Use of Sugar-water Feeders to Supplement Energy Availability to Honeyeaters for Experimental Tests

Summary

I report observations of honeyeaters at sugar-water feeders conducted over two years in heathland near Sydney. Eight to 14 sugar-water feeders were distributed over a 4 ha patch of heath, and placed away from existing territories to minimise the chance of feeders being monopolised by a few birds. All common species of honeyeaters used feeders, and feeders were used extensively during all months except May-July (when nectar from Banksia ericifolia was abundant) and November-January (when there were few honeyeaters on the heath). Incidence of aggression at feeders was low, and most birds that were excluded could feed as soon as the aggressor finished using the feeder. Feeders were occasionally defended by large honeyeaters (Little Wattlebirds, Noisy Friarbirds and Red Wattlebirds) but these species were relatively uncommon. Feeders were never defended by New Holland or White-cheeked Honeyeaters, which were the most common species and defended breeding territories on the heath. Consequently, the majority of feeders were always freely accessible, so that they provided easy access to energy similar to that provided by rich and abundant nectar sources such as Banksia ericifolia. I conclude that feeders can be used to test whether correlations between nectar abundance and honeyeater abundance, behaviour and breeding are caused by responses to changes in energy availability.