Hutton. — Our Migratory Birds. 263 



But this faculty is not unerring, even with migratory 

 birds, as is shown by the number of stragglers which have lost 

 their way. Most of these no doubt perish at sea, for they 

 have often been known to take refuge on ships ; and perhaps 

 none regain their route after having once lost it. 



There still remains one more question to ask. Why 

 should some of the shore-birds and cuckoos migrate to us and. 

 not swallows, which are certainly quite as capable of under- 

 taking the journey ? Possibly the geological history of birds 

 may help us to answer this question. 



Eemains of several kinds of Limnicolce, — three sandpipers 

 and two rails — have been described from the Upper Cre- 

 taceous rocks of North America, so that they are among the 

 oldest of carinate birds. In the gypsum of Montmartre, in 

 France — which belongs to the Oligocene period — a godwit 

 (Liviosa) has been found, together with a few land-birds, one 

 of which is a cuckoo. The first known swift (Cypselus) is 

 from the Miocene, and we do not find swallows or martins 

 (Hirundo) until the Pleistocene. Now, is this association 

 of our two principal migratory birds — the godwit and the 

 cuckoo — in the Montmartre gypsum, and the absence of the 

 remains of swifts and swallows from all Oligocene rocks, 

 merely a coincidence, or are the facts connected? Is it 

 because swifts and swallows did not live with cuckoos and 

 godwits in Oligocene times that they do not now accompany 

 them in their migrations to New Zealand ? 



No doubt negative palaBontological evidence must be used 

 with great caution, but it seems to me probable that the 

 godwit and cuckoo migrated to New Zealand at a time when 

 no swallows were in existence, and that the original land 

 bridge had been completely broken down before the first of 

 the swallows arrived in Australia from Asia. I therefore sup- 

 pose that migration to and from New Zealand commenced in 

 the Eocene period, when the land stretched away to the 

 north-w<est nearly to New Guinea — a time when, although 

 New Zealand was not actually joined to the mainland, it 

 must have approached pretty close to it. 



In conclusion, I may perhaps be able to make some 

 useful and practical deduction from this slight investigation. 

 Can we introduce swallows and other insect-eating migratory 

 birds into New Zealand with success ? 



It will be evident from what has been said that the 

 naturalisation in New Zealand of migratory birds is im- 

 possible unless they abandon their migrating habits, for we 

 cannot give them a new instinct and teach them how to cross 

 the sea. Small flocks of the tree-martin of Australia have 

 been seen several times in New Zealand, and no doubt they 

 also often came before there were any settlers to record their 



