Partitioning of nectar sources in an Australian honeyeater community

Abstract

Abstract Feeding by honeyeaters was found to maintain nectar at low levels at three sites studied on Kangaroo Island in May‐June 1978. The productivity of nectar at a site and position in a dominance hierarchy appeared to determine which bird species used each site. Correa was the main nectar source in the poorest area and produced 0.05 kJ m −2 per day. The small eastern spinebill was the most abundant honeyeater. The purple‐gaped honeyeater also occurred but fed mostly on honeydew. The medium sized New Holland honeyeater was common and territorial in the second area, where Banksia marginata and B. ornata inflorescences and Adenanthos flowers produced 0.7 kJ m −2 of nectar per day. Spinebills and crescent honeyeaters also visited flowers and were sometimes chased by New Holland honeyeaters. The richest site was a flowering Eucalyptus cosmophylla tree (5.1 kJ m −2 of nectar per day). A red wattlebird, the largest honeyeater, held a territory in part of this tree and chased other honeyeaters from the territory. New Holland, crescent and purple‐gaped honeyeaters fed on flowers in other parts of the tree. The spinebill was absent. We conclude that nectar was partitioned along a spectrum of rich to poor sources. Larger more aggressive species used and sometimes defended the richest sources while the smaller birds used the poorer sources.