266 BRITISH BIRDS. [vol.xv. 



inconvenience to either the sitting bird or the young to 

 account for such building precautions. Many theories might 

 be advanced as an explanation but after examining over thirty 

 nests, three only of which have been constructed with the 

 canopy as described above, I am unable to offer any satis- 

 factory reason for what I think must be an unusual habit. 



In these parts various situations are chosen for nesting 

 purposes. I have known the nest situated in an open patch 

 in a garden shrubbery not many yards from the front door 

 of a house. At other times the spot chosen is miles away 

 from any habitation on the desolate moor, but never of 

 course in a treeless part. The majority of nests which I have 

 found have been built in short heather, but I have noticed 

 that the birds not infrequently prefer a patch or strip of rough 

 grass should such a one occur on or bordering the heath land. 

 It so happens sometimes that a nest built openly amongst 

 dead bracken stems, although clearty exposed to view at the 

 time the bird begins to sit, becomes entirely sheltered and quite 

 invisible before the young are ready to leave, owing to the 

 luxuriant growth of new green bracken having sprung up 

 in the meantime. In such circumstances it is, of course, 

 impossible to watch the birds to the nest. 



The rmmber of eggs is usually four, yet sets of three only 

 are fairl3/ frequent with first clutches. A five clutch, as far 

 as my experience goes, only occurs in later nests and not very 

 often then, for I have only known that number three times 

 and it is somewhat remarkable that in each case all five 

 hatched, seeing that at least one addled egg is very usual 

 even with clutches of three, and I have known a case where 

 only one egg of a clutch of three hatched, the remaining two 

 showing no sign of fertility. This state of affairs is perhaps 

 attributable to the weather, which is often treacherous with 

 severe frosts during the first incubation period (March-April) 

 but more favourable to a complete hatch later on. 



The eggs vary greatly in size, shape, colour and character 

 of markings, but all in the clutch are generally, though not 

 always, true to type. 



Each pair of birds seems persistent in rearing at least two 

 broods, but many nests meet with disaster, and nestlings are 

 often destroyed by Crows, Magpies, Jays or Stoats. In one 

 case a Little Owl was probably the culprit, in another a 

 Hobby {Falco s. subbittco) which I had twice noticed passing 

 dangerously close on his evening " beat," I believe discovered 

 and took a whole family, for they disappeared with remarkable 

 suddenness. In 1920 a nest containing eggs upon which the bird 



