lyS ECOLOGY AND LIFE HISTORY OF THE COMMON FROG 



was written to encourage entomologists to examine these records, 

 much as I am now doing for ecologists at large, has a number of 

 comments and criticisms. Some of these seem to be based on a 

 projected use of limited scope, but others are interesting. I do not 

 think, however, that Williams stresses the most important point, 

 which is that the information that can be extracted far exceeds a mere 

 research into a date of a natural event. Because we keep our records of 

 weather and many other events classified according to date, we have, 

 once we know the date of an event, an almost urdimited amount of 

 information at our disposal. To consider phenology as a mere matter 

 of dates is like considering an index as something to do with the 

 alphabet. For example, take the date of arrival of the cuckoo. Not 

 being an ornithologist, I have no idea how closely this date is correlated 

 with the date at which it is first heard calling, but I should guess that 

 the correlation coefficient must be high. It should therefore be 

 possible to use an immense amount of records to study the factors 

 affecting its arrival. There is little doubt that weather records, classified 

 by dates, could be obtained from France, the Mediterranean, and from 

 Africa, and included in a scheme as in Chapter 8. To point the matter 

 by an absurd example, it would even be possible to include atmospheric 

 pollution in New York, or the height of the tide at Singapore, if the 

 investigator thought that these might show a significant effect. All 

 this could be done now, without Hfting a finger to get specially 

 collected data. 



There seem to be two main ways in which this could be done. The 

 methods of Chapter 8 could be used by anyone prepared for about two 

 years work on the problem for one animal, after preliminary work had 

 established the main factors involved. It would be unwise to assume 

 the correctness of any accepted hypotheses not verified by adequate 

 statistical analysis, so that there might be a considerable amount of 

 abortive exploration. The alternative is one that I have discussed with 

 Dr. J. F. D. Frazer. Once the records, both phenological and meteoro- 

 logical, were collected in suitable form, electronic computation could 

 immensely shorten the labour required to deal with every animal 

 separately, for, with all the means, totals, variances and covariances, 

 equations such as that in Chapter 8 could be built up rapidly. The 

 result of the apphcation of either method would be an unprecedented 

 amount of information on the external factors affecting salient events 

 in the lives of animals and plants, taken straight from the field, and 



