A constantly active little bird (8), Krueper's nuthatch is usually found foraging among smaller branches and cones at the tops of conifer trees (2) (3). The male and female will often forage together, peering and pecking at the trunk, branches and cones in search of food (8). During the summer breeding season, Krueper's nuthatch feeds mainly on invertebrates (2) (3), particularly beetles, moths and butterflies (9). It will occasionally catch prey in the air (3) (8). Seeds form a large part of the diet over autumn and winter (2) (3). To extract seeds from a cone, Krueper's nuthatch will insert its bill between the scales to pull out the seeds, after which the seeds are taken to bark crevices and hammered open (2).
Krueper's nuthatch is territorial, particularly during the breeding season (8). It will vigorously defend its territory against intruders by engaging in ‘song-duels’ with its opponents, often perching in an upright posture, quivering its tail and puffing out the feathers on its breast as part of its display (2).
Breeding begins in March or April, depending on the location (2), and the nest of Krueper's nuthatch is usually placed in a hole in a tree, up to 24 metres above the ground. This species may excavate its own hole in a dead trunk or branch, although it will frequently use existing cavities that have been hollowed out by woodpeckers (2) (3) (7) (8) (9). The nest is constructed mainly by the female, out of bark chips, rotten wood and cone scales, and is lined with moss, fibres, hair, wool, fur and feathers (2) (3).
The female Krueper's nuthatch lays the eggs from mid-April to early May, with individuals living close to the coast typically laying their eggs several weeks earlier than those living at higher altitudes (3). The clutch, which usually consists of 5 to 7 creamy white eggs with rusty or purplish spots, is incubated solely by the female until the eggs hatch after 14 to 17 days (2) (3). After hatching, the chicks remain in the nest until they fledge at 16 to 19 days, during which time both adults provide food for the young (2) (3) (8).