An Experiment on Germination of Ligustrum and Paederia Seesd collected from Bird Droppings

Abstract

An experiment on germination of the seeds collected from bird droppings was carried out from February 3 to March 25, 1978. The species of the seeds were Ligustrum japonicum and Paederia scandens, both of which are widely distributed and are abundant in urbanized areas in Tokyo. The seeds of these plants are found quite commonly in the droppings of fruit-eating birds, such as Brown-eared Bulbuls, Hypsipetes amaurotis. The material of the experiment consisted of the following 3 groups; (A) seeds obtained from bird droppings, (B) seeds with the pericarp removed artificially, and (C) seeds with the pericarp intact.The results of the experiment are given in Figs. 1-2. The seeds of A group, which passed through a bird's digestive tract, showed a tendency to germinate earlier and have a higher germination rate than the others (B and C groups). In the case of L. japonicum seeds, A and B groups showed 100% rate of germination, This suggests that a germination-inhibiting material included in the pericarp was removed in the course of digestion in the digestive tract of birds. But in the case of P. scandens seeds, B group showed a lower germination rate than A group. Consequently not only the removal of the germination-inhibiting material but some other factors, such as physical impact on the seeds by the bird bill, may also be involved.Recently the population of Brown-eared Bulbul is increasing in urbanized areas. They eat fruits of L. japonicum and P. scandens, digest part of the pericarp, and drop the seeds with their droppongs. Such seeds have a higher percentage of germination. Thus it apears that fruit-eating birds such as the bulbuls is taking part in vegetation changes in the urbanized areas.