Summary A monitored population of the critically endangered Plains‐wanderer (Pedionomus torquatus) on Victoria's Northern Plains declined by over 90% between 2010 and 2012 following an unusually wet year which led to flooding, excess grass growth and a major change in the structure of native grasslands. The Plains‐wanderer population remained very low on private land during 2013 and 2014 when dry conditions prevailed and domestic stock overgrazed most of its favoured grasslands on red soil. Numbers also remained very low on public reserves despite grassland structure gradually improving there by 2014. In 2015, the population partially recovered in some grasslands protected from overgrazing. Grassland structure is critically important for Plains‐wanderer conservation. The ‘golf ball technique’ proved to be a quick and effective method for measuring grassland structure; it offers a means of accelerating responses to habitat change because it can be easily used by land managers.

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The brown falcon, Falco berigora, is one of Australia's most common and widespread raptors, inhabiting a broad array of habitats and most climatic zones across Australia. We monitored a large, marked population (44-49 pairs) over three annual breeding seasons in southern Victoria. Reproductive parameters such as clutch size and the duration of parental care were constant across years. However, there were marked differences in brood size and the proportion of pairs breeding. Both sexes of falcons were found to have high territory and mate fidelity, with only 10% of members of each sex changing territories during the study. Falcons were flexible in their choice of nest sites, using a variety of tree species and even isolated nest trees. Nest sites and territories were regularly distributed throughout the study area, with the density of the population the highest on record for this species. The diet of the population as a whole was very broad, but each pair predominantly specialised on either lagomorphs, small ground prey, small birds, large birds or reptiles. Individuals that changed territory within the study area also switched their diet according to the predominant land-use within the new territory and thus prey availability. We argue that, at the population level, broad dietary breadth, flexibility in choice of nest site, and a conservative, static breeding strategy allows the species to persist in a broad range of environments, possibly through 'bet-hedging'. At the individual level, changeable dietary specialisation, high territory fidelity, strong year-round territorial defence, confining breeding to years when individual conditions were favourable and adjusting brood sizes when required appear to be the main strategies enabling brown falcons to thrive under a variety of conditions.

Our understanding of the habitat needs of grassland fauna is often incomplete because of their cryptic behaviour. This presents a barrier to identifying important habitat attributes, whether these change at different spatial scales, and how this informs management decisions. Here, we use a critically endangered bird, the Plainswanderer (Pedionomus torquatus, Pedionomidae), as an exemplar of the challenge of managing grasslands for cryptic species. Until now, almost all ecological knowledge of Plains-wanderers has come from the detection of nocturnally roosting individuals and habitat assessments at fine-scales that indicate open swards are preferred habitat. We GPS-tracked 13 adult Plains-wanderers to better understand diurnal habitat utilization in native grasslands of south-eastern Australia. Using these data, we assessed whether Plains-wanderers select for different habitat attributes during the day and night, and whether this varied according to spatial scale. At the fine-scale (< 1 ha), daytime foraging occurred in denser swards than those of nocturnal roosting sites. At the patch-scale (1-50 ha), Plains-wanderers selected for denser vegetation, with higher grass and lichen cover, whilst avoiding areas where structure was impacted by a high exotic plant cover. Plains-wanderers did not select habitat based on grassland type at the landscape-scale (>100 ha). We demonstrate that Plains-wanderers require grasslands with both open and denser swards to support foraging and roosting. In doing so, we address the biases associated with habitat assessments based on roost-only locations and extend known habitat associations critical to the successful management of the species. Our findings highlight that a precautionary approach to the classification of habitat requirements is warranted when uncertainty around habitat use of cryptic grassland fauna exists.