Verdin

Published by the Smithsonian Institution between the 1920s and the 1950s, the Bent life history series of monographs provide an often colorful description of the birds of North America. Arthur Cleveland Bent was the lead author for the series. The Bent series is a great resource and often includes quotes from early American Ornithologists, including Audubon, Townsend, Wilson, Sutton and many others.

Bent Life History for the Verdin – the common name and sub-species reflect the nomenclature in use at the time the description was written.

This little olive-gray bird, with a yellow head and chestnut shoulders, is one of the characteristic birds of the southwestern desert regions. I made its acquaintance in a dry wash in southeastern Arizona, where the hard stony soil supported a scanty growth of low mesquites, hackberries, hawthorns, catclaws, and other little thorny shrubs, with a few scattering chollas. Here it was living in company with cactus wrens, crissal thrashers, and Palmer’s thrashers. Elsewhere in that region we found it on the mesquite plains, on the greasewood and cholla flats, and on the low hillsides dotted with picturesque giant cactus. It and the other desert birds seem to make a living in the harsh and cruel desert, far from any water, where the soil is baked hard and dry and every living plant is armed with forbidding thorns; even the “horned toad,” which is really a lizard, carries a crown of thorns on its head and lesser spikes on its body, to protect it. But the verdin is equal to the occasion and builds its own armored castles, protected by a mass of thorny twigs, in which to rear its young, and to which it can retire at night.

Dr. Joseph Grinnell (1914) says of the haunts of the verditi in the lower valley of the Colorado River: “The only essential condition for the presenc,e of this species appeared to he stiff-twigged thorny bushes or trees of some sort. This requisite was met with in a variety of situations, as in the screwbeans of the first bottom, mesquites of the second bottom, and catclaw, ironwood, palo verde and daleas of the desert washes. * ** While the birds were often seen in willows, arrowweed, and even low shrubs of Atriplex and sandburr, these were always within a limited radius of nests. As far as observation ~vent, these birds do not need to visit water; some were met with as much as three miles away from the river up desert washes”

Near Brownsville, Tex.. we found the verdin only in the high, dry, thorny chaparral, and not in the dense and heavy timber along the resacas. George Finlay Simmons (1925) says that, in the Austin region, “bushy mesquite valleys” are preferred to open deserts.

Nesting: The remarkable nests of the verdin are much in evidence throughout its habitat, especially large for so tiny a bird, wonderfully well made, and surprisingly conspicuous, for they are usually placed at or near the end of a low limb, without a shred of leafage to hide them. The number of nests that one sees would seem to indicate that the bird is more ahundant than it really is. But it is well known that the verdin builds roosting nests, or winter nests, as well as breeding nests. They are most industrious little nest builders. Furthermore, the nests are so firmly made that old nests probably persist for more than one year, perhaps several years. Most of the nests that we saw in Arizona were in mesquites, hackberries, or catclaws, but others have found them in palo verdes, stunted live oaks, Zizyphus bushes, chollas, and a variety of other thorny trees and shrubs.

Of the numerous descriptions of the marvelous nest of the verdin that have been published, I have selected Herbert Brandt’s (1940) as best worth quoting:

This structure is a globular or oval interlacement of thorned twigs that may measure up to eight inches in outside diameter, although usually its axis is shorter in one direction than the other. The thorny sticks are so placed that on the bristling exterior their free ends project upward, quill-like, and protect the nest. Each twiglet measures from two to five inches, and the free end may protrude an inch or more, in orderly fashion, so at first glance the twig ends give the appearance of a strange little hedgehog sitting in a convenient crotch with quills ever ready.

The number of twigs employed in this abode depends largely on its size and varies from a few hundred to more than two thousand; in fact I have a nest. collected in Arizona, that by careful estimate has over two thousand twigs! Thus the amount of labor required to interweave and lodge each individual freshly broken twiglet is indeed prodigious and is perhaps unequalled in the nest-building of our small birds.

One of the most interesting features of the Verdin’s dwelling is its strength; so strongly is it huilt that it is really difficult to tear one apart, and even then it is necessary to wear heavy gloves because the multitude of thorns will effectively repel one’s bare hands. The nest is so woven around the tough branching limbs that to remove it intact is impossible without cutting off the support; in consequence the winds of the sandstorms cannot harm it or its feathered tenants. In fact, this is. the most perfectly defended and anchored fortress that any desert bird has devised, and the reason so many are seen is because they endure year after year in various disrepair despite the angry elements that sweep across the sandy plains, often for months on end.

