THE BIRDS OF AUSTRALIA. 
of the ground. It is unusual to find them flying so low as they are a difficult 
bird to collect under ordinary circumstances. March 30, 1911. Since the 
22nd these birds have been very numerous, but fly very high. April 5. Still 
numerous. April 8. Flocks passed to-day, flying very high. Melville 
Island, Oct. 15, 1911. A few birds passed the camp to-day flying very high, 
and on Nov. 7, 1911, a small flock was seen late in the evening and none were 
afterwards noted.” 
Maclennan’s notes read XVI., p. 221, 1917) : “ King River, Nov. 24, 
1915. Bird seen flying southwards. Dec. 11, 1915. Large flock of Swifts 
passed over camp after the rain, but not sure of identity. Dec. 12, 1915. 
Another flock passed after a heavy shower. Dec. 25, 1915. A number of 
C. pad ficus seen circling high over sandstone ridges.” 
I differentiated a form as Micropus colcloughi, but it is quite uncertain 
whether there are races or species of this group to be recoguised as visitors to 
Australia. There may be races of migratory birds, but it is difficult to determine 
such without good series of locally sexed individuals. Thus, some specimens 
have a greenish gloss, others a bluish gloss ; some have the rump band larger 
than it is in others ; while, sometimes, the shaft stripes on the throat are more 
distinct than at others ; further, the whitish barring to the feathers of the 
under-surface is sometimes prominent, sometimes obsolete. The relationship 
of these phases is not well known, some authorities considering one form 
the adult, some regarding the other as representing the adult plumage. Series 
of Japanese birds of apparently breeding age show both phases, so that 
the matter is still comphcated, as the differences do not appear to be 
sexual. 
The pecuHar case I aUuded to previously is as follows : Harington described 
a subspecies breeding in Burmah as smaller. I examined the bird and found 
that the wing was undoubtedly smaller, but the first primary was longest. 
I suggested the bird was not fully grown, as in the Austraflan adults the second 
primary is longest. Series being procured it was found that these were still 
constantly smaller and, moreover, that the first primary was constantly longer. 
More careful criticism showed that the tail-forking was also sflghtly different, 
and that the subspecies was a vahd one, the differences being probably due to 
its more restricted habitat. Under these circumstances it is possible that the 
two forms discussed above may represent different breeding races, and further 
that a third may occur in west Austraha, as it is improbable that the Japanese 
bird would migrate to that locahty, even if it occurred in eastern Austraha. 
I am afraid the matter of races of this Swift will not be easily solved, as its aUy, 
M. apus and its subspecies and migrations into Africa are still involved in 
much obscurity. 
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