360 PRACTICAL AND SCIENTIFIC ZOOLOGY. 
But if you wish to investigate the species of the next 
family (Falconide), you will be sadly perplexed. It 
will be a great point gained, however, if you know the 
habitat or country of your specimens, since this know- 
ledge will very much abridge your labour. For the 
European species, Temminck’s ‘‘ Manuel” is an autho- 
rity which may be looked upon as almost oracular; while 
for those of Britain, Mr. Selby’s work is quite sufficient. 
The volumes of the prince of Musignano, Wilson, and 
** Northern Zoology,’ must be consulted for those of 
North America; Spix for those of Brazil; while Le 
Vaillant is an oracle upon those of Southern Africa. 
Unluckily, nearly all these are expensive books; so that, 
until their contents are collected and digested into one, 
you will always be in doubt whether a species is new or 
old. Upon the whole, perhaps, the two volumes of the or- 
nithological portion of the ‘‘ Encyclopédie Méthodique,” 
by Vieiliot, will be the best manual you can have; and 
they may be purchased in Paris, or of any of the foreign 
booksellers in London, without the third volume of 
plates, which are not only expensive, but absolute ca- 
ricatures. Birds of prey, when young, have a plumage 
very different from that which they acquire in adult age ; 
and that of the females, as in other birds, is sometimes 
different from the males. It will require a certain de- 
gree of tact (only to be got by experience) to distinguish 
a young from an adult falcon ; but, by examining the 
specimens of these birds in the British or any other 
museum, you will soon get some ideas on this point. 
M. Temminck, who excels all other ornithologists of 
the day in a practical knowledge of this intricate family, 
has figured many of the foreign species in his “ Planches 
Colorées ;” all which are incorporated in the “ Traité 
d’Ornithologie” of Lesson. The species of owls are as 
difficult to determine as the falcons, and you must con- 
sult for them the same authors. 
(445.) Next come the order of Znsessores, or perching 
birds, and this order is larger than all the others put 
together ; hence the groups belonging to it are much 
