echo to their calls long after the coyotes themselves had passed from
hearing.

The nights were getting warmer as we travelled south, but not so warm
that we were bothered with insects. The same reason accounted for the
absence of snakes or scorpions, for no doubt there were plenty of both
in warm weather in this dry country. When there was no wind, the
silence of the nights was impressive, with no sound save the lapping
of the water against the banks. Sometimes a bird in the trees above
would start up with a twitter, then quiet down again. On occasions the
air chambers in our boats would contract on cooling off, making a
noise like the boom of a distant gun, every little sound being
magnified by the utter stillness of the night.

There were other times when it was not so quiet. Hundreds of birds,
geese, ducks and mud-hens had been seen the last few days. Also there
were occasional cranes and herons, over a thousand miles from their
breeding place at the mouth of the Colorado. As dusk settled, we would
see these birds abandon their feeding in the mud, and line up on the
shore, or on an island, and go to sleep. Occasionally one of these
birds would start up out of a sound sleep with an unearthly squawk.
Possibly an otter had interrupted its dreams, or a fox had pounced on
one as it slept. It may be that it was only a bad dream of these
enemies that caused their fright, but whatever it was, that first call
would start up the entire flock and they would circle in confusion
like a stampeded herd of cattle, their discordant cries putting an end
to the stillness of the night. Finally they would settle down in a new
spot, and all would be quiet once more.

We saw a few birds that were strangers to us,--water birds which we