This habit of picking up whatever may be lying on the ground anywhere near its habitation must cost much trouble.

For what purpose it is done, I am quite unable to form even the most remote conjecture: it cannot be for defence, because the rubbish is chiefly placed above the mouth of the burrow, which enters the ground at a very small inclination.

No doubt there must exist some good reason; but the inhabitants of the country are quite ignorant of it.

The only fact which I know analogous to it, is the habit of that extraordinary Australian bird, the Calodera maculata, which makes an elegant vaulted passage of twigs for playing in, and which collects near the spot land and sea-shells, bones, and the feathers of birds, especially brightly coloured ones.

Mr.Gould, who has described these facts, informs me, that the natives, when they lose any hard object, search the playing passages, and he has known a tobacco-pipe thus recovered.
The little owl (Athene cunicularia), which has been so often mentioned, on the plains of Buenos Ayres exclusively inhabits the holes of the bizcacha; but in Banda Oriental it is its own workman.
During the open day, but more especially in the evening, these birds may be seen in every direction standing frequently by pairs on the hillock near their burrows.