6534 Birds. 



river systems ; * and 3rd, the distribution of water and land ; as well as 

 by temperature and the all-important consideration of a sufficient 

 supply of food, which are at present thought to be almost the sole 

 cause. It will thus be seen how desirable it becomes, with a view to 

 future generalization, that additional pains should be taken to register 

 exactly all occurrences of our rarest birds. At least the month, and 

 far better the day, are well worth recording where possible, instead of 

 the vague notices of "lately " or " within the last few months," which 

 cannot serve a purpose like the present. 



Another point upon w r hich some further information would be very 

 acceptable is with respect to the periods at which the old and young 

 birds move. I believe it is very generally thought that the old males 

 precede the females and young by an interval of several days ; but 

 that this rule does not hold quite absolutely I have had good proof by 

 finding female redstarts and blackcaps, as well as males, among the 

 first flights ; and if the females are less noticed they are also more 

 retiring in their habits. I have certainly shot both male and female 

 godwits from the same flock in May. 



And if in most cases " the females and young w are later in ad- 

 vancing to their breeding haunts, is it of males only or of both sexes 

 that are composed those small detachments of old birds only, which, at 

 least in the case of the dunlin, are the earliest to return in autumn? How 

 comes it, too, that when the birds of this family lay but four eggs, so 

 far smaller a proportion is found among the September flocks, unless 

 it be supposed that most of the parent birds have hastened on by 

 themselves at an earlier period. Yet sometimes at least the female is 

 found accompanying the young brood. 



May we find some good observers who will try to solve a part of 

 these most interesting problems ! And even if no precise rule can be 

 fixed, why need we despair of discovering something more than is 

 known at present of the general law r s ? though Natural History, 

 and especially migration, be not reducible to mathematical exact- 

 ness. 



A. G. More. 



Bembridge, Isle of Wight, 

 April 16, 1859. 



* It is believed that the course of rivers and the neighbourhood of the coast are 

 both followed in preference by migratory birds. 



