EAZA Hornbill Management and Husbandry Guidelines

M. Kinnaird (Sheppard and Worth, 1997) found that sealing material of great hornbills
Buceros bicornis largely consisted of their high-fiber fecal material (see Section 5.1.4:
Fiber), compared to captive hornbills, which frequently plaster the entrance with sticky,
soft food items. Kinnaird and O’Brien (1997) noted that figs in the plastering matrix of
Sulawesi wrinkled hornbills Aceros cassidix function as limestone gravel in concrete.
Items such as bananas, figs, boiled (not too soft) potatoes, boiled yam, soaked Bird of
Prey diet and minced meat are used in captivity. Mud, pottery clay, riverbank clay and
the hornbills’ own (relatively low fiber) feces have also been mentioned in breeding
reports. Elephant and horse feces, soil, saw dust, straw, peat, insects (cockroaches and
bumblebees) have been worked into sealing mixtures by hornbills, and do provide fiber.
Materials placed in the nest can serve for plastering as well as lining materials (see
Section 6.3.5: nest lining). Each pair may have its own preferences, and offering a variety
of potential plastering materials could stimulate nesting activity. If the nest entrance is
appropriate in form and thickness and sealing material falls out of the opening, other
materials should be offered.
The shape and size of the nest entrance can greatly affect the hornbills’ ability to seal the
nest. The larger the opening the more difficult sealing it is. A square or rectangle nest
opening is more difficult to seal then an essentially diamond or oval shaped opening.
Shape of nest entrances used by four hornbill species in Thailand are shown in Appendix
11.G. A thin material is more difficult than a thick one (minimally 3 cm wall thickness is
recommended). Straight edges are more difficult to seal than uneven edges and smooth
edges more difficult than rough edges (A. Kemp, pers. comm.). Hemp rope has been
attached to the inner edge of the nest opening at some zoos, including Audubon Park Zoo
(Reilly, 1988; Uzee Sigler and Myers, 1992), to provide anchorage when plastering
materials could not adhere to the nest opening. Attaching extra wood around the entrance
to make it thicker has also worked in some cases.
6.3.5 Nest lining
Both males and females bring lining to the nest, and males may continue to do so after
the entrance is sealed. Nest lining can help to control nest humidity, and provides a soft
substrate and a means to sanitize the nest through removal of soiled material. Nest lining
can be adjusted by the female and young to raise or lower the height of the cavity. Some
species prefer a moist lining, such as green leaves and grass, while others prefer dryer
materials, e.g. bark flakes and dry leaves. Some materials may have anti-parasitic and
anti-pathogenic properties, but this must be tested (Kemp, 1995).
Hornbill managers at Audubon Park Zoo have a schedule for changing the nest substrate
a couple of weeks before breeding of a given species is anticipated (Appendix 11.F). The
substrate used at Audubon Park Zoo for all the hornbills is a combination of
approximately equal portions of moist potting soil, wood (pine) shavings and sphagnum
moss. Enough potting soil is added that the mixture holds together fairly well when
compressed in the hand. The lining is thought to be quite important to general health
survival of the chicks.
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