VOL. vin.] A STUDY OF BIRD (ECOLOGY. 191 



on wide reading of bird-books and journeys to Heligoland 

 and South America. It depends on careful, accurate 

 and persistent watching in one place. 



Observations on similar lines with regard to less 

 sedentary species than Tits may be conducted through- 

 out the year, and at all times of day and night, for at 

 every time of year and at every time of day some birds 

 are moving, even though there may be brief seasons 

 when no great migratory flights are in progress. It is 

 not sufficient, however, to note the species seen on the 

 move or to note increase or decrease of species. The 

 exact number involved should be noted as far as possible, 

 also the direction of flight in the case of all birds flying 

 a considerable distance, as well as weather conditions, 

 type of country and any other circumstances, especially 

 botanical and entomological, likely to be of value. 

 What I would emphasize particularly is that every 

 flock of birds seen must be, as far as possible, accurately 

 counted. If it is a large flock a portion should be 

 counted and the total number estimated from this ; 

 or if occasional parties of one species continue to pass 

 for a long period, the obvious method is to count for 

 five minutes and later to count for another five, and 

 perhaps later repeat the process a third time. The 

 tendency to exaggerate can only be checked in this 

 way. My own experience is that a thousand birds are 

 very rarely to be seen together. One may see many 

 thousands of Guillemots and other sea-birds at their 

 breeding-haunts, and of Starlings at a large roost ; 

 otherwise I have never to my knowledge seen a thousand 

 birds at a glance. 



The lines of investigation which I have suggested 

 are of an ideal nature. No one could make such 

 thorough investigations without being able to devote 

 every moment of time to the matter. What is wanted 

 is, of course, that those who have any time which they 

 are anxious to devote to such study should direct their 

 exertions in such a way as to obtain the best results 



