Shelter and a square meal: factors determining honeyeater sightings in the wheatbelt of southwest Western Australia

Abstract

Honeyeaters are the major vertebrate pollinators in Australia and the most common guild of birds in southwest Western Australia. In the wheatbelt of WA, 13 of 20 honeyeater species have demonstrated significant decline over the last century; only two species have increased in abundance and/or range. We analysed nine years of Birds Australia records to determine spatial links between honeyeater sightings and datasets for presence of flowering plants, vegetation complexity and native vegetation extent for 10x10 km grid cells over the wheatbelt. Numbers of honeyeater records were positively correlated with the presence of flowering plant species known. For the wheatbelt, numbers of bird records were correlated with the extent of clearing, with higher incidence in areas that have a greater area of remnant native vegetation. The extent of native vegetation was also significantly linked with honeyeater species richness, the greatest diversity of honeyeaters being found in the northern and southeastern wheatbelt. These landscape-scale findings provide quantitative support for localised observations of the abundance of individual honeyeater species: species that have declined over time demonstrated positive correlations with native vegetation extent in the present study, those that have increased in abundance and/or range demonstrated negative correlations in the present study (perhaps reflecting their ability to use degraded habitats). Significant positive spatial correlations with the distribution of nectar-bearing flowering plant species were evident for species recorded as largely nectarivorous by other authors. Such landscape analyses offer the potential to identify regions important for the conservation and management of this avian guild