Mar., 1910 EFFECT OF ENEMIES ON NESTING HABITS OF HONDURAS BIRDS 
57 
stream, from four to fifteen feet from the water. The greatest diameter is a little 
below the middle, and at this point the cavity is situated, which is entered by a 
small hole. The nest is composed of coarse fibrous material and covered over the 
outside with dry leaves, leaf stems, and large twigs, some of the last a foot or more 
in length. The whole affair in almost every detail so closely resembles a small 
mass of debris left by a retreating flood, as to deceive the keenest enemy. Fur- 
thermore, the location assists greatly in the disguise, the nest appearing to be but 
one among thousands of such masses entangled in the vegetation overhanging the 
stream. Add to this the difficulty any reptile or mammal would experience in 
reaching it, even were its nature known, 
and we have a most striking example of 
protective adaptation. 
Todirostrum cinereum and some other 
Tyrannidae make nests of precisely the 
same style as that of Onychorhynchus. 
That of T. cinereum is much less fre- 
quently built over a stream and is com- 
posed of finer material, often with so much 
cottony substance interwoven as to give 
it the appearance of a colony of “tent- 
caterpillars.” (See Fig. 18.) 
The nests of two other small flycatchers, 
Todirostrum sc/iistaceiceps and Oncostoma 
cinereigulare, are also suspended by the 
top from small branches and entered by a 
hole at the side, but are somewhat pear- 
shaped. They are built but two or three 
feet from the ground, and if they are as 
inconspicuous to the reptilian as to the 
human observer, they are comparatively 
safe. (See Fig. 19.) 
Rhynchocyclus is a genus of small fly- 
catchers of obscure coloring and ordi- 
nary habits, noteworthy only for their 
curious nests, which are perhaps among the 
most remarkable examples of protective 
adaptation known. The nest of R. ciner- 
eiceps is built from ten to thirty feet above 
the ground, or water, as it frequently Fig. 19. nest of the seate-headed 
overhangs a stream. In shape it resembles tody todirostrum 
an old shoe, or rather moccasin, sus- 
pended by the top with the entrance at the toe, and a narrow passage leading over 
the instep to the heel, where the main cavity is situated. It is composed of some 
kind of aerial roots — long, fine black fibers resembling horse hair. It usually 
hangs from a long, slender branch of one of those myrmecophilous acacias, 'whose 
stout double spines are hollow and inhabited by ants. The thorns are very nu- 
merous and the ants are extremely irritable and armed with formidable stings, 
equal in effectiveness to that of the bumble bee. The thorns alone would make 
the ascent of the tree by an animal of any size very difficult, but the presence of 
the ants renders it absolutely impossible. But this is not all. A species of hornet 
frequently makes its nest, a large conical or oval structure, in the same tree, and 
