80
THE ESSEX NATURALIST
hours spent on the Norfolk coast and on our well loved Essex saltings
with Curlews and Dunlin, Redshanks and Brent Geese for company?
I was sorry to find Mr, Day labelling the Starling as "the English
Mocking Bird" as would anyone be who had woken in the West Indian
dawn to the song of the American Mocking Bird. But I enjoyed the
perhaps unintentional humour in this paragraph about the Pheasant
(p. 64): "The cock pheasant pays court to his chosen lady like an
eighteenth-century gallant and, true to form and period, keeps and loves
not one but many. He is a roue most flagrant. But no hen can resist him.
Which is the way of most roues. He can fly at from thirty-five to forty
miles an hour".
Both these books are illustrated in colour with the pleasant series of
pictures of fishes and birds originally published by Messrs. Brooke Bond
Tea Ltd.
A. C. W.
Land Invertebrates. By J. L. Cloudsley-Thompson and John Sankey.
156 pages. 16/-.
Introduction to the Study of Animal Populations. By H. G. Andrewartha.
281 pages. 30/-. Both published by Methuen.
Both of these books are of interest and use to the naturalist but offer a
different approach to the study of animals. The first is of the "traditional"
type and is a handbook for the identification of groups of animals, other
than insects, which hitherto have been neglected by writers of popular
handbooks. The authors, both of whom are experienced field naturalists,
give short descriptions and keys to Flatworms and Roundworms, Earth-
worms, Woodlice and other lesser known arthropods, Slugs and Snails.
With the possible exception of the Flatworms and Roundworms clear
diagrams of "identification parts" and whole animals are given. A
notable omission is in the absence of information on how to collect and/or
observe these rather unobtrusive animals. However, as this is fairly well
covered in a previous book by Sankey the keen naturalist would not be
at a loss.
The second book is of quite different content and really is concerned
with what can be done after animals are identified.
The author has attempted to provide an introduction to quantitative
ecology and while many naturalists will shy away from the small amount
of mathematics required, the serious ecologist must begin to treat his
work in this manner. After a rather lengthy introduction, the author
discusses the theory of population density, dispersal, components of en-
vironment, and then describes in detail some twenty experiments and
techniques. These include the measurement of density, dispersal rate,
measurement of preferences for food and moisture and the study of inter-
and infra-specific effects of competition. Some of the experiments are
for use in the field, some for the laboratory and the remainder for the
garden.
Both of these books are worthy of purchase by the serious naturalist
and are really complementary.
W. M. Y.