"Migrating," observed Huyghens. "I said they did. They're headed somewhere. Do you know, I doubt that it would be healthy for us to try to cross the plateau through such a swarm of sphexes?"
Roane swore, in abrupt change of mood.
"But the signal's still coming through! Somebody's alive over at the robot colony! Must we wait till the migration's over?"
"We don't know," Huyghens pointed out, "that they'll stay alive. They may need help badly. We have to get to them. But at the same time—"
He glanced at Sourdough Charley and Sitka Pete, clinging patiently to the mountainside while the men rested and talked. Sitka had managed to find a place to sit down, though one massive paw anchored him in his place.
Huyghens waved his arm, pointing in a new direction.
"Let's go!" he called briskly. "Let's go! Yonder! Hup!"
IV
They followed the slopes of the Sere Plateau, neither ascending to its level top—where sphexes congregated—nor descending into the foothills where sphexes assembled. They moved along hillsides and mountain-flanks which sloped anywhere from thirty to sixty degrees, and they did not cover much distance. They practically forgot what it was to walk on level ground. Semper, the eagle, hovered overhead during the daytime, not far away. He descended at nightfall for his food from the pack of one of the bears.