Earlier naturalists formed the impression that
bird numbers remained more or less stable through time.
In the years since these words were written, however,
changes have occurred in the landscapes of the British
Isles and in the seas around our coasts, causing bird
populations to fluctuate in an unprecedented
way.
In Ian Newton’s latest New Naturalist
volume, he explores bird populations and why their
numbers vary in the way they do, from year to year or
from place to place. He addresses the various factors
that we know limit bird numbers – food supplies and
other resources, competitors, predators, parasites and
pathogens, and various human impacts.
The
combination of a rapidly expanding human population, a
predominantly utilitarian attitude to land, central
government policy on land use, and increasing
mechanisation have combined to promote more massive
changes in land use – and hence in bird habitats – in
recent decades than at any comparable period previously.
These developments have in turn brought huge changes in
bird populations, as some species dependent on the old
landscapes declined, and others benefiting from the
changes increased. Over the same period, changing public
attitudes to wildlife, protective legislation and a
growing network of nature reserves allowed previously
scarce bird species to recover from past onslaughts,
while climate warming has promoted further
changes.
In this seminal new work, Ian Newton
sets out to explain why different bird species are
distributed in the numbers that they are, and have
changed over the years in the way that they have. He
emphasises the factors that influence bird numbers,
rather than the numbers themselves, thus providing a
much-needed overview which is necessary if we are to
successfully manage bird populations, whether for
conservation reasons, for sustainable hunting or for
crop protection. The continued monitoring of bird
numbers can also alert us to impending environmental
problems. In addition, the regular watching and study of
birds now provides a source of recreation and pleasure
for very large numbers of people, who would find a world
with fewer birds a poorer place.
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