IOWA ACADEMY OF SCIENCE 
179 
quantity of such material left there by a freshet; and many more examples 
might be given. 
Several birds that build nests of the ordinary type frequently choose a 
situation that is inaccessible to reptiles and small mammals. For example, the 
two Tanagers PJioenicotJiraupis salvini and Eucometis spodocepTiala, and the 
Grosbeak Cyanocompsa concreta, favor certain small palms which are densely 
clothed with long, slender, needle-like spines. 
Nothing need be said in regard to nests placed in cavities, either natural 
or excavated by the birds, except in those curious instances where the nest of a 
species of termite or “white ant” is used for this purpose. These nests are coni- 
cal to nearly spherical in form, and from a few inches in diameter to the size 
of a barrel. They are commonly built on large branches some distance from the 
ground. In these structures, which are composed mainly of fine particles of 
wood cemented together to form the walls of small, intricately winding passages, 
the two Trogons, T. massena and T. melanocephalus, excavate holes for their 
nests. The hole is begun near the bottom and leads upward to about the center 
of the cone, where it expands into a large chamber. The birds are absolutely 
dependent on the insects for their nesting cites, which are remarkably safe 
from the attack of enemies. Without some such fortunate means of securing a 
rapid increase it is difficult to see how birds so feeble and of such low intelli- 
gence as these Trogons could long survive. The nest of the same species of 
termite also furnishes homes occasionally for certain Parrots and apparently 
always for the Paroquet, Conurus aztec, though these species excavate from the 
top instead of the bottom of the nest, and it is doubtful whether they do not 
sometimes occupy holes made in the termites’ nests by other animals. 
Most nests of the third type, such as those of the Yireonidae and species of 
Icterus, require no special mention. Though not precisely of this type, we may 
place here the wonderful nests of the Oropendolas, Gymnostinops and allied 
genera. Perhaps no birds’ nests of tropical America are better known than 
these; it is, therefore, sufficient to say that probably they are absolutely un- 
troubled by enemies, if we except the parasitic Rice Grade, Cassidix. 
Manikins of the genera Manacus and Pipra make small shallow nests of ex- 
tremely slight structure, and in the case of P. mentalis several dry leaves are 
hung loosely on the outside, which serve as a very effectual disguise. In both 
instances the nest is usually suspended near the end of a long, slender branch, 
inaccessible to most reptiles. 
Two Hummingbirds of the genus Phaethornis suspend their nest from the under 
side of a drooping palm leaf near the tip of one of the terminal pinnules. These 
are somewhat concave, so that the nest is attached by about one-half its cir- 
cumference along one side, the other side remaining free. In such a position 
even the nimblest lizard would find it very difficult to reach; yet a further pre- 
caution is taken by attaching to the bottom of the delicate structure, by means 
of spider webs, shreds of coarse bark, dry leaves, bits of rotten wood, etc., so 
that the whole nest is sometimes more than half a foot long, and closely re- 
sembles a bit of loose rubbish caught on the end of the leaf. 
It is in nests of the fourth class that we find the most striking examples of 
protective adaptation, and these for the most part in the great family of Tyran- 
nidae. 
The nest of the splendid Royal Flycatcher, OnycTiorhynchus, is no less re- 
markable than the bird. It is a fusiform structure, sometimes two feet in length. 
