diverse types: orioles, meadowlarks, grackles, cowbirds, and others. Most have at least some black in the plumage, and their other colors run to warmer tones, such as yellow, brown, and orange. All the species have sharply-pointed bills. Most are more or less omnivorous. None is adapted to extreme desert conditions, but several species make inroads to the Sonoran Desert.
Orioles in general are treetop birds, moving methodically through the foliage in search of insects, often stopping at flowers to add some nectar to their diet. In the lowlands of the Southwest, hooded orioles and Bullock’s Orioles occur mainly as summer residents in riverside woodlands. The Hooded Oriole has a special liking for palms, however, and it may be common in desert cities where palms have been planted.
Great-tailed Grackles are recent arrivals in this region. Spreading north through Mexico, they did not reach Arizona until 1936. Even today they are closely associated with water, living near riversides, ponds, irrigated farmland, or watered lawns. Sociable birds, they nest in colonies and sleep in large communal roosts, where their cacophonous voices make them a little too conspicuous for some tastes.
Cowbirds’ nesting behavior—or lack of it—makes them the most unpopular of the blackbirds and, perhaps, the most interesting. Cowbirds lay their eggs in the nests of other birds, leaving the unwitting hosts to hatch the eggs and feed the young. In many cases, only the young cowbirds survive. Cowbirds are seldom seen in natural desert areas in winter, when they mostly forage in agricultural land; but in the breeding season, Brown-headed Cowbirds and Bronzed Cowbirds infiltrate the desert (and most other habitats), seeking nests to parasitize.
—Kenn KaufmanBlackbirds
Representative Sonoran Desert species:
Great-tailed Grackle (Quiscalus mexicanus)
Bronzed Cowbird (Molothrus aeneus)
Brown-headed Cowbird (Molothrus ater)
Order: Passeriformes
Family: Icteridae (Blackbirds and Orioles)
Spanish names: zanate, chanate (Great-tailed Grackle); tordo (Cowbird); tordo ojirojo, tordo mantequero (Bronzed Cowbird)
Distinguishing Features
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Great-tailed Grackle: Very large, iridescent black plumage with a long, wide keel-shaped tail; male has yellow eyes; female is brown and much smaller. Bronzed Cowbird: Red eyes, conical beak; male: all black with a bronze iridescent sheen; female: gray-brown plumage without the sheen. Brown-headed Cowbird: Dark eyes, short, conical beak; male: brown head, black body, wings, and tail; female: grayish-brown plumage that is darker on upperparts, underparts faintly streaked, throat pale.
Habitat
All are known to occur in open to semi-open habitat including farms, fields, river groves, thickets, and city parks.
Feeding
• Diet: The grackle’s varied diet includes plant matter, insects, reptiles, small fish, aquatic invertebrates, and eggs and nestlings of other birds; the two species of cowbirds feed mostly on seeds and insects.
• Behavior: These 3 species forage mainly by walking on the ground; the grackle also forages in trees and shrubs, especially when looking for eggs or nestlings. These birds generally feed in flocks.
Life History
The Great-tailed Grackle nests in colonies; both males and females may have more than one mate. The nest site varies but is usually in dense vegetation near water. The bulky, open, cup-shaped nest, which may be a few feet to over 20 (7 m) above the ground, is made of twigs, weeds, grass, rushes, and other available material. Bluish eggs (3-5) with brown scrawls hatch in 13 to 14 days. The young, which are fed only by the female, leave the nest about 3 weeks after hatching.
Both cowbird species are brood parasites, laying their eggs in other birds’ nests where they are incubated by the host parents. In some areas this parasitic behavior has greatly diminished song bird numbers.
The Bronzed Cowbird may lay 1 pale blue-green egg per day for several weeks; the female may pierce the eggs of its host while depositing her eggs. Nestlings are fed by the host and leave the nest 10 to 12 days after hatching. Common host birds include orioles, towhees, and thrashers. Although now rather common, the Bronzed Cowbird was not recorded in Arizona until 1909.
The Brown-headed Cowbird may lay one whitish spotted egg per day for several weeks until 40 or more eggs have been laid; the female often removes the eggs of its host before depositing her own. Nestlings are fed by the host and leave the nest 10 to 11 days after hatching. Common host birds include finches, warblers, and vireos. The Brown-headed Cowbird is known to have parasitized over 200 species of birds with well over 100 species known to have successfully raised cowbird young.
Feathers
The typical feather with a shaft and vane is called a contour feather. These feathers occur on the body, the wing, and the tail. They form the outer covering of the bird providing protection from sun, wind, rain, and abrasion. The contour feathers on the wing and tail are primarily involved in promoting flight. Down feathers are frequently found underneath the body contour feathers. These feathers have a minute shaft; barbules lack hooks and flanges. The result is a very “downy”feather. Their position under the protective body contour feathers provides an air trap that facilitates heat conservation. There are several other types of feathers that have specialized functions. Semiplumes, filoplumes, bristles, and powder down are examples.
Orioles
Representative Sonoran Desert species:
Hooded Oriole (Icterus cucullatus)
Bullock’s Oriole (Icterus bullockii)
Order: Passeriformes
Family: Icteridae
Spanish names: calandria (Oriole); calandria zapotera, naranjero,
bolsero (Hooded Oriole)
Distinguishing Features
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Hooded Oriole: Sharply-pointed bill, two white wing bars. Male: black back, wings and tail and a large black bib from face to upper chest; orange head, belly, rump; white wing bars. Female: olive green above, olive-yellow below. The immature male looks like the female, but has a small black bib.
