332 Mr. Joseph I. S. Whitaker on the 



irregular intervals, varying greatly in their numerical import- 

 ance, as well as in their extension and duration. The 

 invasion of the past year, however, has been of such magni- 

 tude and so wide-spread that it cannot fail to have attracted 

 the attention of most ornithologists in our own country, as 

 well as abroad. 



So far as I am aware, no Report of a comprehensive 

 nature, embracing the whole of the European Continent, has 

 as yet been published regarding this highly interesting 

 ornithological event, although I understand that at least one 

 such Report is in course of preparation on the Continent, 

 and we m;iy therefore shortly expect to be placed in possession 

 of full details and much valuable information on the subject. 

 Meanwhile I may say that some interesting local notes and 

 letters regarding the course and progress of the invasion have 

 appeared from time to time during the past few months, in 

 England as well as on the Continent, and some noteworthy 

 particulars have been obtained and recorded concerning it. 



Foremost among these particulars, so far as relates to our 

 own country, may be mentioned those published in 'British 

 Birds/ and specially some notes by Mr. H. F. Witherby in 

 the November and December parts of that journal, the latter, 

 moreover, being accompanied by a series of maps, cleverly 

 drawn up by Commander Lynes, illustrating the extent and 

 progress of the invasion of Crossbills in the British Islands. 

 Letters have also appeared from time to time in the ' Field ' 

 recording the occurrence of this species in various parts of 

 the United Kingdom and abroad *. 



In Germany, as well as in Austro-Hungary, and generally, 

 I may say, throughout Central Europe, our brother orni- 

 thologists have not been idle in collecting notes and 

 information regarding the unusual appearance of Crossbills 

 in their respective countries. 



In France an inquiry into the subject was opened in the 

 columns of the ' Revue franchise d'Ornithologie ' last autumn, 

 and some interesting information has been obtained. 



* The details given in the 'Annals of Scottish Natural History' for 

 1909 and 1910 should also be consulted. — Edd. 



