National Geographic : 1932 Jul
HUMMING BIRDS, SWIFTS, AND GOATSUCKERS POORWILL (Phalaenoptilus nuttalli) Like the whippoorwill, the present species to most is a voice of the night, as the bird itself is seldom seen, its calls being the usual evidence of its presence. It is nocturnal in habit, resting by day in thick brush, in places where it is not easily disturbed. When flushed by chance, its dark form resembles that of a short-tailed whippoor will, as with erratic flight it seeks some secure hiding place. At times poorwills are found in growths of low forest, but they are more often encountered in regions where dense clumps of brush are scat tered over otherwise open ground, as is common in desert and semiarid localities, or in brush grown, rocky canyons, where the ground is rough and strewn with bowlders. They rest during the day on the ground, though after night, when feeding or calling, may seek higher perches on stones or posts or on low branches. On one occa sion I saw one by bright moonlight calling from a bush, where it perched crosswise on a small limb, like any ordinary bird, though ordinarily they rest lengthwise of branches, like others of their family. The call of this species resembles the syllables poor-will poor-will, poor-will-low, in imitation of which the bird is given its common name. Near at hand these calls are harsh, but with distance the first two assume a pleasant, somewhat mel ancholy cadence. The third, often omitted, is harsher and does not have the carrying power of the others. Occasionally, in the nesting season, one may be heard calling during the day. The poorwill feeds on insects-beetles, moths, and various species of the locust group being favorites. When feeding, the birds at times course along the ground, and at times rest in open places, rising in short flights to seize passing in sects in their capacious mouths, which are fringed with long bristles. They have been seen watch ing for insects attracted by electric lights, even seizing them as they fluttered against the globes. Hard portions of their food are ejected after digestion, in the form of pellets. The eggs are placed on a patch of gravel, on flat rock exposures, or in slight hollows scratched in the bare earth, without other semblance of a nest. They may be in the open or under shelter of brush. Two eggs constitute a set. They vary considerably in color, ranging from white to cream, unmarked or with delicate purplish spots. Both birds are said to assist in incubation. When disturbed about the nest, they tumble about and with widely opened mouths make a loud hiss ing sound terrifyingly like the hissing of a snake. Four geographic races of the poorwill are recognized at present within the limits of the United States. Nuttall's poorwill (Phalaenop tilus nuttalli nuttalli) is found from southeastern British Columbia and North Dakota to eastern Kansas, southern Arizona, and eastern California. It winters from California and Texas to central Mexico. The dusky poorwill (Phalacnoptilus nuttalli californicus) is found in California west of the Sierra Nevada, south to northwestern Lower California. The desert poorwill (Pha laenoptilus nuttalli hucyi) occurs in the valley of the Lower Colorado River. The San Ignacio poorwill (Phalaenoptilusnuttalli dickeyi) ranges in Lower California south of latitude 300. MERRILL'S PAURAQUE (Nyctidromus albicollis merrilli) The present form is a nocturnal species belong ing to a group of tropical distribution that barely crosses our border in the lower Rio Grande Val ley. It is found in wooded areas in the winter months, frequenting dense thickets in the low lands, and in the nesting season spreads to sec tions where the cover of shrubs and trees is more open. It rests during the day on the ground, or on low limbs, where it perches lengthwise of the branch, and is only flushed by chance, when it darts off with rapid, erratic flight to a more secure station. Though sensitive to light, it seems to fly easily and without difficulty, when fright ened during the day. The length of the tarsus, or lower part of the leg, and the strength of the toes in these birds is marked, compared with our other species. Seem ingly this would indicate greater ability and ease of movement on the ground, though this is not fully understood, as the habits of the bird are imperfectly known. The name pauraque, in early accounts of the bird erroneously written "parauque," is given in imitation of its call, according to the interpreta tion of these notes by the Mexicans who live near its haunts. The song is in three syllables and may be written pau ra kec, uttered in loud, harsh tones and repeated steadily, as is usual among its relatives. In addition, it has an explosive note that resembles the call of a turkey. The pauraque lives on insects that it captures in its large mouth on the wing, watching for its prey from a perch on the top of a bush, on a log, or from an open spot on the ground, and flying out quickly to seize those that pass. Not much is known of its food, except that it eats beetles of various kinds and moths. One naturalist re cords that he found the stomach of a pauraque filled with the beetles known as fireflies. The nest is placed on the ground, among scat tering bushes and cacti, at times at the borders of fields. The nesting season along the lower Rio Grande begins during the second week in April, reaches its height in May, and ends toward the close of June. It is possible that two broods may be reared each season. The two eggs are placed on the bare ground, usually near a clump of bushes, with no attempt whatever at nest-building. The eggs differ from those of other species of this family found in the United States in color, varying from cream to deep buff, spotted and blotched with varying shades of brown and lilac. Their bold markings are quite distinctive. Occasional eggs are nearly plain, with a few markings that are so fine that they pass unnoticed except on close examination, but this is unusual. The adult is said to offer little objection when the nest is approached, sit ting closely until it is forced to take wing, and then flying only a short distance before settling quietly on the ground. Merrill's pauraque ranges from the Gulf coast of southern Texas and the lower Rio Grande Valley south into Tamaulipas. In winter it is found in Mexico south to Vera Cruz and Puebla. It is a geographic representative of a wide-rang ing species that is distributed through tropical America to Brazil, dividing in this great area into five or more subspecies.