increases have been recorded in response to winter feeding programs in Hooded
Cranes G. monachaand White-napped Cranes G. vipio(Archibald 1978b).
Some species, such as the Trumpeter Swan and cranes may be easy to feed,
because they readily take grain. However, others are more difficult: attempts to
feed wild Echo Parakeets, for example, were surprisingly largely unsuccessful.
After trials with a range of food types offered in various ways, the best that was
achieved was to feed a small number of individuals for a few weeks only (Jones
and Duffy 1993). Captive-reared and released Echo Parakeets proved easier to
feed and took a pelleted diet from hoppers. Young ones reared by released birds
learned to use the hoppers, and thereafter some wild birds also started using the
hopper, presumably through social facilitation. Birds feeding at the hoppers
reared larger broods than the other wild birds, and readily accepted and reared
fostered young. Even lone female parakeets successfully reared young.
Supplementary feeding has proved important in the restoration of the
New Zealand Kakapo Strigops habroptilus. The females fed from hoppers placed
in their home ranges, each female being individually managed. It is hoped that
the provision of supplementary foods will promote and sustain regular breeding
( James et al. 1991; Powlesland et al. 1992), and so far it has increased breeding
frequency and enhanced chick survival (Elliot et al. 2001).
12.3.2Enhancing nest-sites and the provision of nest-boxes
In many bird populations, nest-sites are limiting, especially for species that nest
in tree cavities or on cliff ledges (Newton 1998). In addition many birds have
only poor sites, which do not protect them against predators or adverse weather.
Many species have increased in numbers after the enhancement of existing nest-
sites or creation of new ones, thus demonstrating the limiting effect of nest-sites
on breeding density and success (Newton 1998). Many different artificial nest-
sites have been successful, such as nest ledges and cavities for cliff nesting species,
platforms, and artificial stick nests for tree nesting species, artificial burrows for
terrestrial hole nesters, rafts for wetland birds, and nest-boxes for a whole range
of cavity nesting species.
In the absence of high quality nest cavities, Echo Parakeets and Mauritius
Kestrels tried to nest in sites prone to predation, flooding, or overheating.
Consequently, it became policy to improve nest cavities that were considered
suboptimal. At cavities frequented by kestrels any debris, such as old nest mater-
ial or loose rocks lying on the cavity floor, was replaced with washed gravel. If
necessary, the cavity entrance was modified by placing rocks to provide landing
spots or perches for the kestrels, and in exposed sites rocks were arranged to pro-
vide shade and shelter. Pairs subsequently raised young in many of the modified
274 |Conservation management of endangered birds