Sometimes a dozen caciques will hang their nests in close proximity to a wasps' nest, as if for additional protection. A cacique's nest hangs like a grass rope, with a commodious purse at its lower end, entered by a narrow perpendicular slit a foot or so above the terminal facilities. It is impossible to achieve one of these nests without either shooting off the limb to which it hangs, or felling the tree. If it hangs low enough a charge of coarse shot usually will cut the limb, but if high, cutting it down with a rifle bullet is a more serious matter.
[Illustration with caption: HANGING NEST OF THE BALTIMORE ORIOLE
(From the "American Natural History")]
[Illustration with caption: GREAT HANGING NESTS OF THE CRESTED
CACIQUE As seen in the delta of the Orinoco Rover, Venezuela.]
To our Zoological Park visitors the African weaver birds are a wonder and a delight. Orioles and caciques do not build nests in captivity, but the weavers blithely transfer their activities to their spacious cage in our tropical-bird house. The bird-men keep them supplied with raffia grass, and they do the rest. Fortunately for us, they weave nests for fun, and work at it all the year round! Millions of visitors have watched them doing it. To facilitate their work the upper half of their cage is judiciously supplied with tree-branches of the proper size and architectural slant. The weaving covers many horizontal branches. Sometimes a group of nests will be tied together in a structure four feet long; and it branches up, or down, or across, seemingly without rhyme or reason.
Some of the weavers, which inhabit Africa, Malayana and Australia, are "communal" nest-builders. They build colonies of nests, close together. Imagine twenty-five or more Baltimore orioles massing their nests together on one side of a single tree, in a genuine village. That is the habit of some of the weaver birds;—and this brings us to what is called the most wonderful of all manifestations of house-building intelligence among birds. It is the community house of the little sociable weaver-bird of South Africa (Philetoerus socius). Having missed seeing the work of this species save in museums, I will quote from the Royal Natural History, written by the late Dr. Richard Lydekker, an excellent description: —This species congregates in large flocks, many pairs incubating their eggs under the same roof, which is composed of cartloads of grass piled on a branch of some camel- thorn tree in one enormous mass of an irregular umbrella shape, looking like a miniature haystack and almost solid, but with the under surface (which is nearly flat) honeycombed all over with little cavities, which serve not only as places for incubation, but also as a refuge against rain and wind.
"They are constantly being repaired by their active little inhabitants. It is curious that even the initiated eye is constantly being deceived by these dome-topped structures, since at a distance they closely resemble native huts. The nesting- chambers themselves are warmly lined with feathers."
Here must we abruptly end our exhibits of the intelligence of a few humble little birds as fairly representative of the wonderful mental ability and mechanical skill so common in the ranks of the birds of the world. It would be quite easy to write a volume on The Architectural Skill of Birds!
Now, let us look for a moment into the house-building intelligence and skill of some of the lower tribes of men. Out of the multitude of exhibits available I will limit myself to three, widely separated. In the first place, the habitations of the savage and barbaric tribes are usually the direct result of their own mental and moral deficiencies. The Eskimo is an exception, because his home and its location are dictated by the hard and fierce circumstances which dictate to him what he must do. Often he is compelled to move as his food supply moves. The Cliff-Dweller Indian of the arid regions of the Southwest was forced to cliff- dwell, in order to stave off extermination by his enemies. Under that spur he became a wonderful architect and engineer.
For present purposes we are concerned with three savage tribes which might have been rich and prosperous agriculturists or herdsmen had they developed sufficient intelligence to see the wisdom of regular industry.
Consider first the lowest of three primitive tribes that inhabit the extreme southern point of Patagonia, whose real estate holdings front on the Strait of Magellan. That region is treeless, rocky, windswept, cold and inhospitable. I can not imagine a place better fitted for an anarchist penal colony. North of it lie plains less rigorous, and by degrees less sterile, and finally there are lands quite habitable by cattle-and-crop-growing men.