STUDY OF BIRD BEHAVIOUR 003 



two species making for the advantage of one or both, and to the detriment of neither. 

 Examples: nnstle-thrush and chaffinch (vol. i. pp. 369-70). Parasitism is to the advantage 

 of the parasite and detriment of the host. Example : cuckoo (vol. ii. pp. 466-472). 



(h) Imitntivn.See above under " 1. General Classes of Behaviour." 



(i) Intercom in >< n "-'if ion. See above, " Song and Notes." 



11. Migration. (a) General. What is the impulse that prompts the bird to migrate ? Is 

 the impulse to depart and in a given direction instinctive ? If so, origin of instinct ? How are 

 birds guided to their destination ? 



(b) P'lrtirnl'i,: Date, hour, place. Number of individuals. Direction of flight, height, 

 speed. Sex of the successive arrivals of the same species. Adult, immature, or birds of 

 year. Wind or weather. Perils. Behaviour on arrival. Behaviour previous to departure. 

 Literature : Annual Reports of the British Ornithological Club ; Eagle Clarke, Studies in 

 Migration, 2 vols. (Gurney and Jackson) ; T. A. Coward, Migration of Birds, 1912 (Cambridge 

 Manuals of Science) ; Lloyd Morgan, Habit and Instinct, pp. 256-261. Latter two best for 

 general questions. 



12. Geographical Distribution. Added for sake of completeness, though not falling 

 under the head of behaviour. 



(a) Local L int. Exact descriptions of rare birds noted. Dates. Place seen. 



(b) Local map showing the distribution of the bird life in a given area all through the 

 year. Also approximate number of resident species, summer visitors, etc. Ring all young in 

 area, and adults if. they can be caught. Map the boundaries of nest-areas and feeding-areas of 

 species having such (see vol. i. p. 432). Flight lines. Roosts. Daily movements. 



