Boot! I : Bird Migration. 165 



Swallow and the Chiffchaff have each required two maps. A 

 table g'iving- the weather and wind conditions prevailing- on each 

 side of the Eng-lish Channel from April 7th to May loth, and 

 showing at the same time the number of immig-rations noted each 

 day, is a valuable addition. From these it would appear that the 

 chief periods for mig^rants crossing" the Channel in 1905 were 

 respectively April 9th to 12th, April 26th to 28th, and May 7th 

 to 9th, almost irrespective of weather conditions. The map, 

 reproduced by the permission of the committee (Plate XII.), 

 illustrates the four chief immig-rations of the House Martin, 

 as g-athered from the records for this species. Leaving- out 

 the early stragg-lers (among-st which are Radnor April 3rd 

 and Yorkshire April nth), it would appear that the House 

 Martins arrived at certain parts of the south coast onlyy 

 none having- been noted in the centre [i.e.^ the Hampshire 

 and Dorset coasts) This was in g-reat contrast to that 

 of the Swallow, which appeared to arrive in a broad front 

 along- the whole of the south coast. The respective immi- 

 g-rations of the House Martin made their appearance on the 

 south coast of Eng-land as follows : April loth to i6th, April 

 i8th and 19th, and April 24th to 27th. The birds forming; the 

 above three immig-rations can be traced northwards throug-h the- 

 country by the reference dates on the map. The fourth immig-ra- 

 tion was noticed on the coasts of Sussex and Kent on May 7th 

 and 8th, but the course of this last batch was not traceable 

 further, and these birds probably passed forward to more 

 northern breeding- g-rounds than Eng-land. 



Besides a short written account, a ' Chronolog-ical Summary 

 of the Records ' is published with each species. We think it 

 would have been better to have published all the reliable records- 

 in full, and more particularly all those that are shown on the 

 maps. These omissions render comparisojis and deductions 

 very confusing- to the student. Using- selected records also is 

 liable to g^ive a wrong; impression, and to bring- to mind the 

 saying that 'Statistics can be made to prove anything-.' The 

 altitude above sea level of the various observatory stations 

 would have been an improvement. The bare description 

 ' Yorkshire,' for instance, is very vague, when we know that 

 the arrival and settling down of many species is governed to a 

 certain extent by the varied geographical ' face ' of our county 

 of 'broad acres.' A list of those who made the observations 

 would have added additional value and authority to the records. 

 The committee, however, are to be complimented on the success. 



1906 May I. 



