Introduction
Hornbills, Bucerotidae, are very large and conspicuous
birds throughout the old world tropics. The tropical forests
of south and southeast Asia include mixed deciduous,
moist evergreen, dry evergreen, hill evergreen and tropical
rain forests that support an unusual diversity of hornbill
species. Since hornbills are secondary cavity nesters,
unable to excavate their own nest cavities, their reproduction
is limited by the availability of suitable cavities.
Additionally, being omnivorous birds, they depend for
much of their food on fruit resources and these are affected
greatly by forest habitat destruction. Because of their rigid
requirements for breeding sites, hornbills are threatened by
human activities, such as forest destruction and hunting,
which pose more important immediate threats to hornbill
populations than previously realized. On the other hand,
the appearance and nesting habits of hornbills are very
attractive to visitors and potentially are important drivers
for ecotourism.