6 STUDIES IN BIRD-MIGRATION 



each one has been seen with the change as yet 

 incomplete. 



Passing now to the earliest years of Christian era, we 

 find that the Roman naturalist Pliny (a.d. 20-79), in his 

 Historia Natnralis (lib. x. cap. 24), has something to 

 say on the subject of bird-migration. His views, how- 

 ever, are mainly those of Aristotle. He informs us that 

 the CEnanthe (Wheatear) has its stated days for retire- 

 ment ; at the rising of Sirius it conceals itself, and at the 

 setting of that star comes forth from its retreat : this it 

 does, most singular to relate, exactly on both these days. 

 As to the Chlorion (Golden Oriole), it is not seen in 

 winter, but comes forth about the summer solstice. 

 Pliny states that Blackbirds, Thrushes, and Starlings 

 take their departure to neighbouring countries, but do 

 not lose their feathers, nor yet conceal themselves, as 

 they are often seen in winter. The Ring Dove also 

 takes its departure, but whither it goes is a matter of 

 doubt. Writing on the movements of the Stork and 

 Crane, he remarks that up to his time it has not been 

 ascertained from what place the Storks come, or whither 

 they go when they leave. There can be no doubt, he 

 tells us, that like the Cranes they come from a great 

 distance. Pliny repeats Aristotle's statements regarding 

 the transmutation of the birds already alluded to. 



There can be little doubt that the hibernation theory 

 owes its origin, to some extent, to the fact of Swallows, 

 Martins, and other migratory birds having been found 

 dead in holes in banks, etc., into which they had crept 

 for shelter from an outburst of inclement weather dur- 

 ing their sojourn in their native lands, which is not an 

 uncommon event. These were supposed to be the 

 remains of individuals which had died from natural 



