Already a subscriber? Sign in Don't have a subscription? Subscribe Now
Pygmy Nuthatch
Sitta pygmaea
Order
PASSERIFORMES
– Family
SITTIDAE
Authors: Kingery, Hugh E., and Cameron K. Ghalambor

Welcome to the Birds of North America Online!

Welcome to BNA Online, the leading source of life history information for North American breeding birds. This free, courtesy preview is just the first of 14 articles that provide detailed life history information including Distribution, Migration, Habitat, Food Habits, Sounds, Behavior and Breeding. Written by acknowledged experts on each species, there is also a comprehensive bibliography of published research on the species.

A subscription is needed to access the remaining articles for this and any other species. Subscription rates start as low as $5 USD for 30 days of complete access to the resource. To subscribe, please visit the Cornell Lab of Ornithology E-Store.

If you are already a current subscriber, you will need to sign in with your login information to access BNA normally.

Subscriptions are available for as little as $5 for 30 days of full access! If you would like to subscribe to BNA Online, just visit the Cornell Lab of Ornithology E-Store.

Introduction

Adult Pygmy Nuthatch
Figure 1. Distribution of the Pygmy Nuthatch.

A noisy, chattering, social species, the Pygmy Nuthatch lives in long-needled pine forests—in the United States, principally ponderosa pines (Pinus ponderosa). Frenetic movements—head first, up tree, down tree, along branches, right-side up and upside down—accompanied by constant chatter, convey the busyness and nervous activity of this gregarious bird as it searches for food.

Because it uses cavities for roosting and for breeding, the Pygmy Nuthatch reaches its highest densities in mature pine forests little affected by logging, firewood collection, and snag removal. It feeds mainly on weevils and leaf and bark beetles (but also eats pine seeds), and is 1 of the few cooperatively breeding passerines in North America and 1 of the world’s 2 cooperatively breeding nuthatches. A third of the breeding pairs have 1–3 male helpers, usually progeny or other relatives. Helpers feed incubating females, nestlings, and fledglings and participate in defense of the nest site. Breeding units and their offspring form the nucleus of winter flocks. During the nonbreeding season, family groups flock with other Pygmy Nuthatch families that range over a foraging territory. They also join with other flocking birds of the conifer forests. Pygmy Nuthatches generally dominate these species in the social hierarchy and in volubility.

The Pygmy Nuthatch roosts in cavities, which it selects depending on season and weather. It picks roosts based on insulation and ventilation provided by roost cavities and relies on hypothermia to survive cold winter nights. Although a few other North American birds are capable of controlled hypothermia, only the Pygmy Nuthatch links hypothermia with protected roost sites and communalism. Pairs roost together; juveniles roost with parents, and collectives of several flocks roost together. Stacks of 6, 8, and 10 birds, and more, roost together in formations of squares, oblongs, triangles, diamonds, wedges, and tiers. Two articles report more than 150 individuals roosting in 1 tree (Knorr 1957, Sydeman and Güntert 1983).

Robert A. Norris (1958) conducted the most extensive research on Pygmy Nuthatches. His thorough monograph covers all aspects of the biology of this species and compares it to its sister species, the Brown-headed Nuthatch (Sitta pusilla). Russ Balda and associates have addressed many aspects of Pygmy Nuthatch biology, such as cooperative breeding, roosting behavior, physiology, flocking behavior and hierarchy, feeding strategy, and habitat use (Balda 1967, 1969, 1975; Szaro and Balda 1979, 1982; Balda et al. 1983; Hay 1983; Brawn 1985, 1987, 1988; Brawn and Balda 1988a, 1988b; Güntert et al. 1988; Löhrl 1988; Sydeman et al. 1988; Sydeman 1989, 1991; Szaro et al. 1990; Ghalambor 1998; Ghalambor and Martin 1998; Martin and Ghalambor 1999).