Revieivs 29


being of a brilliant metallic copper colour with purple and violet


reflections, while the under-surface from the chest downwards is pure


white. The typical form Pholidauges leucogaster occurs in West as well


as in North-east Africa, while P. I. verreauxi, which differs in having


white on the outer tail-feathers, is confined to South Africa, and a third


form, P. sharpei, occurs in East Africa.


Sexing Birds. — I think there is a great deal in the theory put


forward by Miss Knobel as to the distance apart of the pelvic bones


in the sexes of birds. It is well known amongst poultry-keepers that


these bones are considerably farther apart in a bird that is in laying


condition than in one that is not laying, in fact, hens and pullets are


constantly examined to ascertain if they are laying or not. At the


Zoological Gardens a few hens are kept as foster-mothers for young


Pheasants, etc., and during last year a fair number of young Silkies


were reared for this purpose ; there are three cockerels and a number of


pullets, and I have examined these. I find that in the cocks the two


bones are barely half an inch apart, this dimension being exceeded


by all of the pullets. Some of the latter have commenced to lay, and


these have the pelvic bones more than an inch apart ; in one case


the distance was an inch and three-qaurters, while in those birds that


had not commenced to lay the distance was about three-quarters of


an inch.


D. S.-S.



REVIEWS

The Auk. Vol. XXXVIII, No. 1. 1921.

This number of the organ of the American Ornithologists' Union

opens with an interesting account of the habits of the Diekcissel (Spiza

awiericana), otherwise popularly known as the " Little Meadowlark ",

or Black-throated Bunting, of the prairies of Illinois, by Dr. Alfred 0.

Gross, This first instalmant deals with the geographical range of the

species, its distribution in Illinois and its migrations, its sexual and

seasonal coloration, measurements, etc., its general behaviour and song.

The paper is illustrated with four photographic plates, three pf which

show nests in situ with eggs or nestlings.



