Birds of Celebes: Palconidae. 
71 
another'); but, when some of these species by reason of overcrowding, a storm, 
or other cause, are transported to a fresh locality where the conditions of 
existence are changed, the original, fixed coloration becomes disturbed if 
there was originally a useful purpose in it, that purpose is now removed, 
variability has free ^or the time, and the amount of variation is made 
greater and more complicated by the interbreeding of the changing individuals. 
On these grounds the Celebesian Hawk-eagle and Iloney-buzzard should be 
regarded as ancient forms, the variable birds of Borneo, etc. which have not 
yet settled down into a fixed type of plumage of their own, as of more recent 
origin. Leaving out of the discussion Pernis tiveeddalei of Malacca which is only 
known in three or four specimens, the only remaining species of Pernis is oiu’ 
own Pernis apivorus — very variable and therefore, also recent. Spizaetus, 
however, has developed into a number of local species elsewhere than Celebes 
viz. the Indian Kegion, Africa, S. America. Let it be remembered, that Celebes, 
as is shown by some of its mammals as well as by some of its birds, is an 
ancient land, zoologically speaking, and that neither Perms nor Spizaetus (ex- 
cept in the aberrant <S. gurneyi) pass into the still more ancient Australian Re- 
gion, and it will be seen that P. celebensis and <S. lanceolatus have some claim 
to be regarded as the most ancient members of their genera. 
(C) One of the most convincing arguments made use of by Charles Dar- 
win in tracing the descent of domestic Pigeons from the Blue Rock Pigeon 
(Columha livia) was drawn from the occasional reversion, partial or nrarly 
complete, of the former to the plumage of the Blue Rock. If the variable 
Spizaetus limnaetus and Pernis ptilonorhynchus are descended from specimens of 
S. lanceolatus and P. celebensis which have flown across from Celebes to Borneo, 
or the Philippines and further, similar cases of reversion should be found. Now, 
in his Valkvogels Ned. Ind. Schlegel portrays nine specimens of the variable 
Spizaetus limnaetus (called by him S. cirratus) and six of Pernis ptiloiwchynclms 
(here called cristatus: pis. VI- VIII and XXV, XXVI), and among them some faiil^ 
good matches to the two forms of Celebes may be seen. About four specimens 
of a Honey-buzzard called Pernis tiveeddalei, Hume, have been described from 
Malacca and Sumatra; it bears much resemblance to Pernis celebensis, and it seems 
very doubtful if they are more than individual variations of the variable P. 
rhimchus. since that bird lives not only on both sides of, but also in the same 
•, As an exception 
Diet. B. ‘•Solitaire”). Thi 
mucti knocked akout in tig ,,- 
See remarks in Introduction on inlierited ni 
on inlierited mutilations of feathers, etc. 
