THE BOOK OF MIGRATORY BIRDS 55 



of their nests, impressing these upon their memory, then 

 discovering others further removed, and so on. Supported 

 by this knowledge of stations where food may be obtained, 

 the young birds are now left to their own resources to find 

 the way to their winter quarters. 



It may not be out of place here to refer to the inexplicable 

 manner in which dogs are able to find their way back to 

 their homes from very long distances. A friend of the 

 writer had occasion to send a dog by train on a long 

 journey, at the end of which, however, he managed to 

 escape, reappearing a few days after in a very emaciated 

 condition, having scampered the sixty or more miles 

 without food till the homestead was reached. Another 

 instance, a pet dachshund, about a year old, was put into a 

 sack on the estate of its owner, and conveyed in a close 

 cart to a farm miles away. Arrived at its destination, the 

 dog was liberated, but disappeared, and was back home 

 again before the conveyance returned ! Some farm hands 

 stated that the animal was seen going " as the crow 

 flies" across ditches and through hedges in a direct line 

 for home. 



On the trackless plains of North America cattle, after 

 having been driven for hundreds of miles, have .followed 

 the same method of returning, oft-times through brush- 

 wood and dense forests. 



So far, mention has been made of the land routes of the 

 migratory species. It is now my intention to bring under 

 the reader's notice a theory which has been established to 

 explain the crossing of wide seas by this host, more 

 especially in relation to the occurrence of American birds 

 in Europe. 



As already intimated, it was considered absolutely 

 impossible for a bird to traverse a stretch of water at least 

 sixteen hundred miles in breadth, which is the extent of 

 the Atlantic between Newfoundland and Ireland. Hence 

 it was believed that the only way in which it could accom- 

 plish this journey was by making use of what are called 

 "diluvial land bridges." These at the present day are 



