NANKEEN KESTREL. 
a comparison of the new species with that of the Eastern bird (which is 
identical with our coast bird) the specific differences will appear such as to 
justify, on sight, the above separation. 
“ I assign the scientific name of Cerchneis unicolor to the new bird, and 
the vernacular name of Western Kestrel.” 
The Director of the Western Australian Museum allowed me to examine 
the bird and have the present plate prepared. Later, receiving specimens from 
the Yalgoo District they proved to be normal and have left no doubt that 
Milligan’s specimen was merely an aberration, and not typical of the form 
inhabiting Yalgoo. 
In the Nov. Zool., Vol. XVIII., p. 253, 1912, with the series before me, 
I ranged the species thus : 
Cerchneis cencJiroides cenchroides (Vigors and Horsfield). 
Queensland, New South Wales, Victoria, Tasmania, South Australia. 
Cerchneis cenchroides milligani Mathews. 
“ Differs from C. c. cenchroides in its less size and darker coloration 
above.” North-west Australia. 
Cerchneis cenchroides unicohr MiUigan. 
“ Although the type is a ‘ sport,’ the name may be used for the 
South-west Australian subspecies.” South-west Australia. 
In my List of the Birds of Australia, p. 113, 1913, I maintained this 
division, adding Northern Territory to the range of C. c. milligani. 
With a good and fairly representative series now available I cannot 
recognise any subspecies. All the differences seen seem to be only individual, 
and every attempt to definitely fix any subspecies has failed. 
North also concluded : “ There is little or no variation in specimens 
obtained in widely separated localities, except that due to age.” 
The examination of the series leads to the conclusion that the plumages 
have not been understood, as I find male and female in every stage' yet 
recorded. I can see four stages. 
First. Heavily spotted plumage : spots black, ground-colour cinnamon- 
brown. 
This plumage is apparently only carried for a very short time, as it is 
comparatively rare in collections. 
Second. Common plumage. Birds breed and it constitutes three- 
fourths of specimens secured. The spots give place to narrow shaft-streaks 
and smaller and fewer arrow-shaped markings on back ; upper tail-coverts 
begin to come blue-grey : striping on under-surface deteriorates. The bars 
on the tail decrease in size from the base. 
291 
