Artificial fruiting displays and model fruits were used to measure
fruit handling by birds (figure 1a,b). Displays were wooden dowels
(0.8 cm diameter 45 cm length), each with five holes 4 cm apart
through which galvanized wire (0.7 mm diameter) was threaded.
Model fruits (12 mm diameter) were moulded from non-toxic,
odourless and water-resistant red Plastalina modelling clay and
pressed onto the outer, up-facing ends of wires (10 fruits per display).
Ten displays were attached to separate understorey plants at
breast height and placed greater than 25 m apart within a 100 m
50 m plot. One fruit survey was completed at each site in October,
November and January. Each survey was over 4 days at five sites,
staggered randomly within each month. Artificial displays allow standardization
of the number and arrangement of fruits and placement
within sites. The colour and size of model fruits can be controlled, as
they neither rot nor desiccate, and records of visitation are retained.
The number and type of peck marks could be assigned to the thrush
(figure 1c) and white-eye (figure 1d) because of different bill morphologies
and gape widths (thrush: 13.97+0.52 mm, n ¼ 3;
white-eye: 6.47+0.03 mm, n ¼ 3). The diameter of model fruits
was large relative to the gape widths of these two frugivorous birds
to minimize chances of fruit removal and hence retain feeding
attempts.