species of Passerine Birds. 55 
The sexes of A. sicula appear to be identical, or nearly so, 
in their plumage^ colouring, and markings, as well as in their 
soft parts and measurements. The young of this species, as 
shown in the accompanying Plate, differs from the adult bird 
in having the greater part of the upper plumage brown, while 
the centre of the crown and the fringes of the scapulars and 
secondaries are whitish ; moreover, on the utiderparts the 
rose^-colour on the flanks and crissura is less pronounced. The 
respective measurements of old and fully-grown young birds 
seem to be the same, except with regard to the tail, which 
is rather longer in the latter, owing perhaps to the absence 
of wear and tear. 
With respect to the distribution of A. sicula in Sicily, 
I may say that it appears to occur only in the more wooded 
inland districts of the island, and at elevations varying 
from 700 to 1500 metres above sea-level, according to the 
time of year and according to the more sheltered or more 
exposed position of the woods frequented. On the sea-coast 
and in the low-lying districts of the island the species appears 
not to be found. The woods frequented by this Titmouse 
vary in character according to their altitude, those lower 
down being mainly composed of deciduous and evergreen oaks 
{Quercus robur, Q. suber, and Q. ilex), chestnuts, and olive- 
trees, while the higher forests are almost exclusively of 
deciduous oak and beech, although the ilex oak also flourishes 
on some of the higher hills. Apparently, however, the 
character of the woods is immaterial to the birds, which 
seem as much at home among the low-growing olive-groves 
as they do among the lofty forest oaks. 
The first examples I obtained of A. sicula were procured at 
the beginning of February in the Bosco di Fienzza, a well- 
wooded inland district, about 750 metres above sea-level, 
lying to the south of Palermo. The woods in this neigh- 
bourhood are composed chiefly of oak, both evergreen and 
deciduous, with a few elms and ash trees, and with a luxuriant 
undergrowth of low-growing plants, mostly of the maquis 
description. Throughout the month of February and the 
early part of March this Titmouse continued to occur 
in the Fienzza woods more or less plentifully, but by 
