The nest, being so secure and comfortable an abode, is greatly coveted by several other species of birds to breed in; but on this subject I have already spoken in the account of the genus _Molothrus_. When deprived of their nest, the birds immediately set to work to make a new one; but often enough, without being ejected from the first they build a second nest, sometimes demolishing the first work to use the materials. I watched one pair make three nests before laying; another pair made two nests, and after the second was completed they returned to the first and there elected to remain. Two or three nests are sometimes seen on one tree, and Azara says he has seen as many as six. Mr. Barrows observed the bird at Concepcion, where it is very common, and writes that in that district the nest is sometimes four feet long with an average diameter of two feet, and that the same nest in some cases is used for several seasons successively; also that several nests are sometimes joined together and all occupied at the same time. 207. LIMNORNIS CURVIROSTRIS, Gould. (CURVED-BILL RUSH-BIRD.) +Limnornis curvirostris+, _Scl. et Salv. Nomencl._ p. 64; _Durnford, Ibis_, 1877, p. 182 (Buenos Ayres). _Description._--Above rufous-brown, brighter on the rump; lores and superciliaries white; wings and tail chestnut-brown; beneath white; flanks and under tail-coverts pale brown; under wing-coverts white; bill and feet horn-colour: whole length 7·0 inches, wing 3·0, tail 2·0. _Female_ similar. _Hab._ Argentina and Uruguay. This species is found everywhere in marshy places in the eastern part of the Argentine Republic, and is also common in Uruguay, where Darwin discovered it. It inhabits dense reed-beds which grow in the water, and is not found in any other situation. It pairs for life, has a very feeble flight, and flies with great reluctance, but lives always in close concealment in one spot. It is, however, very inquisitive, and when approached the two birds creep up to the summit of the rushes and utter peculiar loud, rattling, and jarring notes, as if angrily protesting against the intrusion. The Rush-bird has a stout body and short graduated tail, strong claws, and a slender curved beak three-fourths of an inch long. The upper plumage is brown, the tail rufous, the under surface and a mark over the eye white. 208. PHACELLODOMUS FRONTALIS (Licht.). (RED-FRONTED THORN-BIRD.) +Phacellodomus frontalis+, _Burm. La-Plata Reise_, ii. p. 467 (Tucuman); _Scl. et Salv. Nomencl._ p. 65; _Salvin, Ibis_, 1880, p. 359 (Salta); _White, P. Z. S._ 1882, p. 612 (Buenos Ayres). +Phacellodomus sincipitalis+, _White, P. Z. S._ 1883, p. 433. _Description._--Above nearly uniform olive-brown, crown blackish brown, superciliaries white; beneath dirty brownish white; under wing-coverts pale cinnamon; bill and feet horn-colour: whole length 6·8 inches, wing 2·6, tail 2·6. _Female_ similar.