THE "CORROS," OR MASSING OF WILDFOWL IN SPRING FOR THEIR NORTHERN
MIGRATION
The withdrawal of the wildfowl at the vernal equinox affords an
unequalled scenic display. It forms, moreover, one of those rare
revelations of her inner working that Nature but seldom allows to man.
Her operations, as a rule, are essentially secretive. A little may be
revealed, the bulk must be inferred. Here, for once, a vast revolution
is performed in open daylight, _coram populo_--that is, if the authors
and a handful of Spanish fowlers be accepted as representative, since no
other witness is present at these scenes enacted in remote watery
wilderness.
Up to mid-February the daily life of the marisma continues as already
described. From that date a new movement becomes perceptible--the
seasonal redistribution. Daily there withdraw northward bands and
detachments counting into thousands apiece. But no vacancy occurs since
their places are simultaneously filled by corresponding arrivals from
beyond the Mediterranean.
It is at this precise epoch that there occurs the phenomenon of which we
have spoken.
Towards the close of February, dependent on the moon, a marked climatic
change takes place. A period of sudden heat usually sets in--a sequence
of warm sunny days, breathless, and at noontide almost suffocating. But
each afternoon with flowing tide there arises from the sea a S. W.
breeze, gentle at first and uncertain but gaining strength with the
rising flood.
Already, shortly before this change, the duck-tribes had partially
relaxed their full mid-winter activities--owing to abundant spring
growths of food-plants, had become more sedentary; if not sluggish, at
least reluctant to move. After the brief morning-flight not a wing
stirred. But now, scan the mirror-like surface of some great _lucio_
and you will recognise a new movement distinct and dissimilar from
regular hibernal habit. There float within sight (and the same is
happening at a score of places beyond sight) not only the usual loose
flotillas, but three, four, or five concrete assemblages of densely
massed fowl whose appearance the slightest scrutiny will differentiate
from the others. These are not sitting quiescent. The binoculars
disclose a scene of perpetual motion, well-nigh of riot--one might be
regarding a feathered faction-fight. Hundreds of units fight, splash,
and chase, or throw up water with beating wings till surf and spray half
conceals the seething crowd. That flicker of pinions and flying foam
are, moreover, accompanied by a chorus of myriad notes--a babel of
twirling sound blended in rising and falling cadences, comparable only
to the distant roar of some mighty city. A more singular spectacle we
have not encountered.
Inquiry from one's companion elicits the reply that these assemblages
are _hechando corros para irse_ (literally, "forming choruses
preparatory to departure")--an expression which conveyed no more
significance to us than it can to the reader.[64] We decided to return
at daybreak to see this thing through, and after watching the phenomenon
a score of times can now explain it.
During the morning hours there are established focal points whereat
assemble those units already affected by the emigrant furor. These (at
first, perhaps, but a score or two) rapidly increase in numbers till
each focus becomes the nucleus of a corro. The seasonal infection
spreads, and as its influence impregnates the surrounding masses, these,
singly or in scores or hundreds as the passion seizes them, hasten to
join one or other of the mobilising army-corps. Within an hour or two
the insignificant original nucleus has developed into a vast host all in
a ferment of agitation, and being constantly reinforced by buzzing
swarms of recruits from without.
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.
[Illustration: REED-BUNTING
A winter visitor to the marismas.]
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.
The most favourable time for the assembling of corros is on those days
when great heat and calm at midday is succeeded towards evening by an
extra strong sea-breeze. On such occasions very large numbers will leave
between sundown and dark. Northerly winds will almost absolutely arrest
the exodus.
For the season of 1900-1901 our game-books showed a total of 4849
wildfowl (4674 ducks and 175 geese)--a record for which we were
good-humouredly taken to task by our venerable friend the late Canon
Tristram, who thought it looked excessive. The figures certainly are
big, but the next entry in the book reads:--
_March 15._--This evening between fifty and seventy _corros_ left
within half an hour--say 50,000 to 70,000 ducks. Next morning the
marisma appeared as full as ever.
Our toll of 5000 seemed by comparison but as a drop in the bucket!