CHAPTER XXXVlll 



THE "CORROS," OR MASSING OF WILDFOWL IN 

 SPRING FOR THEIR NORTHERN MIGRATION 



The withdrawal of the wildfowl at the vernal equinox afibrds an 

 unequalled scenic display. It forms, moreover, one of those rare 

 revelations of her inner workino- 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 o;ainino; strens^th with the risinsj 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 



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