The effect of bill structure on seed preference and handling time in granivorous birds was
determined for a long, slender dove bill, a conical finch bill, and a hooked parrot bill using
diamond doves (Geopelia cuneata), Java sparrows (Padda oryzivora) and Fisher’s lovebirds
(Agapornis fischeri). Four seed species were used during trials: white millet (Panicum
miliaceum), red manna (P. maximum), canary seed (Phalaris canariensis) and Japanese millet
(Echinochloa frumentacea). Diamond doves handled all seed species significantly faster than
sparrows and lovebirds, as they swallow seeds whole. Java sparrows and Fischer’s lovebirds
husked seeds prior to ingestion; lovebirds took significantly longer than Java sparrows in
handling all seed species. Seed characteristics, size and shape affected handling time with
reference to bill structure. Diamond doves took significantly longer to handle elongate seeds
while Java sparrows handled round seeds slowly and Fischer’s lovebirds required similar
handling times for all seed species. Java sparrows and Fischer’s lovebirds selected greater
proportions of the same seed species, suggesting that birds which husk seeds prefer similar
seed species. Seeds were not selected according to nutritional intake rate. Japanese millet was
the preferred seed species of Fischer’s lovebirds and Java sparrows, but provided few calories
and little protein per unit time. Seed selection was influenced by bill structure, as seeds were
selected, amongst others, according to handling time, and handling time was dependent on bill
structure.
Key words: seed selection, bill structure, granivorous birds.