602 STUDY OF BIRD BEHAVIOUR 



Exact descriptions of the bodily movements both of nidicolous nestlings and fledglings 

 (e.g. thrush), and nidifugous chicks (e.g. waterhen), about to be fed. Are these movements 

 used in the adult stage for other purposes ? (e.g. quivering of wings of young about to be fed, 

 and of adult hen summoning mate for coition). Where on palate, etc., must there be stimulus 

 by food contact in order to provoke swallowing response ? Age at which young cease begging 

 for food. How begging checked by parents. 



(d) Methods of procuring food and drink. Exact descriptions. How far instinctive, 

 intelligent. For this observe young when first left to their own devices without chance of 

 imitation. Examples : Osprey (" Addenda," p. 619 of this vol.), jay and waterhen (Lloyd Morgan, 

 Habit and Instinct, pp. 56-57, 37-38). Observations under this head provide good material for 

 the relationship of behaviour and structure, on which see W. P. Pycraft, History of Birds, 

 chap. xxv. 



7. Protection of Young. The following will supply heads for observation : con- 

 cealment or inaccessibility of nest, aggressive action of parents, protective devices, e.g. feigning 

 injury. Note individual variations in parents ; also in devotion of male and female respectively. 

 Causes of mortality in young birds. Literature : W. P. Pycraft, History of Birds, chap. xv. 



8. Self-protection (young and adult). The following will supply heads for observa- 

 tion : (1) active defence with feet, wings, beak; (2) escape by flight, running, diving; (3) hiding 

 under cover or water; (4) concealing coloration; (5) menacing acts, such as puffing out 

 plumage, hissing, snapping mandibles, etc. ; (6) warning utterances ; (7) combination for 

 defence ; (8) do birds post sentinels ? (9) self-protection against extremes of weather, floods. 

 At what age does fear develop ? For the question of instinct the young must be studied, 

 possibility of imitation being excluded. 



9. Locomotion. Differences in the locomotion of species ; flight, hopping, walking or 

 running, climbing, swimming. For instinctive locomotion in young birds see Lloyd Morgan's 

 Habit and Instinct, chap. iii. 



10. Social or Solitary Life. (a) Degree of gregariousness (pair, family, flock) at different 

 times of the year shown by different species. 



(6) Solitary life (with respect to other members of the same species) normally occurs 

 outside the breeding season ; only certain British example is the robin. Map of adjacent areas. 

 See vol. i. pp. 430-435 (robin), and 305 (dipper). 



(c) Mutual aid. To what extent are communities of birds more than mere aggregations 

 of individuals, that is, to what extent social organisms ? All instances of mutual aid carefully 

 noted ; also of lack of co-operation. What particular qualities are developed by the social and 

 solitary life respectively? Literature: Lloyd Morgan, Animal Behaviour, pp. 225-234; 

 Kropotkin, Mutual Aid (Heinemann), stimulating but exaggerated, and with fanciful state- 

 ments. Should be read in connection with previously quoted work. Better is Espinas, Les 

 Societes Animales (Bailliere et Cie). 



(d) Origin of the bird community or flock. What causes certain species to unite, others 

 not ? Distinguish between flocks formed temporarily for feeding or migration : and those that 

 are permanent (all year) or seasonal, and note all facts bearing on the formation of these, e.g. 

 flocking of first broods with or without parents, of families, of smaller flocks into large. Lloyd 

 Morgan, Animal Behaviour, pp. 225-234. 



(e) Gregarious roosting. For problems raised see vol. i. pp. 26-28 (crows), 34-38, 44 

 (rook) ; vol. ii. pp. 114-124 (starling). 



(/) Simultaneous flights and concerted movements. Cause of, when no cause for alarm 

 apparent that can explain the simultaneity. Examples : vol. ii. pp. 115-16 (starling), 314 (sand- 

 martin) ; vol. iii. pp. 463-5 (dunlin). 



(g) Commensalism and parasitism. Commensalism is the social relationship between 



