the season being early or late, in illustration of which, it may be 

 stated, that the wet and backward weather throughout last spring 

 (1867) delayed the arrival of the Warblers fully two weeks. It 

 should also be mentioned, that the abundance or scarcity of each 

 species has reference, unless when otherwise noted, not to any 

 special locality, but to the whole district represented. 



The diffusion of well authenticated information regarding the 

 distribution of American birds, is yet a matter for future observa- 

 tion. There have been, no doubt, many important contributions 

 on this subject, of late years, yet the field is so extensive that many 

 years must elapse before we can lay claim to a thorough knowledge 

 of many important particulars, which patient research and well- 

 timed energy alone can solve. The author of the present little work, 

 while claiming for it the merit of careful observation, extending 

 over a period of several years, at the same time believes the plan 

 of the Catalogue to be capable of attaining more useful results, if 

 enlarged in proportion to the nature of the districts investigated. 

 It is, therefore, to be hoped that accurate observers may undertake 

 similar records, by means of which the next great work on the 

 ornithology of our country may contain a better collection of facts, 

 representing the phenomena of the remoter districts, than has yet 

 been obtained. 



While making the usual acknowledgments to those who have so 

 obligingly furnished the author with information, it gives him much 

 pleasure to record his additional obligations to his friend, Mr 

 Thomas S. Hutcheson, for his valuable services in superintending 

 the work when passing through the press, and for other necessary 

 aid, which, at this distance, is most thankfully appreciated. Nor 

 must he omit to thank another friend and correspondent — Mr 

 Robert Gray, Secretary to the Natural History Society of Glasgow 

 — for useful notices regarding some of the birds of the remoter 

 Hebrides of Scotland, between which district and some parts of 

 our own continent there would appear to be an occasional inter- 

 migration of species. On this subject, however, the author 

 may at a future time, conjointly with that gentleman, bring 

 all the ascertained facts and observations under the notice of 

 ornithologists in a separate form. 



W. P. T. 



Philadelphia, January, 1869. 



