54 AMID THE HIGH HILLS 
The shafts of the primaries are very strong 
and the wings very long. Gould ^ says, in refer- 
ence to the spine- tailed swift, in a passage which 
is quoted in Seebohm : ^ " The keel or breast bone 
of this species is more than ordinarily deep and 
the pectoral muscles more developed than in any 
of its weight with which I am acquainted." 
Probably the last-mentioned facts largely account 
for its superiority in speed over the Alpine swift. 
In an article entitled " The Twelve Swiftest 
Birds of Australia," ^ in which Mr. E. S. Sovenson 
gives the views of himself and various friends of 
his as to the relative speed of Australian birds, he 
says that after long observation he and they have 
no hesitation in stating that the spine-tailed 
swift is the swiftest Australian bird, and states 
that its speed has been computed at 180 miles 
an hour. 
" Besides its swiftness," he writes, "it is 
almost tireless of wing, being second only in that 
respect to the frigate bird, the bu'd of eternal 
flight. Both have very long wings in relation 
* Handbook to the Birds of Australia, by John Gould, F.R.S. (I860), 
vol. i. p. 104. London. 
» Vol. ii. p. 305, Porter, 6 Tenterden Street, W. ; Dulau & Co., Soho 
Square, W., 1884. 
* Avicultural Magazine, Third Series, vol. x. No. 4, February 1919, 
pp. 73-74. 
