30 FIELD-STUDIES OF RARER BIRDS 



going to the wall ; but the joint- stock problem is 

 not so easily grappled with, and I can think of 

 no other quite similar examples with small birds, 

 though it is well known that certain of the game- 

 birds will lay, not only in one another's nests, but 

 also in some of the duck tribes'). Some of the 

 Waders, too, will occasionally exchange compli- 

 ments in this fashion. Anyway, it must be 

 supposed that the Pied Flycatcher, besides being 

 gentle, is eminently easygoing, not only in that it 

 allows this billeting, but also because it is permitted 

 to go halves with its would-be complete usurper. 



The adult male Pied Flycatcher can be mis- 

 taken for no other species likely to be met with in 

 Britain, but the female and birds of the year, being 

 brown where he is black, may by the tyro in 

 certain lights be confused with the Spotted Fly- 

 catcher. On flight, and especially in a good light, 

 such an error would be inexcusable, owing to the 

 then conspicuous white wing-bar being fully dis- 

 played ; moreover, the habitats of the two species 

 are normally quite at variance. 



The Pied Flycatcher leaves our shores in 

 August and, chiefly, in September, when it often, 

 while thus on migration, occurs in the suburbs of 

 London and elsewhere. I once saw an adult male 

 inland in Cardiganshire on September 29th a 

 really late date for the bird to be still in its summer- 

 quarters, seeing that even on the coast lines a Pied 

 Flycatcher is seldom seen after that day. 



