Effects of bird ingestion on seed germination of two <i>Prunus</i> species with different fruit‐ripening seasons

Abstract

To evaluate the effects of ingestion by birds on seed germination under natural conditions, we carried out germination experiments in the field using seeds of two Prunus species that have different fruit‐ripening seasons. Germination of seeds with the following three treatments was compared: ‘ingested seeds’, seeds excreted after feeding of fruits to birds; ‘extracted seeds’, seeds deliberately extracted from the fruit pulp; and ‘intact fruit’, seeds in untreated intact fruit. Many ingested and extracted seeds of both Prunus species germinated during the first spring, and the difference in germination percentage between ingested and extracted seeds was not significant. Many seeds in intact fruit of Prunus sargentii also germinated during the first spring, but those of Prunus ssiori did not germinate until the second spring. Pulp removal through bird ingestion enabled rapid germination for the autumn‐fruiting P. ssiori , whose fruit pulp was not likely to be decomposed until the first spring. In contrast, the effects of ingestion were not striking for the summer‐fruiting P. sargentii , whose fruit pulp is quickly decomposed.