12 



correct idea of the normal immigrations of these species 

 within this area. 



The results thus obtained would undoubtedly be of high 

 value, while a gradual broadening of such a detailed 

 enquiry to include eventually under the same system a 

 wider area, a larger number of species, and the Autumn 

 migratory movements as well as the Spring, should in our 

 opinion (provided no detail was sacrificed in widening the 

 field of observation) lead eventually to a better luiderstand- 

 ing of the main principles governing the Migration of 

 Birds. 



From the foregoing remarks it will be recognised that 

 we are unwilling to generalize to any great extent on the 

 results obtained from the records for 1905. A few points 

 of general interest, however, are dealt with below, but it 

 must be borne in mind that our conclusions are based 

 entirely upon the records for this one year. 



Of twenty-five species which have been sufficiently 

 recorded there are eighteen concerning which we have 

 been able to trace a varjdng number of definite immi- 

 grations, and only seven which appear to arrive gradually 

 without any marked immigration of numbers. 



These definite immigrations often lasted several days, 

 and were usually preceded and followed by the arrival of 

 stragglers. The number of individuals composing each 

 immigration varied, as did the number of immigrations of 

 each species. 



Even in the case of the largest immigrations, the records 

 show that the birds were travelling either singly, in 

 couples, or in small parties, and only in the cases of the 

 Swallow, House-Martin, Sand-Martin, and Swift were large 

 flocks reported. 



As will be seen in the detailed description of the 

 movements of each species, the birds of one immigration 

 often settled down with the birds of a former movement, 

 or part did so and the remainder passed on ; in other 

 instances the birds of one movement waited until the 

 arrival of the next immigrants and mingling with them. 



