BIRD CRADLES. 99 
catkins. The oven-bird’s hut is generally intermeshed with fruit- 
ing stems of urn moss, with their dried spore-caps. The Nash- 
ville warbler is partial to a mesh of pine needles'and horse-hair; 
while the purple finch considers hog-bristles and horse-hair a 
more suitable compound. The Kentucky warbler, and various 
other warblers, show a preference for the pith of weeds. Per- 
haps the prairie warbler has discovered some rare virtue in cast- 
off caterpillar skins that ordinary humanity cannot guess, its nest, 
I am told, usually showing a penchant towards this singular in- 
gredient. 
But this bird is not alone in this odd choice, of which others 
of the warblers and the vireos occasionally avail themselves. In 
addition to spider silk, and cocoon silk, I have discovered evi- 
dences that the web-tent of the apple-tree caterpillar is occasion- 
ally raided for material, having identified numbers of the cater- 
pillar skins among the web meshes of the vireos and redstart. 
The oriole visits the web-nest too, but on a different errand for 
her cradle. I once observed one of these birds mysteriously pry- 
ing about one of these tents. It left me hardly time to guess its 
object, but quickly thrust its head through the silken walls and 
took its pick of the fattest caterpillars in the squirming interior, 
carrying them to what it evidently considered as more appropri- 
ate surroundings in the hang-nest above. I once found a nest 
of the red-eye which exhibited a marked entomological preference, 
being composed largely of the hairy cocoons of the small tussock- 
moth, and conspicuously decorated with a hundred or more of the 
black skins of the aztzopa caterpillar, of all ages. What a singu- 
lar waste of energy one would naturally think was here revealed 
in the search for a material which at best must be a rare in- 
gredient in the wild gleaning. But the inference does injustice 
to the bird’s intelligence. Assuming that there is an advantage 
in the material, and granting the bird even a school-boy’s knowl- 
edge of the habits of a conspicuous insect, few substances could 
be acquired at a less expense of time than these withered skins; 
for the caterpillars of the azt:ofa live in swarms of hundreds, 
sometimes of thousands, in the elms and swamp-willows, and 