These nests are found as low as two feet from the ground and up to a height of nearly twenty feet. yet they are usually placed in the lower half of the tree in which they are built, or in the upper part of bushes, but always well out toward the end of a branch. Here the structure is woven about a pronged fork, with its entrance almost invariably opening outward and downward. The stick quills usually bristle backward away from this threshold, pointing along the limb, and act as a barbed repellent to any crawling invader trying to reach it from behind. It is through this small hidden orifice, itself well thorned, that the bird enters, and when it does it must pass over a raised threshold that is built up so high that one can scarcely touch the contents of the interior without pressing down the elevated doorstep. The whole fortified little stronghold seems designed to keep safe its semi-concealed entrance.

After suggesting that the male probably builds several nests, among which his mate may select her choice, he continues:

Once she has decided on her apartment she proceeds to line it snugly. The first step is to cover the many rough, protruding rafter ends with a padding of leaves and grass fibers, and finally to line cozily the whole cavity with an abundance of feathers, large and small. This room, before the feather finish, measures up to four inches across and between two and three inches high, but after the lining is placed, loose feathers more or less fill the entire chamber. Then the walls are smooth and silky to the touch, and so carefully padded that seldom does a thorn jab through. In one instance I found the nest of a Verdin only four feet below that of a Pallid Horned Owl containing two large young. The Verdin’s tiny stick-built Suite was crammed full of fluffy reddish feathers seized from the tiger of the air that dwelt in the master apartment above.

Mr. Simmons (1925) describes the nest much as above and then adds that “woolly and sticky fibers and weeds bind the nest together, and the whole structure is well interwoven with cobwebs and spider webbing, with some plant down and thistle down used to block up crevices”; the inside is “first lined with spider webs, forming a very thin coat which covers the cup-bottom; then lined with a coat of small grass leaves and bits of dead leaves; then an inner coat of plant down, thistle down, spider webbing, bits of silk-like cocoons, and a number of tiny soft bird feathers, on which the eggs rest”

Mary Beal (1931), of Barstow, Calif., has seen a verdin’s nest in an almond tree and in a tamarisk. The pair that built the nest in the almond tree had first built their usual nest in a mesquite in her back yard, but a pair of English sparrows took possession of it. The verdins started to build in a Chinese elm, but the sparrows tore the nest to pieces; and “every location the Verdin considered was made impossible by the annoying tactics of the sparrows. Finally, the harassed Verdin chose the branch of an almond tree in the midst of the adjoining orchard. The tree was blossoming when the nest was built, the lovely fragrant flowers almost concealing it. By the time the petals had fallen the leaves were out, keeping the nest securely hidden from casual sight. Here, in this unusual setting, the little family was reared in peace”

M. French Gilman (1902) says that, on the Colorado desert of southem California, “most frequently the nests are found in mesquite trees and the smoke tree or Dalea spinosa, Daley’s thorn tree. But any spiny shrub will answer, as I have found nests in the screw-hean, cholla cactus, desert willow, tree-sage, catsclaw, Eriodictyon, and last month I found one in a grapevine growing up in a cottonwood tree. The nests will average about five feet from the ground though I have found them as low as 2~/~ feet and as high as ten or twelve feet”

Dr. Walter P. Taylor has sent me the following notes on nestbuilding:

The male seemed to be much busier than his mate; his yellow head and brilliant red epaulettes were prominent. With his mouth full of nesting material he took a look at me. Deciding I was cluite safe he went to the nest, climbing into it from the bottom, and remaining for several moments, undoubtedly arranging his material. He reappeared, looked me over again, then resumed his search for nest material on the ground beneath a nearby catclaw. As he proceeded, he picked up many small twigs and dropped them again, being, apparently, very uncertain as to just what kind of a stick he wanted, and very wasteful of his energy. One twig in particular he handled for some time, then dropped it, apparently unintentionally, but seemed immediately to forget all about it, and went right on looking.

