Pygmy Nuthatch Superspecies #38 Sitta pygmaea Vigors       Field Guide IDs: NG-332; G-234; PW-pl 45; AW-pl 389; AM(II)-338 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy F I: 15-16 DAYS ALTRICIAL SNAG 6 feet - 60 feet MF+ 6-8 (4-9) MONOG (COOP) F: 20-22 DAYS MF+ CONIFER .....SEEDS HOVER & .......GLEAN HAWKS BREEDING: Pine forests (esp ponderosa, yellow, Jeffrey), pinon-juniper woodland. DISPLAYS: ? NEST: Often excavated in pine, also in post, occasionally uses deserted woodpecker hole; bed of plant down, bark shreds, hair, feathers. Both sexes help with nest construction. EGGS: White, sparsely flecked with reddish-browns. 0.6" (15mm). DIET: Includes spiders. Young fed insects and spiders. CONSERVATION: Winter resident. NOTES: Long-term pair bond. Breeding units consist of 2-5 birds: helpers are unmated males, mostly yearling offspring or siblings of the pair; assist in nest building, maintenance, feeding female on nest, and feeding nestlings and fledglings. Territories maintained all year, defense limited to vicinity of nest cavity. Female broods. Pairs with helpers fledge more young than do unaided pairs. Cache coniferous seeds. Western equivalent, ecologically, of Brown-headed Nuthatch. In winter, groups of 4-15 forge as a flock and roost communally in nest cavities; occasionally form loose mixed-species flocks with warblers, titmice, chickadees. STANFORD. NOTES: ESSAYS: Birds, DNA and Evolutionary Convergence; Tool Using; Superspecies; Communal Roosting; Hoarding Food; Cooperative Breeding; Mixed-Species Flocking. REFERENCES: Norris, 1958; Sydeman et al., 1988.