4o8 THE BIOLOGY OF BIRDS 



put a tail to the narrative. They say, that in addition to 

 its office of leech-catcher to the crocodile, it occasionally 

 does happen that the zic-zac — so called from its note of 

 alarm — in searching for the leeches, finds its way into the 

 reptile's mouth when the latter is basking on a sand-bank, 

 where it lies generally with its jaws wide apart. Now this 

 is possible and likely enough, but the captain of our boat 

 added, that occasionally the crocodile falls asleep, when 

 the jaws suddenly fall, and the zic-zac is shut up in the 

 mouth, when it immediately prods the crocodile with its 

 horny spurs, as if refreshing the memory of his reptilian 

 majesty, who opens his jaws and sets his favourite leech- 

 catcher at liberty " (" Notes of a NaturaHst in the Nile 

 Valley and Malta," 1870). 



§ 6. The Hand of Man on Birds 



When prehistoric man found his way to Scotland, 

 perhaps ten thousand years ago, the country was recovering 

 from the Great Ice Age which had killed off almost ever}' 

 living creature. For many years the country had been 

 in process of restocking by animal-immigrants from the 

 South of England, and from what, in our insulation, we 

 now call the Continent, Scotland was then a smaller 

 country than it is to-day, for the sea stood at the level of 

 " the Fifty-Foot Beach " and the estuaries reached far 

 inland. " It was a country," we read, " of swamps, low 

 forests of birch, alder, and willow, fertile meadows and 

 snow-clad mountains," into which Neolithic Man penetrated 

 — a " long-headed, square-jawed, short, but agile-limbed, 

 hunter and fisherman. There were no domesticated 

 animals in those days, nor any dubious aliens like rabbits 

 and rats. But there were elk and reindeer, wild cattle, 

 wild boar, perhaps wild horses, a fauna of large animals 

 on which lynx, brown bear, and wolves levied toll. In 

 all likelihood, the marshes resounded to the boom of the 

 bittern, and the plains to the breeding-calls of the crane 

 and the great bustard." 