One that he watched on October 31, 1919, was apparently gathering material to line a winter nest: “One seen this morning picking cotton from a wad I had affixed to a hackberry to mark the site of a mouse trap. It pecked down on the cottony wad several times and until its bill held as much as possible. Then it flew to another branch of the hackberry and rearranged the cotton in its bill. Then it flew by ‘flirty’ flights to a mesquite not far away, then made off for a long flight over the mesa to a point where I could not follow it. This bird, or another, was back in a few moments for another load of cotton”

Mr. Sennett (1878) had several experiences indicating that the verdin will desert its nest, if the eggs are handled before the set is completed.

James B. Dixon tells me that the verdin apparently raises two broods in favorable seasons on the Colorado desert, as he has found nests with eggs in late February and early March and then found them with fresh eggs again during the first week in May of the same year.

Eggs: The cozy nest of the verdin may contain anywhere from three to six eggs, but normally four; sets of five are not especially rare; Mr. Gilman (1902) states that sets of four and five are “about evenly divided as to frequency,” though most others agree that four is by far the commonest number. The delicate little eggs are dainty and beautiful. The ground color is light bluish green, greenish blue, or bluish or greenish white. This is usually rather sparingly and irregularly marked with fine dots, small spots, or rarely with very small blotches of reddish brown. Usually the markings are much scattered, but sometimes they are concentrated in a ring around the large end. The measurements of 50 eggs average 15.3 by 11.0 millimeters; the eggs showing the four extremes measure 16.3 by 11.2, 15.2 by 12.2, 14.0 by 11.2, and 14.7 by 10.2 millimeters.

Young: \Vhether both sexes incubate does not seem to be definitely known, but, as the male is known to build his own roosting nest, perhaps incubation is performed entirely by the female. The incubation period of most of the Paridae is about 14 days, but Mrs. Wheelock (1904) says:

In ten days after the last bluish white egg was laid, there were three infinitesimal bits of naked bird life, huddled tightly together in the middle of the feather-lined hollow. A slit carefully cut at this time and fastened shut after each observation enabled me to keep an exact record of the development of the brood. Although I could not watch the mother feeding the young, I am positive it was done by regurgitation, for she would eat as unconcernedly as if merely occupied with her own dinner, and fly at once with apparently empty mouth into the nest, emerging shortly to repeat the performance. During the first five days the male was not seen to go into the nest, but sang right merrily neat by. After that time the young began to make themselves heard in hungry cries, and he began to carry food to them, which we could see in his bill. This food consisted almost exclusively of small green worms, and eggs and larvae of insects. The young Verdins remained in the nest quite three weeks, and long after their debut they returned to the nursery every night to sleep.

The young are fed by their parents for some time after they leave the nest and are well able to fly. They sit around in the bushes waiting to be fed, and uttering notes much like those of the adults but shorter and weaker, while their parents are foraging for food.

Plumages: I have seen no very young verdins, but apparently they are hatched naked, and they probably acquire the juvenal contour plumage before they leave the nest. Young birds in juvenal plumage have no yellow on the head and no chestnut on the lesser wing coverts. The entire upper parts, crown, back, rump, and lesser wing coverts are uniform grayish brown, “hair brown”; the under parts are very pale brownish gray, nearly white posteriorly; the wings, ïexcept the lesser coverts, and the tail are as in the adult. The postnuptial molt of the adult begins before the end of July and may last well through September; I have seen molting adults as early as July 28 and as late as September 29. Probably the postjuvenal molt comes at about the same time.

Food: Very little has been published on the food of the verdin, which seems to consist of insects and their larvae and eggs, and of wild fruits and berries. Dr. Taylor tells me that he has seen one eating the berries of the hackberry tree. Mrs Bailey (1928) writes: “These little desert birds would seem almost independent of water, nests having been found at least ten miles from any known water. The question is whether by means of their insect food and berries they are made largely independent of other liquid”

Behavior: In its movements and all its activities the verdin shows its relationship to the chickadees, as it flits about actively in the bushes searching for its food, clinging tenaciously to branches swayed by the wind, or hanging head downward from the tips of twigs, hunting every little crevice and the under sides of the foliage. During the nesting season it is shy and retiring; perhaps we should say sly, rather than shy, for it slips away unobserved from its nest and keeps out of sight in the nearest thicket; it is difficult to surprise one on its nest, and one is seldom seen near the nest unless it has young, when the little bird becomes quite bold, flitting about in the vicinity, chippering and scolding. But in winter its behavior is somewhat different, according to Mr. Brandt (1940), who says that “like the chickadee, the Verdin becomes more sociable, responding readily to my summons, and is one of the first birds to approach, showing little fear as it ‘cheeps’ in a thin voice and moves quickly about in anxious inquisitiveness”

