Pygmy Nuthatch Migration: Permanent Resident; reduction of 90% based on transect and nesting surveys 4 birds /km versus 0.4  It is a Ponderosa Pine Obligate Up to 80% of Winter diet consists of Ponderosa Pine seeds  Norris, R. A. 1958. Comparative biosystematics and life history of the nuthatches Sitta pygmaea and Sitta pusilla. Univ. Calif. Publ. Zool. 56: 119–300.   Cavity nester (primarily in ponderosa pine but will also nest in Douglas Fir) Shifts diet to insects during breeding season Gregarious and social all year Family flocks consist of parents and helpers (average 5-6 individuals ) Aggregate roosting especially in winter (15 or more birds roosting together is not uncommon and up to 100 roost together)  Energy saving mechanism