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-