Voice: The verdin has a remarkable voice for so small a bird, one that would do credit to an oriole or a thrush. Dr. Taylor says in his notes: “The song of the verdin I put down as tswee, tswee, tswee, tsweet! All the calls are whistled. Another call is tsee, tsoo, tso or! and isee, tsoo, tsooy!” He writes the common short call note as tsit, tsit, tsit, tsit; the notes are run together more or less and are repeated very rapidly.

Mary Beal (1931) says: “The Verdin’s song of three clear notes all on one key has rather a plaintive, resonant quality. One summer when I lay ill for all the weeks of June in a sleeping porch in the midst of many trees, those liquid bird-notes came to me across the orchard at intervals throughout the day. The vital quality compelled attention and puzzled me all that season, for I did not place the singer until the next spring when I saw a tiny Verdin in the act of sending forth those rich, full notes. The depth and carrying power of the tones are amazing in such a small bird: so different from its quick, sharp call-note”

Mrs. Wheelock (1904) writes: “The usual note of the adult Verdins is a chickadee-like ‘tsee-tu-tu’ uttered while hunting, chickadee fashion, among the terminal buds and under the leaves for their insect food, and this the nestlirigs mimic in two syllables as soon as they leave the nest,: tsee-tee, tsee-tee. It is a cry of hunger, and never fails to bring the parent with food”

Enemies: Dr. Herbert Friedmann (1929) records the verdin as “a poorly known victim of the Dwarf Cowbird.” He found a cowbird’s egg in one nest, near Brownsville, Tex., and Roy W. Quillen wrote to him that he has found “eggs of the Cowbird in a few nests of the Verdin.” In all cases the entrances to the nests were much enlarged. and perhaps deserted.

Field marks: The verdin is a tiny bird, about the size of a bushtit and much like it in general appearance and behavior, but it has a shorter tail and other distinctive markings: it is brownish gray above and paler below: in the male the head is largely qmte bright yellow and in the female somewhat duller yellow; the lesser coverts on the bend of the wing are bright, reddish chestnut, but these do riot show conspicuously unless the wings are partially open. Young birds in their first plumage in summer have no yellow on the head and no chestnut on the wings. The verdin’ s voice is quite distinctive.

Winter: The verdin is a permanent resident in at least the warmer portions of our southwestern deserts; it does not have to migrate, for it finds sufficient insect food in one form or another and lives well on various wild fruits and berries. But it builds most interesting winter homes for its protection and warmth. Mrs. Bailey (1928) says that in southern Arizona, out of fifteen Verdin nests that I found in one small tract, ten showed signs of winter occupation and nine ~vere found to contain roosting birds, the small occupants being flushed at intervals from 4.28 P.M. until after sunset, at various dates from December 9, 1920, to March 13, 1921. Two of the little birds seen going to their nests went half an hour or more before sunset, when it was light enough to be seen by Sharp-shinned Hawks and any other too observant neighbor”

She noticed that these nests were usually under thick thorny trees or bushes, which gave the bird some additional protection as it went to its nest.

Mr. Gilman (1902) writes: “Last December I found two female winter nests and later saw several of both sexes. One of them in a mesquite tree was ten or twelve feet from the ground and measured more than eight inches long by seven wide and seven deep. Lining was about one and one-quarter inches thick and composed of feathers: quail, chicken and others. * * * The nests of male and female differ a little, the former being less elaborate, smaller, with not so much lining in it. The female winter nest differs but little from the breeding nest and I am inclined to believe in some cases is used as such”

W. L. Dawson (1923) says that “two male lodges in the M. C. 0. are each only three inches in length over all, with openings at either end, and about two and a half inches of clear space inside: not room enough to turn around in, but just sufficient protection from the pounce of an Elf Owl. * * * Verdins are not gregarious, like Bush-tits; but also they are never solitary, for they roam the desert in pairs, or, in small family groups, or in loose association. It is here that the remarkable penetrative, or carrying power, of the sup note serves the Verdin in good stead, for it allows mated birds to hunt, say, a hundred yards apart, without actually losing each other”

DISTRIBUTION
Range: Southwestern United States and northern Mexico; not regularly migratory.

