THE NATURALIST IN NIDDERDALE. 407 
House, in the flat country of the Vale of Mowbray (110 feet). 
These birds are very plentiful in Norway, where they breed in the 
summer, as I have observed in 1870 and 1871. The Hooded 
Crow is a noticeable bird, and has attracted my attention when 
quite two miles off. It has far greater power of wing than a 
Rook. Rooks begin to build in February. They rob old nests 
to build the new, and apparently wage war upon each other’s 
colonies, as they both bring twigs to and carry twigs away from 
the same rookery. Rooks begin to take long flights at least as 
early as September, when they fly to the salt marshes by the sea. 
They are seen during the summer high up on the moors, often 
when there are no other birds visible. The Jackdaw is a bird of 
the low country, but the Magpie goes up the dales and gills, only 
stopping short of the moors. 
‘“* Pica loquax varias concinnat guiture voces, 
Scurrili strepitu quidquid et audit ait.” 
The Jay also keeps to comparatively low country; it occurs 
in some of the large “falls,” or “hangers,” in Airedale, as in 
Calverley Wood, at 225 feet, and in large woods throughout the 
- district. 
The Nuthatch is rare; I have seen it only once, in the deep 
wooded gorge of Hackfall (500 feet). The Wryneck and the Tree 
Creeper, common in the South of England, I have never seen 
anywhere in the district. In December, 1868 or 1869, Mr. Ormerod 
shot a Lesser Spotted Woodpecker in Bak’stone Gill, near Loft- 
house; but it is a rare bird here. 
The Cuckoo ranges from sea-level up to the high moors, where 
they ascend as high as Ring Ouzels or Titlarks are found to make 
nests for them. In spring, up to 1200 feet or higher, there are 
few places on the moors in which it is possible to be out of hearing 
of a Cuckoo. Cuckoos begin to go in little flocks of six or seven 
by the end of July or beginning of August. On August 2nd, 1867, 
I saw in Surrey a flock of six Cuckoos in the plumage of the first 
year, and later in the day a second group of four, also in the 
plumage of the first year. They arrive in April in flights of twenty 
or thirty birds. The Cuckoo has a long, plaintive, somewhat 
wailing note, very soft and musical. It has also a rattling note, 
not altogether unlike that of a Landrail. Cuckoos vary much in 
colour, some young birds being dark ash-coloured, or cinereous ; 
