Vol. XXIV. 
1924 
Reviews. 
79 
Not so with the ducks, for it is quite certain that among most 
of our ( i.e ., American) common ducks, the females and young 
start first and go farther, while the males come later, and these 
males even stay in a more northerly winter area.” And, like 
the Golden Plover, some Ducks do not return by the same route. 
Members of the duck tribe in flight travel at various estimated 
heights, up to 5,000 feet altitude, while the speed is about forty 
to fifty miles an hour, and probably never exceeds sixty miles. 
‘Aeroplanes travelling at not more than 75 miles an hour have 
managed to pick up and kill ducks over the rice-fields of 
California. ” 
Ducks “display” at almost any time of the year, except when 
t he birds are in full moult, and the Doctor adds, with an un¬ 
conscious touch of humour, “Ducks that are definitely paired 
practically cease to display.” The majority of fresh-water and 
diving ducks nest on the ground, while nearly all the tropical 
species nest in trees, not necessarily in hollow limbs, but fre¬ 
quently in deserted stick-made nests of other birds. All line 
their nests with down, except the Tree Ducks. Clutches of eggs 
vary according to the species from two to fourteen* in number. 
'The typical term of incubation, in accordance with the natural 
law of periodicity, is twenty-eight days, but the term varies in 
some species from twenty-four to thirty-four days. Few males 
assist in incubation, among the fresh waters, and amongst the 
diving ducks, none. 
The process of moults—two annually—although mystifying, 
is not without interest. Soon after the females commence to 
incubate, the males retire and begin to change to the “eclipse” 
plumage. “During the eclipse, which is a much plainer and 
less-differentiated dress that remains in its full development 
for only about three or four weeks, the primary wing-feathers, 
as well as the tail-feathers, are moulted, and the bird becomes 
flightless.” This flightless stage reminds one of Black Swan 
“flappers.” De-sexing ducks reacts on their plumage phases. 
Dr. Phillips is sceptical about ducks carrying their young, in 
their bills, from nesting trees to the ground, or water, as the 
case may be. Now is the opportunity for country observers to 
send in their testimony of any such instances witnessed. How¬ 
ever, Dr. Phillips sounds a warning note that must be heeded. 
“Among the vanishing species,” he states, are “several Australian 
ducks,” including the Auckland Islands Mergauser, or Flightless 
Duck, the only flightless anatine bird in the world. It is up to 
Australians to endeavour to save this remarkable “missing link.” 
A further notice will appear in The Emu when the other 
volumes of this fine work have been received — a criticism more 
particularly dealing with the history of those species of Ducks, 
which arc Australian. 
