262 
ALI.En’s naturalist’s LIIiRARY. 
short hiss, \vhen bullying some other bird or fighting amongst 
lemselves, hut, he adds “ I have heard occasionally on the 
coast of North Wales at night a somewhat Wigeondike whistle 
that emanated, as I believe, from ‘Sand-Geese ’ on the wing.” 
Nest. —Composed principally of the bird’s own down, with a 
^w leaves occasionally, as mentioned above by Mr. Robert 
Read. In some parts of Denmark the peasants make artificial 
burrows for the birds, and systematically rob the nest, as many 
as thirty eggs having been taken from one burrow in a single 
season. ^ 
Eggs.— From seven to twelve in number, but sometimes as 
many as sixteen have been found. They are dull creamy- 
white, with ^very little gloss. Axis 2 -45-2 -6 inches ; diam. 
IS ashy-grey, with silvery white ends! 
and with a few white feathers intermingled. 
THE RUDDY SHELD-DUCKS. GENUS CASARCA. 
Ciuarca, Bp. Comp. List B. Eur. & N. Amer. p. 56 (1838). 
Type, C. casarca (L.). 
The members of the genus Casarca, according to the conclu- 
sionsof Count Salvadori, differ from the typical Sheld-Ducks 
(Jadc/rna) in the following characters The bill does not 
widen towards the tip, and is no broader at the tip than it is at 
the base; the culmen is almost straight; the lamellEe are 
equally developed along the inner edge of the upper mandible 
and the lamellm on the edge of the lower mandible proiect 
outwardly; the bill and feet are dark, and the sexes generallv 
differ in colour. ^ 
Four species of the genus Casarca are known, C. casarca 
C. cana from South Africa, C. variegata from New Zealand' 
and C. tadornoides from South Australia and Tasmania. In 
the Ruddy Sheld-Duck, where the sexes are alike, there has as 
yet been no proof of any change of plumage in summer sucii 
as occurs in most species of ducks. The post-nuptial pluma-e 
IS probably emphasised by the loss of the black collar fn 
die three other species, however, where the sexes are different 
in colour, the male doubtless undergoes a chamm, as INIr. 
lll.iauw has noticed a double moult in C. tadornoides. 
