130 
The Endurance of Birds. 
pleasing, sweet singing hybrids have been produced, but I do 
not know of any instance where the hybrids huv'e bred and 
reared young, though such closely related species should pro- 
duce fertile hybrids. 
The hen is not easily distinguished from her mate, but 
she is usually a wee bit smaller and slightly paler in colour than 
her mate, but these distinctions are intinitesimal. Song is the 
best test and usually infallible, though 1 have come across hens 
(had one suchj which sang almost as strongly as the males. 
Grken Singing-finch (S. icterus). Some years ago I 
wrote an article on the species and I am including it here as it 
covers all that need be said thereupon. 
This beautiful Southern and Western African bird greatly 
resembles our English Siskin in colour, size, and activity, but 
is more slimly built, and is fully as active and entertaining 
among the branches as our native Tits. A description would 
be superfluous — it being well known — therefore will simply say, 
for the benefit of any unacquainted with this charming Serin, 
that is a bright yellow bird, variegated with olive green and 
lined with black. 
They are very attractive and pleasing, both in colour and 
deportment, readily become tame, but arc quarrelsome %n a 
mixed collection put up for breeding; with a mixed assortment 
of Finches kept simply for show and not for breeding, a single 
specimen may be kept without much risk proz'iding there is 
plenty of space- They are quite hardy, in spite of what some 
writers have stated " that the least frost would be fatal "; mine 
have been out doors all the year round for three years, in a 
small portable aviary, which is but little more than a large box 
cage, with waterproof gable top; they are never covered up at 
night, not in the severest weather, and they show by their de- 
meanour in the midst of them, that our winter frosts wet and 
fog, do not inconv^enience them in the least. 
There is no apparent sexual difference, the hen being 
perhaps a shade smaller and a trifle duller in colour, but this 
distinction would only hold good, when the birds were of the 
same age. For instance, an old hen would be as large and as 
brilliant as a young cock, in spite of this there is but little diffi- 
