INDIVIDUALITY OF BIRDS. 25 



bird's model basket in the flags ; the snug little caves 

 of the marsh-wrens ; the hermitage-huts of the sly 

 wagtails and ground-warblers ; the stout fortresses 

 of sociable swallows ! v 



Moreover, there is much that is highly interesting 

 which remains to be learned about nests, and which 

 can only be known by paying close attention to these 

 most artistic masterpieces of animal art. "We want 

 to know by what sort of skill the many nests are 

 woven together, that we find it so hard even to dis- 

 entangle ; we want to know how long they are in 

 being built ; whether there is any particular choice in 

 respect to location ; whether, it be a rule, as is sup- 

 posed, that the female bird is the architect to the 

 exclusion of her mate's efforts, further than his sup- 

 plying a part of the materials. Many such points 

 remain to be cleared up. Then there is the question 

 of variation and its extent in the architecture of the 

 same species in different quarters of its ranging area. 

 How far is this carried, and how many varieties can 

 be recorded from a single district, where the same 

 list of materials is open to all the birds equally? 

 Variation 'shows individual opinion or taste among 

 the builders as to the suitability of this and that sort 

 of timber or furniture for their dwellings, and ob- 

 servations upon it thus increase our acquaintance 



