Forage Preferences of Southern Black‐Throated Finch ( Poephila cincta cincta ) in the Desert Uplands Bioregion of Australia

ABSTRACT

Seasonal patterns of resource availability can influence the dietary behaviours of wildlife and how they utilise the landscape. For threatened species, understanding diet preferences and availability and quality of food is also critical for their conservation. This information is important to allow well‐informed decisions for the protection and management of habitat for these species. We investigate the seasonal dietary preferences of the southern subspecies of the endangered black‐throated finch ( Poephila cincta cincta ) in the Desert Uplands bioregion of Queensland over 4 years. We examined their diet composition ( n  = 204 observations) and selection preferences from ground cover surveys within 2 × 1 m plots ( n  = 425). Foraged species availability within the study landscape was quantified from 220 randomly selected vegetation cover plots (1 × 1 m plots × 10) and used to determine Jacobs' selectivity index, a measure of diet selection preference. Spearman's correlation coefficient was tested for the nutritional and physical properties of the seeds of the preferred species against Jacobs' Index to determine factors influencing preferential selection. We identified 46 plant taxa, including 33 grass species, in the diet of black‐throated finch. However, a relatively small subset of these grasses was preferred for consumption due to their higher profitability, reduced handling time and seasonal availability. Digitaria ciliaris , Paspalidium rarum , and Panicum effusum were strongly favoured, especially during the wet season when seeds from these grasses are more available. These preferred species have higher metabolisable energy and crude protein content, and shorter seeds than other grasses that are more abundant in the landscape but are consumed less. Synthesis : These findings highlight the importance of maintaining habitats that support the availability of nutritionally valuable grass species to aid conservation efforts for this threatened species. We also demonstrate the importance of identifying seasonal patterns of dietary preferences in response to availability and nutrition parameters to better manage wildlife across landscapes.