24 NORWEGIAN JER-FALCON. 
Mr. Wolley remarks that it would be convenient to call this bird 
Falco Gyr-falco Norcegicus, and in the first edition of this work I 
adopted this name. It has been suggested, however, that as this bird 
is the only true " Jer Falcon," any addition to it draws an impression 
that there is another somewhere else. I have therefore omitted the 
affix in this addition. 
In captivity it differs a good deal from the white and Icelandic birds. 
It is obstinate, revengeful, and sometimes attacks Falcons of any 
species, or darts upon its comrade instead of its game. 
With regard to the specific difference between the Gyr-falco and F. 
Islandicus M. Schlegel observes: — "When young, the Gyr-Falcon 
agrees in colour in every respect with the young of the Iceland bird, 
and the distribution of colours has the same individual varieties in 
both. The feet are, when young, of a dirty olive green, approaching 
to yellow distinctly on the plates covering the toes. The cere or eyelids 
are generally rather brighter than the feet. 
The arrangement of colours of the adult Gyr-Falcon is very agree- 
able, and resembles that of the full-grown Peregrine, with the excep- 
tion of the nape, which in the former is ornamented with some 
white spots; head and region of the ears slate-coloured. The mous- 
tache is less marked, and not so dark; the spots of the inferior parts 
are more decidedly transverse; but the feet are of a greenish colour, 
and the tints in general offer in their shades more or less sensible 
modifications. In other respects the Gyr-Falcon is quite different from 
the Peregrine; the tail is longer, toes shorter, and there are other 
characters proper to the division to which it belongs, which must pre- 
vent the two birds ever being mistaken for each other. 
The Gyr-Falcon in its perfect plumage, has the feet of a bright 
olive green, dirty, rather pale, and approachiug to yellow very visibly 
upon the plates of the toes; the cere and eyelids greenish yellow; 
beak bluish, colour of horn, passing into black towards the tip, and 
yellow towards the base. Upper parts and sides of head, posterior 
or lateral parts of the neck bluish grey, black, or slate-colour: this 
tint is rather deeper towards the centre of each feather. On each 
side of the nape is a kind of incomplete collar formed by some rows 
of whitish feathers, each ornamented with a longitudinal blackish 
spot. All the feathers of the upper surface of the wings and second- 
aries are the colour of dark slate, approaching to brown: but this 
tint is broken by the black quill shafts, as well as by the borders 
and spots of bluish grey with which these feathers are ornamented. 
These markings, constantly of a transverse form, are larger and more 
numerous upon the greater wing coverts and secondaries, where they 
