Xll INTRODUCTION. 



allowed, accidentally or designedly (vide p. 107), to escape; 

 and there are many birds, for example the Picida, whose 

 importation in cages rarely, if ever, occurs. 



Those who find it difficult to believe in the appearance of 

 Picus martins in England after so short a journey as the 

 passage of the German Ocean, must feel still greater difficulty 

 in admitting the claims of any American species of Picus to 

 a place in the British list. And yet there are records, ap- 

 parently trustworthy, of the capture of no less than three 

 different species of this genus in England (vide pp. 122, 123), 

 all of which are inhabitants of the New World. 



In attempting to ascertain the claims of such species as 

 these to be admitted in a list of British birds, there are two 

 difficulties which constantly beset the conscientious historian 

 who meets with records of their capture here. These are : 

 first, the published communications of over-zealous collectors, 

 who, anxious to record their possession of a species which 

 they deem rare, hasten to give it a name before they have 

 satisfactorily identified it ; and, secondly, the results of 

 the many attempts which unscrupulous dealers make (un- 

 fortunately too often with success) to palm off foreign species 

 upon unwary collectors, with the assurance that they have 

 been killed in some part or other of the British Islands. 

 There can be little doubt that many of such records, to which 

 of necessity reference has been made in the second part of 

 this work, are, for the reasons above mentioned, worthless, 

 although perhaps originally published in perfect good faith by 

 the owners of the specimens. It has been practically im- 

 possible, through lapse of time, death of parties, or ignorance 

 of their addresses, to test the value of every reported oc- 

 currence of rare visitants ; but yet, whenever this was 

 possible, it has- been done, and oftentimes with the best 

 results. In many cases where it could not be effected, the 



