The Blue-throated Hummingbird is the largest hummer found north of the Mexican border (weight up to 10 g). Visually the male can be identified by its iridescent blue throat, while the eye-stripe and large white tail tips distinguish the female (see Pyle  and Williamson  for plumage details). The male’s high-pitched, monotonous “peeps” are also distinctive. One clue for separating females of the two large hummingbird species of the United States is nest height. Blue-throated Hummingbirds usually build below 3 m (10 ft) above the ground while the Magnificent Hummingbird’s (Eugenes fulgens) nest is usually much higher.
Found in the United States primarily in moist canyons in the border mountains of the southwest, this species adapts to the presence of humans in its favored habitat, visiting sugar-water feeders. There its aggressive behavior and large size place it at the top of the feeding hierarchy. Occasional individuals spend the winter at a feeding station. Females may build nests on buildings or even inside abandoned or infrequently used structures (Williamson 2000).
DISTRIBUTION. Most breeding evidence found by TBBA atlasers during the 1987-1992 field work was in the Guadalupe Mountains in latilong block 31104 (1 confirmed, 2 probable and 2 possible). In the vicinity of Big Bend National Park, 2 probable records were found in blocks 29104 and 30104. In the Edwards Plateau region a probable record was found in block 29099 and another probable comes from block 26099 in south Texas. These last two reports may be early fall migrants since Lockwood and Freeman (2004) report several sightings in late summer and early fall from locations east and south of the Trans-Pecos region. The habitats of these last two areas seem unsuitable for breeding, see Williamson (2000).
This species also breeds in southeast Arizona and southwest New Mexico and in the highlands of the Sierra Madres Occidental and Oriental and southwest Mexico to the Isthmus of Tehuantepec (Howell and Webb 1995, Williamson 2000).
SEASONAL OCCURRENCE. Oberholser (1974) reported Blue-throated Hummingbirds present in Texas from March 18 to October 24, Lockwood and Freeman (2004) report the species is on the breeding grounds from mid-April through September.
BREEDING HABITAT. Oberholser (1974) suggests the species probably breeds between 1500 and 2100 m (5000-7000 ft). In Arizona most breeding was found in cool, moist canyons with permanent or intermittent streams. The most common tree there is sycamore (Wise-Gervais 2005). Nests are generally low (0.6-3 m; 2-10 ft) above ground and often sheltered from above by a rock overhang or stream bank or in man-made structures. Nests are attached to tree branches, wires, nails chains or placed on rock surfaces at cave openings (Williamson 2000).
The nest, built by the male in up to 2 weeks for a new nest, is composed of plant fibers, feathers, insect cocoons, bound with spider silk. The outside diameter is 5-6 cm (2-2.4 in), inside diameter 3-4.5 cm (1.2-1.8 in) and cup depth 1.5-3.2 cm (0.6-1.2 in). Nests may be reused in the same or succeeding seasons or used as a platform for a new nest, one nest eventually reached a height of 25 cm (10 in); Williamson 2000).
The female lays 2 smooth dull white eggs (indistinguishable from those of Magnificent Hummingbird. She incubates them for 17-19 days. The young leave the nest 24-26 days (occasionally longer) after hatching. A female may raise as many as 3 broods in a season (Harrison 1979, Williamson 2000).
STATUS. Originally observed in the Chisos Mountains, later found in the Davis and Guadalupe mountains (Oberholser 1974, Lockwood and Freeman 2004). TBBA observations suggest Blue-throated Hummingbirds may be most common in the latter range.The future of this species in Texas is probably dependent on the condition of upper elevation habitats in the Trans-Pecos mountains.
Text by Robert C. Tweit (2006)
Harrison, H. H. 1979. A field guide to western birds’ nests. Houghton Mifflin, Boston, MA.
Howell, S. N. G. and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford University Press, New York.
Lockwood, M. W. and B. Freeman. 2004. The TOS handbook of Texas birds. Texas A&M University Press, College Station.
Oberholser, H. C. 1974. The bird life of Texas. University of Texas Press, Austin.
Pyle, P. 1997. Identification guide to North American birds, part 1. Slate Creek Press, Bolinas, CA.
Williamson, S. L. 2000. Blue-throated Hummingbird (Lampornis clemenciae). In The birds of North America, No. 531 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Wise-Gervais, C. 2005. Blue-throated Hummingbird (Lampornis clemenciae). In Arizona breeding bird atlas. pp. 250-251 (T. E. Corman and C. Wise-Gervais, eds.), University of New Mexico Press, Albuquerque.