Bullock’s Oriole: Sharply-pointed bill. Male: black cap, nape, eyeline, back, wings, and tail; narrow black bib; orange face, underparts and and rump; white patch on wings. Female: olive-gray upperparts, dull yellow throat and chest, whitish-gray belly.
Habitat
Hooded Oriole: Open woods, tree plantations, palms, city parks, and suburbs; favors groups of palms for nesting, even when these trees are in cities.
Bullock’s Oriole: Common and widespread in the west, this species inhabits woodland, isolated groves of trees, streamside growth (especially cottonwood), farms, ranches, city parks, and suburbs.
Feeding
• Diet: Both species feed primarily on insects and take lesser quantities of fruit and nectar.
• Behavior: Both species forage by searching for insects in trees and shrubs; flowers are visited for nectar; feeders with sugar-water also attract orioles. The Hooded Oriole is a slow and deliberate forager, which makes it a rather easy bird to observe in the field.
Life History
The nest of orioles is often parasitized by cowbirds; the aggressive young cowbird usually receives the most food which eventually starves the oriole nestlings.
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The Hooded Oriole lays 3 to 5 bluish or grayish-white, spotted eggs in a long, hanging, woven pouch that it enters from the top. The nest usually hangs in a palm, large yucca or a eucalyptus tree. Incubation is by the female and takes 12 to 14 days; both parents feed the nestlings.
The Bullock’s Oriole lays 3 to 6 bluish-white to pale gray, spotted eggs in a hanging pouch firmly attached to a tree branch. Incubation is by the female and takes 12 to 14 days; both parents feed the nestlings.Young leave the nest about 12 to 14 days after hatching.
Finches
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The bird world includes few vegetarians. Even most birds adapted for eating seeds—such as the sparrows and grosbeaks, with their thick seed-crushing bills—switch over mostly to insects in summer, and feed their young on a high-protein insect diet. However, the true finches stick with plant material all year long, feeding on seeds, buds, and berries, with only the occasional insect. Their young are fed the same fare, although at first they receive their seeds in a softened, partly digested, form.
Wild seed crops vary from season to season, so many finches are somewhat nomadic, their flocks moving around in response to changing food supplies. Lesser Goldfinches live year-round in the Sonoran Desert, but sometimes they are locally abundant. Where the flower heads of fiddlenecks (Amsinckia spp.) are going to seed, for example, Lesser Goldfinches may descend in flocks, bringing flashes of color and a constant musical twittering. At other times, they may be seen only as isolated couples. A pair may raise young any time from early spring to late fall, perhaps when food supplies seem favorable.
Less nomadic is the House Finch, which has adopted a winning strategy: it is adapted to living around humans. House Finches in our region may have learned to live around Native American villages centuries ago, and they found an equally good niche around farms, suburbs, and big cities. Accidentally introduced into the eastern United States about 1940, House Finches are now found from coast to coast, but in many areas they are strictly urban dwellers. Not so in the Southwest. Here they do well in the cities, but they also continue to thrive in desert canyons, where these attractive and musical little finches had lived all along.
—Kenn KaufmanRepresentative Sonoran Desert species:
House Finch (Carpodacus mexicanus)
Lesser Goldfinch (Carduelis psaltria)
Order: Passeriformes
Family: Fringillidae (Finches)
Spanish names: gorrión común, gorrión doméstico (finch)
Distinguishing features
House Finch male: brownish with shiny pink or orange-pink crown, rump, and breast; heavy streaking on the sides and back. Female: all brown, heavily streaked underparts. Lesser Goldfinch male: black cap, black or green upperparts, bright yellow underparts, white wing bars on black wings. Female: greenish upperparts, yellow underparts, black wings and tail, white wing bars.
Habitat
The House Finch inhabits ranches, towns, canyons and agricultural areas; found in deserts only where water is available; often seen at bird feeders, nesting on porch lights, or under eaves.
The Lesser Goldfinch is found in open or semi-open areas where there are trees or brushy vegetation; found near water in more arid regions; also visits suburban gardens.
Feeding
• Diet: Almost entirely seeds, buds, and other vegetable matter; feeds on insects to a lesser extent.
• Behavior: Both species forage in flocks, except during nesting season. The House Finch forages on the ground and in trees or shrubs; it will come to bird feeders offering seeds or sugar water. The Lesser Goldfinch is an active and acrobatic forager in trees, shrubs, and weeds.
Life History
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House Finch: The female builds a compact cup-shaped nest of grasses, hair, cotton, and other plant fibers; the nest is placed in a cactus, low tree, or shrub, or on a building ledge. The female incubates the 2 to 6 black and lavender dotted pale blue eggs for about 2 weeks. The male feeds the female during courtship and incubation. Both parents feed nestlings; the young fledge in 12 to 15 days. This bird may nest several times during one season.
Lesser Goldfinch: During courtship the male keeps close to the female, often perching near her and singing. The female builds an open cup-shaped nest of grasses, hair, feathers, other plant matter; the nest is typically placed in trees from 15 to 40 feet (5-13 m) above the ground. The female incubates the 3 to 6 pale bluish-white unmarked eggs for about 2 weeks. The male feeds the female during during incubation. Both parents feed nestlings; the young fledge in 11 to 13 days. In the Sonoran Desert region, breeding season is quite long, extending from February or March to September or October.
