° 1916 J Huxley, Bird-watching and Biological Science. 263 



been taught particular songs or dances, they will almost certainly 

 reproduce some phrases or motions of these. What they have 

 learned thus serves as a channel through which the emotion can be 

 liberated.) As examples of this in birds, we may take the song of 

 those species, like the common European Thrush {Turdus mvsicns) 

 or the Redbreast {Erithacus rubecula), which continue singing 

 almost or quite through the winter. The aerial tumblings of 

 Ravens, Curlews, Herons and other birds should also probably be 

 included here. 



If desired, other headings can of course be added, on such topics 

 as food-habits, migration, etc. One interesting point that has not 

 received much attention is the variation of habits in varieties of a 

 single species; e. g. the different songs of the Eastern and Western 

 Meadowlark {Sturnella magna and S. negleda). In Europe I have 

 noticed that the Marsh Tit {Parus palustris) has a long and quite 

 musical song on the Continent, while in England it restricts itself 

 to call-notes. 



The best method for keeping the actual field notes is to file them 

 in folders. Each folder has a number corresponding to the number 

 of the species in the card-index. The numbers used in the A. O. U. 

 Check-list may be used with advantage. In the folder the notes 

 had best be dated and arranged chronologically, and reference from 

 the cards to the notes will then be by date. 



Let me take a concrete case. In February of this year I have 

 been seeing a little of the earliest pairing-up habits of the Killdeer. 

 While the birds are still in flocks, and the majority of them still 

 far south of their breeding-places, this process is already beginning. 

 Most of the flocks are simply feeding and resting unconcernedly as 

 they have been doing all winter; but here and there one bird will 

 be seen flying up close to another, who in turn will usually take 

 wing and fly off, often to be pursued two or three times. A still 

 smaller proportion of the flock seems to be already paired, and may 

 be seen going through a ceremony together; I have not yet quite 

 got the details of this, but both birds seem to participate, walking 

 round and round each other in a strange formal way with heads 

 pointing in opposite directions and necks straightened stiffly out, 

 at the same time uttering a curious soft note. In passing, I may 

 say that the Killdeer should be a good species in which to study 



