EAZA Hornbill Management and Husbandry Guidelines

6.3.7 Inspection door and observation devices
While the editors of these guidelines believe that breeding hornbills should be left alone
as much as possible, there are certainly times when nest inspections or some form of
intervention are desirable. It is highly recommended that an inspection door be fashioned
at the backside of the nest box so that the inspection door can be opened to clean the nest,
to remove eggs or young and to observe the female and her brood as appropriate. The
door should be positioned at the height of the nest entrance, assuming that the entrance is
not too high (see section 6.3.3: Dimensions of the nest entrance). The door should be
fairly large (approximately 15 cm X 20 cm) so that even older chicks can be removed if
necessary. The door should shut perfectly to avoid droughts, incoming light and opening
by the female. Cuts to make the door can be angled inward to ensure that light will not
come through the opening. Females may pound on the door and unless very well
fastened, the door may open (e.g. Meyers, in press). For this reason Khin et al. (1997)
recommended using a sliding door.
Some hornbill managers (e.g. at Audubon Park Zoo and San Diego Zoo) that are quite
successful with hornbills do routinely check hornbill nests (M. Mace and M. Meyers,
pers. comms.). Nests at Audubon Park Zoo are checked every couple of days until egg
laying is completed and then less frequently but regularly once hatching is expected. Nest
inspections are made once or twice a week once chicks have hatched. One person
distracts the female with a stick at the nest entrance while another person looks through
the inspection door. The inspection door entrance is shrouded with a blanket, and a
flashlight used to spot the eggs (M. Meyers, pers. comm).
Presence of chick(s) inside the nest box can be observed with an investigation tube with a
45° angle (Mace, pers. comm.), as described below in Figure 5, or by holding a
stethoscope to the wall to hear chick sounds (Euing, 1995). A microphone mounted in the
nest out of reach from the hornbills can enable hornbill managers and possibly visitors to
monitor vocalizations and other sounds made within the nest. The speakers should be a
good distance from the male so that he does not become confused.
A video surveillance system provides a non-invasive monitoring method that yields much
information. If nest images are also viewable by visitors, the system also provides a
wonderful educational tool. Lieras (1983) provided a description of the video
arrangement used to monitor a Luzon tarictic hornbill Penelopides manillae nest at San
Diego Zoo and of observations made. Smith (2002) found monitoring equipment
surprising inexpensive: the entire surveillance system to monitor a pair of Von der
Decken’s hornbills Tockus deckeni at Oklahoma City Zoo, including two cameras, a
monitor and all the necessary cables was US$ 90. See Section 6.3.8: Camera monitoring
of nests for a description of video monitoring experiences at Chester Zoo.
52