_Young_ (42,130, ♀, Mirador, Mexico; Dr. C. Sartorius). Black of adult replaced by dingy dark brown, this darkest in the hood; white and dusky regions gradually blended, the feathers of the breast being whitish, edged (longitudinally) with brown. No trace of the transverse bars, except on the tail, which is like that of the adult. HAB. Middle America north of Darien; southern border of United States from Florida to Lower California; Cuba. Localities: Guatemala (SCL. Ibis, I, 214); Cuba (CAB. Journ. II, lxxix; GUNDL. Rept. 1865, 221, resident); ? Trinidad (TAYLOR, Ibis, 1864, 79); Texas (DRESSER, Ibis, 1865, 329, breeds); Arizona (COUES); Costa Rica (LAWR. IX, 132); Yucatan (LAWR. 16, 207.) LIST OF SPECIMENS EXAMINED. National Museum, 16; Boston Society, 2; Philadelphia Academy, 4; Museum Comp. Zoöl., 1; R. Ridgway, 2. Total, 25. _Measurements._ +----+-----------+-----------+---------+---------+-----------+----------+ |Sex.| Wing. | Tail. | Culmen. | Tarsus. |Middle Toe.|Specimens.| +----+-----------+-----------+---------+---------+-----------+----------+ | ♂ |14.60–16.50| 9.00–10.00|1.20–1.48|3.20–3.60| 1.90–2.00| 6 | +----+-----------+-----------+---------+---------+-----------+----------+ | ♀ |14.75–16.00| 8.80–10.00|1.20–1.45|3.55–3.75| 2.00–2.10| 8 | +----+-----------+-----------+---------+---------+-----------+----------+ [Illustration: _Polyborus tharus_, var. _auduboni_.] HABITS. The Caracara Eagle, as this bird is called, though it seems to possess, to a large degree, the characteristics of a Vulture, and hardly any of the true aquiline nature, is found in all the extreme southern portions of the country, in Florida, Texas, Southern Arizona, and California. Audubon met with it abundantly in Florida in the winter of 1831. Mr. Boardman has seen it quite common at Enterprise, associating with the Vultures. Dr. Woodhouse, while encamped on the Rio Saltado, near San Antonio, in Texas, frequently saw the Caracaras, and always in company with the Vultures, which he says they greatly resemble in their habits, excepting that they were much more shy. He could, however, readily approach them when on horseback. Mr. Dresser also frequently encountered it in Texas in the vicinity of San Antonio, and speaks of it as abundant from the Rio Grande to the Guadaloupe, but never noticed any farther east. In Arizona, Dr. Coues says, it is not a rare bird in the southern and western portions of that Territory. Lieutenant Couch likewise describes them as exceedingly abundant from the Rio Grande to the Sierra Madre. He speaks of killing a male bird on the nest, which was in a low tree and composed of sticks. He adds that this bird destroys the Texas field-rats (_Sigmodon berlandieri_) in large numbers.