190 BRITISH BIRDS. [vol. viii. 



observers notice exactly where the old birds collect 

 their food, or what food they bring ? How manj- see 

 exactly how many young finally leave the box ? And 

 even if the young are counted, who tries to follow up 

 the family when it has left the nest ? Blue-Tits do 

 not travel a great distance, and it should not be very 

 difficult to keep them under observation. Which trees 

 ■do they most frequent after leaving the nest, and what 

 food do they get ? How long do the old continue to 

 feed the young ? How long is there between the time 

 when the first of the young is seen to find food for itself 

 and the time when one of the parents is seen feeding 

 the last of the young for the last time ? In what way 

 do the birds find the food ? Is the food of such a nature 

 that there is an advantage in the flock moving about 

 together ; for example, do the insects (or whatever it 

 may be) occur in large numbers locally, so that when 

 one bird finds one insect all the others can be sure of 

 finding a number in the same tree or on the same 

 branch ? How soon does the family unite with other 

 families of the same species, or with other kinds of 

 Tits, or with Goldcrests or Willow- Wrens ? Does such 

 a union take place by chance, and do the families unite 

 and divide up again during the course of the day ? 

 Do the old birds remain with their family for a long 

 time, even till the next spring, or do the young of several 

 famihes go about together, and do the old birds form 

 separate parties ? Is it possible to see whether the 

 pairs remain together all the time tiU the next spring ? 

 Do many family -parties roost in one place, and what 

 places do they choose for the roost ? Supposing that 

 the parties remain together for a number of months, 

 when do they begin to split up into pairs ? Do the 

 old birds begin pairing and nesting earher in the spring 

 than the young ? 



These questions are easy to ask but not to answer. 

 Yet the answer depends, not on a deep scientific know- 

 ledge of the structure and classification of birds, nor 



