National Geographic : 1932 Jul
HUMMING BIRDS, SWIFTS, AND GOATSUCKERS CALLIOPE HUMMING BIRD (Stellula calliope) This species is the smallest of the humming birds of the United States, and is thus the tiniest of the birds that occur in this region. In north western Wyoming I found them in June in little valleys, often in swampy sections, where they rested on dead twigs in the tops of alders and other shrubs. Each male had his selected perch and objected vigorously to the encroachment of others on this territory, pursuing interlopers with rapid flight and squeaky call notes. Calliope hummers feed about flowers with other species of their family, and in spite of their tiny size are as pugnacious and aggressive as their larger relatives. The mating display flight of the male of this species is less spectacular than that of some of its relatives, the bird swinging in a semicircular path past his mate on the downward sweep, mak ing a loud metallic sound that may be heard for some distance. The nest ordinarily is placed in pine trees on or beside cones, and is so covered externally with bits of bark and small shreds of cone that it closely resembles a dead cone, the mimicry being so exact that nests are discovered usually by seeing the parent fly about them. The female has the throat spotted lightly with dusky and the sides washed with brown, other wise closely resembling the male. The Calliope humming bird nests from north ern British Columbia, southwestern Alberta and Montana, south through the higher mountains to New Mexico and northwestern Lower Cali fornia. It is found in winter in Mexico south to Guerrero and Mexico City. RUFOUS HUMMING BIRD (Selasphorus rufus) This is one of the most spectacular of our humming birds because of the brilliant color of the male and from the abundance of the species in its range. At times these birds fairly swarm, where thistles, agaves, and other flowers are abundant. Aggressive to a degree and filled with vibrant, nervous energy, these tiny mites seem never to rest, their feeding grounds being in constant turmoil, as the birds dash about with chattering calls in an endeavor to drive rivals away from favored flowers or perches. As they turn, the males glow in the sun like coals of fire, and in following their brilliant forms one en tirely overlooks the duller-colored females. The male dazzles his mate in a courtship flight in which he swings down from high in the air to pause fleetingly an inch away, and then rises swiftly to repeat the dashing performance. The nesting is generally similar to that of Anna's hummer (see page 74). Nests are placed in trees, shrubs, and bushes. The inside is com posed of cottony downs with the outside covered with fine moss and shreds of bark. The rufous hummer nests in Transition and Canadian zones from latitude 61° north, on the coast of Alaska, to east central British Columbia and southern Alberta south to Oregon and south western Montana. It is abundant in migration through the Rocky Mountain region and winters in southern Mexico. BROAD - TAILED HUMMING BIRD (Selasphorus platycercus platycercus) The broad-tailed hummer is one of the most abundant humming birds of the Rocky Moun tain region, where it has wide distribution. In flight the attenuated outer primaries produce a loud, metallic, rattling sound that can be heard for some distance, which brings the species con spicuously to the attention of those who visit its haunts. The broad-tail is preeminently a flower feeder, though it may visit the tree borings of sapsuckers to obtain sap and the insects attracted by this fluid. In its seasonal movements it is governed largely by the flowering of plants, following the changing season from the mountain foothills into the higher parks as summer advances and plants bloom at increasing altitudes. These hummers come regularly to gardens in towns located in their haunts. The male has a diving nuptial display resem bling that of some of the other hummers, exe cuted with much metallic rattling of the wings. The majority of nests are placed near the ground, and there is more variation in the ap pearance of the nest than customary in other species. Two broods, and possibly three, are reared each season, the eggs being two in num ber, as usual. The broad-tailed hummer nests from south ern Idaho, Montana, and southern Wyoming to eastern California, western Nebraska, and west ern Texas, south to the Valley of Mexico. It is found in winter in Mexico. ALLEN'S HUMMING BIRD (Selasphorus alleni) This species is generally similar to the closely allied rufous hummer and is often confused with that species, particularly when the plainly col ored female is concerned. The latter is dis tinguished from the related species by being slightly smaller, with the tail feathers narrower (not more than one-tenth of an inch wide, in stead of more than one-eighth inch, as in the rufous). This species, like the rufous hummer, is more than commonly aggressive among species noted for their pugnacity, and has even been known to drive large hawks to flight by its vigorous attacks. The male has a display flight somewhat like that of the broad-tail, in which he rises high in the air and then darts down with a loud metallic sound, produced by the rushing of air through the flight feathers. The species breeds princi pally in the coastal region of California, and after the nesting season scatters widely before the fall migration carries it southward. The nests are like those of Anna's hummer and may be in trees or in bushes. It is said that two broods are reared each season. Allen's hummer nests in Transition and Upper Austral zones from Humboldt County, Cali fornia (possibly extending into Oregon), south to Ventura County and the Santa Barbara Is lands. It is found in migration in eastern and southern California, Arizona, and Lower Cali fornia, and winters on the Santa Barbara Is lands and probably in northwestern Mexico.