THE HUMMINGBIRD COMMUNITY OF A LOWLAND AMAZONIAN RAIN-FOREST

Between October 1987 and September 1989, the British Ornithologists' U nion Colombia Expedition recorded 16 species of hummingbird at Matamat a in the Amacayacu National Park, Amazonas, Colombia, Most of these sp ecies were resident breeders at the study site although two appeared t o be local migrants. Six species of hermit hummingbirds (subfamily Pha ethornithinae) occurred at Matamata; although very similar in general morphology and behaviour, they showed different preferences for habita t, food plants and foraging technique, Hermits were predominant in the forest, but in areas of secondary vegetation and along riverine borde rs,''typical'' hummingbirds (subfamily Trochilinae) wore more common. The study site consisted of terra firme and varzea forest and an area of riverine secondary vegetation and contained around 60 species of fl owering plants visited by hummingbirds. In contrast with most groups o f organisms, hummingbirds and hummingbird-pollinated plants had simila r species diversity in primary forest and secondary habitats, The over all abundance of hummingbirds and flowers was significantly higher in areas of riverine secondary growth. The hummingbird community at Matam ata is remarkably species rich when compared with study sites elsewher e in North and South America, However, random null model comparisons a mong Amazonian hummingbird communities reveal that they share many cha racteristics in their structure and show a high degree of species over lap.