Treecreepers are small, cryptic woodland birds that spiral up tree trunks in search of invertebrates. Their welfare is linked to mature tree availability and bark invertebrate diversity.
Treecreeper welfare in cold weather is constrained by reduced invertebrate availability in bark crevices at low temperatures. Unlike other insectivores, treecreepers cannot easily switch to alternative food sources. Supplementary feeding with fat smeared into bark crevices can provide welfare support during cold spells. Retention of mature trees with deeply furrowed bark — oak, sweet chestnut, Scots pine — provides the structural complexity that supports both invertebrate diversity and nest sites.