Ant-birds 635 



and two feet or more long. These are disposed in such a way as to form a 

 structure three or four feet in length by two in breadth in the widest part, the 

 whole very much resembling a gigantic powder flask lying on its side among 

 the lower branches of a spreading tree. It is quite loosely built, and the nest 

 cavity is rather indefinite, being any portion of the floor of the nest the bird 

 selects for the reception of the eggs. These are usually three or four in num- 

 ber, pure white, and can usually be counted through the loose floor of the nest." 



THE ANT-BIRDS 



(Family Formicariidce) 



Closely related to the last family, but distinguished at once by the taxas- 

 pidean instead of endaspidean tarsi, is another great family of neotropical birds 

 known collectively as Ant-birds. They arc also of small size, being mostly 

 under ten inches in length and mainly confined in their distribution to the hot 

 tropical forests of Central America and northern South America, only very 

 few of the forty genera and nearly three hundred and fifty species reaching as 

 far south as northern Argentina and Uruguay. Many of them are ground- or 

 bush-haunting birds, frequenting the dense tangle of underbrush, through which 

 they run with great facility, and into the mazes of which they plunge on the 

 slightest cause for alarm, while others are found in low or medium-sized trees. 

 The wings are short and rounded, as they enjoy but limited powers of flight, 

 while the tail is of varying length though often short. The tarsi and toes arc 

 long and slender, the outer toe being united to the middle one at base, and the 

 claws are of moderate size, while the feathering of the rump is fine and slender, 

 and the interscapular region in the male is, in a majority of cases, marked with 

 a concealed patch of white. The color of the plumage varies considerably, but 

 inclines as a rule to dark brown or black, or black and white. 



There are differences of opinion as to their food. Although called Ant- 

 birds, it has been asserted by Belt and other naturalists, who have seen them at 

 home, that they never feed on ants, and when found in attendance on the ant 

 armies so often met with in the tropical forests it is for the purpose of feeding 

 on the insects started up by the advancing hosts and not on the ants themselves. 

 On the other hand, an equally good observer, Dr. C. W. Richmond, who made 

 observations on a number of species in the forests of Nicaragua, states that 

 three or four species of Ant-birds were almost always to be located about an 

 ant army, and appeared to be eating the ants, as examples of the latter were 

 found sticking to the mouths of the birds shot, while Sefior Alfaro, director of 

 the National Museum of Costa Rica, states that he has dissected the birds and 

 found their stomachs to contain ants. Furthermore, Dr. Richmond adds that 

 he found the birds as frequently attending the armies that go in solid lines of 

 only five or six inches wide as those covering a width of fifteen or twenty feet. 

 Most species, however, appear not to feed on ants, but on various other insects 

 with occasional seeds. The notes of the Ant-birds are various, sometimes being 



