All this procedure, remember, has been taking place during the blazing noontide heat. Now the hour is 2 P.M., and the first gentle breath of the daily sea-breeze—the viento de la mar—is becoming perceptible. This breeze springs from the S. W., and let us here admit that, being fowlers as well as naturalists, our observance of the phenomenon has usually been carried out upon a lucio which happens to terminate towards the N. E. in a long narrow bight fringed by tall reeds and bulrush, where, concealed in friendly covert, we can continue the observation while glancing along the barrel of a punt-gun. That secondary fact is merely incidental and, it so happens, facilitates the main object.
A mile to windward three such armies are mobilising separately within the scope of our view; and now the gentle force of that sea-breeze begins to impel those unconscious hosts, too preoccupied with all-absorbing passion to notice detail, directly towards the point whereat we lie concealed.
By this time the sun has three or four hours of declension and the thin dark line representing thousands of surging atoms has drifted down to within 200 yards. We can study at short range an amazing phenomenon. In weird exuberance they fight and flirt, chase, cherish, and flap till churned water flies in foam and a discordant roar of sibilant sound fills to the zenith the voids of space. The volume of voices defies description since these assembling multitudes belong to no single species, but include a promiscuous agglomeration of all that care to enlist, and each adds its own distinctive element to the general uproar.[65] Around the floating host new-comers buzz like swarming bees, each seeking some spot to wedge itself into the crowd.
To-night the main corro that we had been awaiting drifted past our front a trifle beyond effective range. The two that followed both “took the ground” and remained stationary, away to the right. The chance of making a great shot had failed; but we were content to watch the phenomenon to its finish.
Now the sun dips. The western sky is filled with golden glory; in twenty short minutes darkness will have enveloped the earth. Then in a moment, as by word of command, silence, sudden and impressive, reigns where just before that torrential babel had raged. Such, now, is the stilly silence that by comparison the pipe of a passing redshank sounds well-nigh scandalous! A few seconds pass. Then, dominated by a single impulse, the concentrated mass on our front rises simultaneously on wing. The spell of silence is broken; the roar of pinions reverberates far and wide. They’re off—bound for Siberia!
Yet unperplexed as though one spirit swayed
Their indefatigable flight.
Holding the same massed formation, the fowl in three or four broadening circles quickly attain a considerable altitude—say 100 yards—and then head away on their course, ALWAYS (so far as they remain visible) to the SOUTH-EAST—diametrically opposite to the direction one would expect. As in deepening darkness we set forth on our homeward voyage, the heaven above pulsates at intervals with the beating of wings as yet more north-bound corros pass overhead.
Certain notable facts are observable in this vernal exodus. For upwards of twelve hours prior to departure the outgoing fowl take no food. That period is devoted exclusively to preparation and overhaul, and to pairing. Plumage is preened and dressed till each unit is spick and span, speckless, and not a feather misplaced. All, moreover, are absolutely empty—in best and lightest travelling trim.
When ducks are acorrados—that is, formed into corros (the term is used thus in verb-form)—their normal watchfulness is relaxed. All thought and energy are concentrated on the impending event. Hence, at these periods they are apt to fall an easier prey to the fowler and on wholesale lines. The native gunners with their trained cabresto-ponies sometimes unite and enormous totals are secured as the result of a single joint broadside. The fowl thus obtained afford proof of the facts just stated, being all absolutely empty; besides which many different species will be killed at the one shot.[66] These men also state that the ducks start already paired and flying side by side; this, they say, explains the ferment and commotion of the previous hours—courting and sorting. Adult ducks, as previously indicated ([p. 110]), apparently pair for life; but since some species (such as wigeon) take at least two years to gain maturity, it is probable that the sexual phenomena which are so conspicuous in the corros represent the first pairing of the newly adult two-year-olds.