Suitable nesting sites for specialized cavity dependent wildlife are rare in woodlands

•Tree cavities suitable for animals are rare, but only by measuring them directly can their true availability be quantified.•Superb parrots Polytelis swainsonii select cavities with wider entrances, deeper chambers, wider floors and in larger stems than random cavities; - only 0.5% of random cavities meet these requirements.•Ground counts are inaccurate and both underestimated cavity abundance when present, and overestimated when they were absent in trees.•Nest trees had more cavities than random trees, and large, mature trees support more cavities for suitable for animals.•Forest managers should quantify the abundance of suitable cavities; failing to account for their scarcity may result in poor conservation management outcomes.