INTRODUCTORY. 3 



of south-west winds surcharged with moisture, a climate in 

 many respects unique, certainly more temperate by far than 

 that of any other, taking it all the year round. Of the 

 great changes that have of necessity passed over these 

 islands, then mainland, since the days when elephants 

 crashed through vast forests long since turned to coal, 

 while the hippopotamus basked in our streams, the huge 

 moose browsed on the forest-trees of Ireland, and graceful 

 palms and tree-ferns waved over the northern lochs, there 

 is here no need to speak. It is sufficient to note that Great 

 Britain is to-day the summer resort of tropical birds, the 

 winter-quarters of Polar waterfowl, all repairing hither, 

 year after year, those to reproduce their kind, these to 

 enjoy the food denied them in their natural home. So, too, 

 people who have resided in lands where the annual extremes 

 of mean temperature lie 150 apart, where even day and 

 night show a difference of 75, learn with the birds to 

 appreciate the much-abused British climate. As might, 

 however, be expected, there are not inconsiderable varia- 

 tions within the limits of these islands, the damp south- 

 west of England, and, still more, the rainy west of Ireland, 

 contrasting unmistakably with the drier eastern counties, 

 which, hotter in summer and colder in winter, possess a 

 climate far more closely approaching that of the Continent. 

 In addition to the chief islands of the group to wit, 

 Great Britain and Ireland there are a dozen other groups 

 of special interest to the naturalist, the Orkneys, Shet- 

 lands, Inner and Outer Hebrides, St Kilda, the Bass Hock, 

 the Fame Islands, the Channel Islands, the Scillies, Eockyll, 

 Lundy Island, the Isle of Wight, the Duke of Buccleuch's 

 gull-preserve on Walney Island, and, lastly, the Isle of Man. 

 Heligoland now lies, politically if not zoologically, outside 

 the region ; but all who are interested in its capabilities as 

 an observatory for the study of bird-migration will find an 

 excellent account in the late Dr Gaetke's book, 1 a transla- 

 tion of which has appeared in the English language. 

 1 Heligoland as an Ornithological Observatory. 



