452 CONFERENCE OF DELEGATES 



Do the parent sparrows learn anything from their first experience so that 

 times are speeded up, or do the seasons or the monotony that is bred of 

 repetition slow down the speed of development in the later clutches ? 



That kind of inquiry could be extended almost indefinitely, because it 

 is applicable to all our common birds ; it would answer unsolved questions ; 

 and best of all it would afford an outlet and a training for that inquisitiveness 

 and desire for acquisition of knowledge which lies at the heart of every 

 naturalist. To those of you who still may think that there is little to be 

 learned about British birds (and we may regard them as the most studied 

 of all the components of the fauna) I would commend the reading of a short 

 article on ' Our Present Knowledge of the Breeding Biology of Birds,' con- 

 tributed by the Rev. F. C. R. Jourdain a few years ago to British Birds 

 (vol. 24, 1930, p. 138). It is because of the unfolded possibilities in a 

 nestful of eggs, that I am mainly against the taking of eggs. Every egg taken 

 destroys an opportunity of recording the development of the young, and 

 that is what we wish to learn about, life and its development. The old 

 Latin tag put it neatly : omne vivum ex ovo, ' every living thing develops from 

 an egg ' — but nothing ever developed from an empty egg-shell. 



From another angle of observation the songs of birds afford many oppor- 

 tunities of discovery. I have a correspondent who settled for his own 

 district, in the North of England, the simple question, ' How long does a 

 skylark sing ? ' With a stop-watch and patience to listen to over 500 songs, 

 he found the average length to be just 2 -22 .minutes. But there are many 

 things to watch for : Mr. Rollin found, for example, that the larks which 

 sang longest all kept together in the same field. No one suggests that larks 

 make a selected chorus, but why do the best singers all keep together ? — 

 the suggestion is that perhaps the older birds tend to flock together, and that 

 from age and practice these may be the more efficient singers. We do not 

 know much about such things ; every accumulation of observations is of 

 value, provided the observations are carried out on a scientific plan. 



The life-histories of birds, or of insects, or of mammals or any other 

 creatures, the influence of the weather and the seasons upon development 

 and upon the plant and animal population of a circumscribed area, the 

 changes wrought upon plant and animal groups by the interference of man, 

 these and many other problems ofifer themselves as subjects proper for the 

 direct attack of natural history. 



Simple Experimental Zoology. 



But there is another sort of attack, somewhat less direct and straight- 

 forward in its method, which is open to you and which will appeal to those 

 who wish to exercise a little ingenuity in unravelling the ways of animals, 

 the method of experimental zoology. I know it is a common notion that 

 experimental zoology, a fashionable development of our science at the 

 moment, is bound up with elaborate apparatus, elaborate dissections and 

 transplantations of tissue, and so on ; but it has its simpler side, and I have 

 the impression that, where simplicity is possible, the less elaborate the 

 interference with an animal may be, the more likely is the reaction to be the 

 natural reaction. 



The sort of experiment I have in mind, and any one of you could carry 

 out such an experiment, is such as Charles Darwin's test for the intelligence 

 of an earthworm. An earthworm has a very tiny brain — that was a real step 

 in the evolution of life upon the earth, for before worms existed there were 

 no brains at all ; and Darwin wished to know if that simple brain endowed 

 a worm with any glimmering of intelligence. Worms have a habit of pulling 