The range of the verdin extends north to southern California (Victorville, Barstow, and Death Valley) ; southern Nevada (Corn Creek and Bunkerville) ; southwestern Utah (St. George); southern New Mexico (San Antonio, Tularosa Flats, and Carlsbad); and southwestern Texas (Monahans, Castle Mountains, Kerrville, and Sequin) East to central Texas (Sequin, Corpus Christi, and Brownsville); and eastern Tarnaulipas (Matamoros). South to northern Tamaulipas (Matamoros); southern Coahuila (Saltillo and Saral) ; probably Durango (Durango); and southern Baja California (San Jose del Cabo and Cape San Lucas). West to Baja California (Cape San Lucas, Magdalena Bay, San Ignacia, and San Felipe); and California (San Diego, Palm Springs, and Victorville).

Three subspecies of the verdin are now recognized by the American Ornithologists’ Union (1944) committee on nomenclature. Modern research, for which the references are given in their nineteenth supplement to the Check-list, indicates that the Cape verdin (Auriparus flaviceps flavice Ps) should stand as the type race of the species, as Sundevall’s type apparently came from the southern half of Baja California.’ The eastern verdin (A. f. ornatus) occupies southern Texas, southern New Mexico, and southern Arizona; and Grinnell’s verdin (A. f. acaciarunt) ranges from southern Nevada and southwestern Utah to northern Baja California.

Egg dates: Arizona: 40 records, March 4 to June 18; 20 records, April 17 to May 18, indicating the height of the season.

California: 56 records, March 6 to June 8; 28 records, March 28 to April 11.

Mexico: 26 records, March 22 to June 25; 14 records, April 7 to May 8. Texas: 30 records. April 1 to June 5; 16 records, April 18 to May 6.

GRINNELL’S VERDIN
AURIPARUS FLAVICEPS ACACIARUM Grinnell
Dr. Joseph Grinnell (1931) made an exhaustive study of the nomenclature of this species and an extensive search for Sundevall’s type, to which the reader is referred for the somewhat confusing details and a history of the nomenclatorial changes. In the course of his study he concluded that the vercilins of southeastern California needed a new name, for which he proposed the subspeciflc name acaciarum. He describes this race as “similar to Auriparus flaviceps fiaviceps (Sundevall), but with yellow of fore parts somewhat less intense and extensive; body color averaging a trifle browner, especially on dorsum; tail and wing, more notably the former, averaging a little longer; bill apparently averaging smaller. Similar to A. f. ornatus (Lawrence), but paler and a little smaller”

The new Check-list will give the range of this form as from southern Nevada and southwestern Utah to northern Lower California.

CAPE VERDIN
AURIPARUS FLAVICEPS FLAVICEPS (Sundavall)
HABITS

Many years ago Baird (1864) called attention to the principal characters distinguishing the verdins of the southern part of Lower California from those of Arizona and Texas, but he did not propose a new name for the race. The most concise description is given by Ridgway (1904), who says that it is similar to the northern race “but decidedly smaller (except bill), with yellow of head averaging brighter, and the forehead more frequently (?) tinged with orange-rufous; young, howeven, distinctly different in coloration from that of” the northern race, “the upper parts being olive, strongly tinged with olive-green, and the under tail-coverts (sometimes most of under parts) tinged with oliveyellow”

According to the 1931 Check-list, the Cape verdin occupies the “Lower Austral Zone in the southern part of Lower California, south of about lat. 30~, and in southwestern Sonora.” William Brewster (1902) says that Frazar found it “abundant everywhere in the Cape Region except on the Sierra de Ia Laguna, where none were met with. It was breeding at La Paz in March, at Triunfo in April, and apparently at San Jose del Cabo in November, for on the third of that month Mr. Frazar found two nests about half completed on which the birds were busily at work.” These November birds were probably building winter nests.

Griffing Bancroft (1930) writes of its haunts in central Lower California:

This is the most widely distributed and, I believe, the most abundant of the local birds. It occurs in every association of the region under discussion, excepting only the littoral sand dunes. On the lava-strewn mesas, where vegetation is barely able to maintain a foot-hold and where animal life seems almost impossible, isolated pairs of these fascinating little workers are to be found regularly and in surprising numbers. In the irrigated river beds they seek open spots where here and there a stray mesquite or a bit of cholla has been permitted to remain. Brush-covered mountain slopes, plains dotted with cholla, card6n, and tree yucca, dry river beds supporting dense mesquite and palo verde, and caz~ons where the palo blanco grows are equally their home sites.

