480 NATURAL HISTORY OF BIRDS. 



In speaking of the species of the creeper-like, point-tailed Synallaxinse, of Lower 

 Uruguay, Mr. W. B. Barrows observes as follows : " These birds are very abundant 

 at Concepcion, their nests being one of the most noticeable features of the landscape. 

 There are places within two miles of the centre of the town where I have stood and 

 counted, from one point within a radius of twenty rods, over two hundred of these 

 curious nests, varying in size from that of a small pumpkin to more than the volume 

 of a barrel. Often a single tree will contain half a dozen nests or more, and not 

 unfrequently the nests of several different species are seen crowding each other out of 

 shape on the same bush or tree. Most of the smaller species are so similar in color 

 and motion that they cannot possibly be distinguished from each other at a distance 

 of twenty feet. And it can easily be imagined how difficult it is to collect eggs and 

 be sure of their identification. The eggs of most species are as much alike as the 

 parrots themselves ; often more so, for the eggs are always either white or pale blue." 



One of the most interesting structures is that of the thorn-bird (Anumbius annumbi), 

 described by the same author as follows : " The bird is not larger than our wood- 

 thrush (Turdus mustelinus), but its nest is sometimes four feet in length, with an 

 average diameter of two feet. Probably no nest as first completed would show these 

 dimensions ; but as the same nest is used for several seasons in succession, its size 

 increases, until it may even exceed the above measurements. The bird builds its nest 

 of twigs and thorns, placing it either on a tree or bush, sometimes low enough to be 

 reached by the hand, sometimes at a height of twenty or thirty feet. The first new 

 nest I ever examined was built in an ombu tree at Buenos Aires, and measured about 

 two and one half feet in height by fifteen inches in diameter. The larger diameter 

 was vertical, and the opening at the top gave access to a passage-way, barely large 

 enough to admit the hand, and twisting regularly in a spiral to near the bottom, 

 where it enlarged somewhat to form the nest cavity. The spiral passage-way made 

 rather more than two complete turns between orifice and nest, and in so doing passed 

 between two branches of the tree so close together as barely to allow the passage of 

 the bird. I have several times seen nests in which these passage-ways were made to 

 pass completely around the (small) main stems of the trees on which they were built. 

 In other nests, the passage-way, though never straight, was by no means a spiral." 



The nest of the oven-birds (Furnarius) is quite a different affair, being, as the 

 name of the bird indicates, an oven-shaped structure built of clay. Once more we 

 resort to Mr. Barrows' excellent account of the nesting habits of these birds, from 

 which we quote the following, relating to the nesting of the ' hornero,' as the red oven- 

 bird (Furnarius rufus) is called, in lower Uruguay : " The nest is built of such mud 

 as can be found near at hand, and if the mud contain grass-roots or similar fibres, so 

 much the better, but I do not think the birds worry themselves much about the qual- 

 ity of the materials. Although the eggs may not be laid until September or October, 

 the birds often begin work on the nest as early as the middle of June, thus occupying 

 three months or more in its completion. In fact I doubt if there is any month in the 

 year when one cannot find oven-birds at work on their nests. If the weather is dry 

 they suspend work for a week or two until a shower refills the muddy pool from 

 which they draw their building material, when they go on leisurely as before. This is 

 the case only in winter, and when there is nothing to cause haste. In spring and 

 summer the case is entirely otherwise; a nest may then be begun and finished within 

 a week But a winter-built house is usually much the best, and not a few such with- 

 stand the rain and heat for a year or more, if not sooner pulled down by boys, iguanas, 



