Thus, their natural political unit was the little matrilineal clan. Such semiformal blood groups, almost free of government, were rather loosely organized into the Great Flock. And the Flock’s raison d’etre — apart from minor inter-sept business at home — was simply to increase the safety of all when every Diomedean on Lannach flew south for the winter.

Or came home to war!

“It is interesting,” murmured Van Rijn, half in Anglic. “Among our peoples, like on most planets, only the agriculture folk got civilized. Here they make no farms at all: the big half-wild hornbeast herds is closest thing, nie? You hunt, berrypick, reap wild grain, fish a little — yet some of you know writing and make books; I see you have machines and houses, and weave cloth. Could be, the every-year stimulus of meeting foreigners in the tropics gives you ideas?”

“What?” asked Trolwen vaguely.

“Nothings. I just wondered, me, why — since life here is easy enough so you have time for making civilization — you do not grow so many you eat up all your game and chop down all your woods. That is what we called a successful civilization back on Earth.”

“Our numbers do not increase fast,” said Trolwen. “About three hundred years ago, a daughter Flock was formed and moved elsewhere, but the increase is very slow. We lose so many on the migrations, you see — storm, exhaustion, sickness, barbarian attack, wild animals, sometimes cold or famine—” He hunched his wings, the Diomedean equivalent of a shrug.

“Ah-ha! Natural selection. Which is all well and good, if nature is obliging to pick you for survival. Otherwise gives awful noises about tragedy.” Van Rijn stroked his goatee. The chins beneath it were getting bristly as his last application of antibeard enzyme wore off. “So. It does give one notion of what made your race get brains. Hibernate or migrate! And if you migrate, then be smart enough to meet all kinds trouble, by damn.”

He resumed his noisy walk up the trail. “But we got our troubles of now to think about, especially since they are too the troubles belonging with Nicholas van Rijn. Which is not to be stood. Hmpf! Well, now, tell me more. I gather the Fleet scrubbed its decks with you and kicked you up here where the only flat country is the map. You want home to the lowlands again. You also want to get rid of the Fleet.”

“We gave them a good fight,” said Trolwen stiffly. “We still can — and will, by my grandmother’s ghost! There were reasons why we were defeated so badly. We came tired and hungry back from ten-days of flight; one is always weak at the end of the springtime journey home. Our strongholds had already been occupied. The Draka flamethrowers set afire such other defenses as we contrived, and made it impossible for us to fight them on the water, where their real strength lies.”

His teeth snapped together in a carnivore reflex. “And we have to overcome them soon! If we don’t we are finished. And they know it!”

“I am not clear over this yet,” admitted Van Rijn. “The hurry is that all your young are born the same time, nie?”

“Yes.” Trolwen topped the rise and waited beneath the walls of Salmenbrok for his puffing guest.

Like all Lannachska settlements, it was fortified against enemies, animal or intelligent. There was no stockade — that would be pointless here where all the higher life-forms had wings. An average building was roughly in the shape of an ancient Terrestrial blockhouse. The ground floor was doorless and had mere slits for windows; entrance was through an upper story or a trap in the thatched roof. A hamlet was fortified not by outer walls but by being woven together with covered bridges and underground passages.

Up here, above timberline, the houses were of undressed stone mortared in place, rather than the logs more common among the valley clans. But this thorp was solidly made, furnished with a degree of comfort that indicated how bountiful the lowlands must be.

Van Rijn took time to admire such features as wooden locks constructed like Chinese puzzles, a wooden lathe set with a cutting edge of painstakingly fractured diamond, and a wooden saw whose teeth were of renewable volcanic glass. A communal windmill ground nuts and wild grain, as well as powering numerous smaller machines; it included a pump which filled a great stone basin in the overhanging cliff with water, and the water could be let down again to keep the mill turning when there was no wind. He even saw a tiny sail-propelled railroad, with wooden-wheeled basketwork carts running on iron-hard wooden rails. It carried flint and obsidian from the local quarries, timber from the forests, dried fish from the coast, furs and herbs from the lowlands, handicrafts from all the island. Van Rijn was delighted.

“So!” he said. “Commerce! Yea-are fundamentally capitalists. Ha, by damn, I think soon we do some business!”

Trolwen shrugged. “There is nearly always a strong wind up here. Why should we not let it take our burdens? Actually, all the apparatus you see took many lifetimes to complete — we’re not like those Drakska, wearing themselves out with labor.”

Salmenbrok’s temporary population crowded about the human, with mumbling and twittering and wing-flapping, the cubs twisting around his legs and their mothers shrieking at them to come back. “Ten thousand purple devils!” he choked. “They think maybe I am a politician to kiss their brats, ha?”

“Come this way,” said Trolwen. “Toward the Males’ Temple — females and young may not follow, they have their own.” He led the way along another path, making an elaborate salute to a small idol in a niche on the trail. From its crudity, the thing had been carved centuries ago. The Flock seemed to have only a rather incoherent polytheism for religion, and not to take that very seriously these days; but it was as strict about ritual and tradition as some classic British regiment — which, in many ways, it resembled.

Van Rijn trudged after, casting a glance behind. The females here looked little different from those in the Fleet: a bit smaller and slimmer than the males, their wings larger but without a fully developed spur. In fact, racially the two folk seemed identical.

And yet, if all that the company’s agents had learned about Diomedes was not pure gibberish, the Drak’honai represented a biological monstrousness. An impossibility!

Trolwen followed the man’s curious gaze, and sighed. “You can notice nearly half our nubile females are expecting their next cub.”

“Hm-m-m. Ja, there is your problem. Let me see if I understand it right. Your young are all born at the fall equinox—”

“Yes. Within a few days of each other; the exceptions are negligible.”

“But it is not so many ten-days thereafter you must leave for the south. Surely a new baby cannot fly?”

“Oh, no. It clings to the mother all the way; it is born with arms able to grasp hard. There is no cub from the preceding year; a nursing female does not get pregnant. Her two-year-old is strong enough to fly the distance, given rest periods in which it rides on someone’s back — though that’s the age group where we suffer the most loss. Three-year-olds and above need only be guided and guarded: their wings are quite adequate.”

“But this makes much trouble for the mother, not so?”

“She is assisted by the half-grown clan members, or the old who are past childbearing but not yet too old to survive the journey. And the males, of course, do all the hunting, scouting, fighting, and so forth.”

“So. You come to the south. I hear told it makes easy to live there, nuts and fruits and fish to scoop from the water. Why do you come back?”

“This is our home,” said Trolwen simply.

After a moment: “And, of course, the tropic islands could never support all the myriads which gather there each midwinter — twice a year, actually. By the time the migrants are ready to leave, they have eaten that country bare.”