Nesting: The same observer writes: “Fifty percent of the nests are in cholla, forty percent in mesquite, and the other ten percent scattering. The latter include anything from elephant trees to matilija poppies.” He continues:

When nest building begins both bitds work industriously. They find an arrangement of cholla stems in which it is possible to construct a suitable circle about five inches in diameter. They build one of fine weed ïtwigs or of grass stems which often have leaves still attached. These inch-long bits are fastened to the cadtus with a layer of plant down, the bird standing within the rim and tucking in the material with a most business-like air. The next step carries the outside super-structure backward from the ring to supporting arms of cholla. The frame is of the same material as the original circle. The builders continue to work from the inside and soon the frame becomes a shell. That, in turn, is added to and padded until a thickness of perhaps half an inch is reached.

The result is a flexible nest. In marked contrast to those of Arizona and particularly the Vizcaino Desert and Sonora it is hardly ever protected on the outside with reinforcement in the shape of thorns or larger twigs. * * *

The opening to the hollow globe is completed last. It is left just large enough to permit the entrance and egress of the parents and it is so placed as to face away from the plant on which the nest is built. It is almost level with the bottom (only once did I observe a hole squarely in the center), and it is often somewhat concealed with an overhang of building material. The interior design permits of the low entrance being safely used. The tunnel runs upward. At the interior end the wall of the nest drops abruptly or even outwardly. So the eggs lie directly below the entrance. It is interesting to note that this is not true of the nests of any other race of verdin.

The nests are lined with feathers and are located in the trees much as are those of the Arizona verdict. In fact, J. Stuart Rowley, who saw many nests in the same general region, tells me that the nesting habits are the same as in Arizona.

There are five nests of the Cape verdin in the Thayer collection in Cambridge. One of these, taken at Comondu on April 24, was 4 feet up in a mesquite and is quite unique, unlike any verdin’s nest I have ever seen. It is made almost wholly of white woolly or cottony substances, reinforced with a few short pieces of fine twigs and weed stems, mixed with a few dry leaves and feathers; there are no long or thorny twigs even on the exterior, and the whole nest is conspicuously white.

The other four nests, collected at Purissima in May and June, are quite unlike the above and very different from any nests of the Arizona verdin in the almost complete absence of thorny or large twigs. They are all very much alike and are, or rather were, more or less globular structures, made up of great compact masses of short fine twigs, weed and grass stems, flower clusters, fine straws, insect cocoons, and various kinds of plant material; they contain considerable plant down in the lining, but very little of the white woolly material and only a few feathers; only one contains a few small thorny twigs on the outside. There is nothing in any of these nests that suggests the bristling, thorny fortresses of the Arizona birds.

Eggs: Mr. Rowley tells me that his sets of the Cape verdin consist of three eggs, except for one set of five, taken April 27, 1933, near San Ignacio. Mr. Bancroft (1930) writes:

The number laid is definitely not more than three: I have seen but one set of four out of a hundred examined. Clutches of three outnumber two in a ratio of approximately four to three. Incubated singles comprise about ten per cent of the total.

Eggs of the Cape Verdin run through a wide range of sizes, shapes and colors. Many are half again as large as the average and many are fifty per cent smaller. There is the elongated type, one end almost a hemisphere and the other a cone-shaped point. On the other hand it is not rare to find them as perfectly elliptical as die typical humming bird egg. The ground color is green, the markings gray: facts established for us by an oculist with the proper instruments. The shade of green varies until almost blue is reached.

The great variation in size, as indicated above, is not shown in the series of measurements I have collected, and the 15 eggs of this race I have examined are practically indistinguishable from those of the Arizona verdin. The measurements of 40 eggs average 15.3 by 11.2 millimeters; the eggs showing the four extremes measure 16.7 by 11.0, 15.2 by 12.2, 14.2 by 11.1, and 14.7 by 10.2 millimeters.

In all other respects, plumage changes, food, general behavior, and voice, the Cape verdin does not seem to differ from the Arizona bird.