Pygmy Nuthatches are found along the Pacific coast from Baja up into southern British Columbia, and range as far south as central Mexico. Pygmy Nuthatches can be found as far east as central Montana and Colorado. They also live in patches throughout the mountainous regions of Mexico (Bent, 1948).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: RESIDENT: southern interior British Columbia, northern Idaho, western Montana, central Wyoming and southwstern South Dakota south to northern Baja California, southern Nevada, central and southeastern Arizona, central New Mexico, extreme western Texas and extreme western Oklahoma, south in mountains to cental Mexico (AOU 1983). To elevations of 3000 m.

Male Pygmy Nuthatches have a grayish-brown crown on their heads; they also have a black stripe through their eyes, and a white line over their eyes. Their back and central tail feathers are bluish gray, and they have reddish brown underbellies. Pygmy Nuthatches have white spots on their outer tail feathers and have dark brown bills and feet. Female Pygmy Nuthatches are very similar to the males, differing in that the females have a bluish gray crown along with underbodies that are usually paler then the underbodies of males (Hoffman, 1927).

Range mass: 9.3 to 11 g.

Range length: 9 to 11 cm.

Other Physical Features: endothermic ; bilateral symmetry

Length: 11 cm

Weight: 11 grams

• Terrestrial

Pygmy Nuthatches prefer to make their homes in long-needle pine forests, especially in Ponderosa, Monterey, and Jeffrey pines. They are found in their highest density in old-growth forests that are undisturbed and contain numerous dead pines. Pygmy Nuthatches live in valleys, and they are also found in mountainous areas all the way up to the tree line, as long as there is an abundance of old-growth pine trees (Kingery and Ghalambor, 2001).

Range elevation: 4250 (high) m.

Habitat Regions: temperate

Terrestrial Biomes: forest ; mountains

Comments: Pine forest and woodland, especially ponderosa pine, less frequently pinyon-juniper (AOU 1983). At night may roost in groups in tree cavities. For the Pacific Northwest, U.S. Forest Service et al. (1993) recommended maintaining adequate numbers (around 0.6/acre) of large snags (over 15-20 inches dbh, if possible) and green tree replacements for future snags (can be left in groups to reduce blowdown), in stands of ponderosa pine. Breeding pair digs a hole in dead wood, or uses an abandoned woodpecker hole. Nest hole is usually 2.5-18 m above ground. May be limited by nest site availability. In northern Arizona, breeding density was increased from 4-19 breeding pairs per 40 ha to 9-30 pairs after nest boxes were added (Brawn and Balda 1988). See Mitchell (1988) for specifications for the construction and placement of nest boxes.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

During the breeding season Pygmy Nuthatches have a diet which consists of 60-85% insects, such as beetles, wasps, ants, and caterpillars. The other portion of their diet includes seeds from pine trees and other plant materials. Pygmy Nuthatches use their bills to probe the cracks of trees and peel off bark to expose the insects that are inside the tree. They also search inside the crevices of pine cones on trees and on the ground for insects. Pygmy Nuthatches feed in flocks, especially during the non-breeding season. This appears to increase the ability of the flock members to find a food source. The winter diet of this bird comprises of seeds or insects, depending on the birds location and the food available (Kingery and Ghalambor, 2001).

Animal Foods: insects

Plant Foods: seeds, grains, and nuts

Primary Diet: carnivore (Insectivore )

Comments: Feeds on insects (wasps, ants, beetles, moths, grasshoppers, etc); also eats spiders and pine seeds. Forages on outer branches and twigs as well as along tree trunks.

Pygmy Nuthatches prefer to nest in old-growth pine forests and they eat pine tree seeds and insects. So, they are responsible for some seed dispersal. Since the majority of Pygmy Nuthatches' diet is insects, they are also responsible for influencing the population of insects in their territory (Kingery and Ghalambor, 2001).

Ecosystem Impact: disperses seeds

Pygmy Nuthatches have many adaptations to help them avoid predators. This species of nuthatch sometimes feeds in flocks, which helps it to look for predators and confuse them if they attack. If a predator attacks a flock of Pygmy Nuthatches all the birds in the flock scatter at the same time, and this sometimes confuses the predator long enough for all or most of the Pygmy Nuthatches to fly to a safe location.

When solitary Pygmy Nuthatches spot a predator they position themselves on the opposite side of a tree or branch from the predator to block the advance of the predator.

When squirrels try to invade nests that contain eggs or juveniles, female Pygmy Nuthatches perch at the entrance of their nest, spread their wings, and sway back and forth slowly in a rhythmic movement. Pygmy Nuthatches have also been seen mobbing hawks or other larger birds that may invade their area (Kingery and Ghalambor, 2001).

Known Predators:

• sharp-shinned hawks (Accipiter striatus)
• Cooper's hawks (Accipiter cooperii)
• northern pygmy-owls (Blaucidium gnoma)
• chipmunks (Tamias)
• red squirrels (Tamiasciurus hudsonicus)
• gopher snakes (Pituophis melanoleucus)

Often found in association with yellow-rumped warbler, plain titmouse, or mountain chickadee. Social throughout year. Travels in small family groups after nesting season. Family groups form larger loose flocks in fall and winter. Winter groups average 5-15 individuals; forage as a flock and roost communally within group territory (Sydeman et al. 1988).

ThPygmy Nuthatches' eggs are 15.76 mm in length and 12.21 mm in breadth. Young Pygmy Nuthatches are capable of reproduction at 1 year of age, though some males may become helpers and not reproduce for another year (Kingery and Ghalambor, 2001).

The lifespan of Pygmy Nuthatches was determined by recapturing birds that were banded. The maximum recorded lifespan was 8 years 2 months (Kingery and Ghalambor, 2001).

Typical lifespan

Status: wild: 1 to 6 years.

Pygmy Nuthatches appear to be monogamous and form pair bonds that last through the entire year. Male Pygmy Nuthatches court females by bringing them food before mating has taken place. The males also continue to feed the females after mating, during nest building, egg-laying, and through the incubation process. During the nest building period of the courtship, which takes 3-6 weeks, males and females work together to build the nest. Pygmy Nuthatches can build their own nests but prefer to use nests and other holes that have been made previously by other organisms (Kingery and Ghalambor, 2001).

Mating System: monogamous ; cooperative breeder

Female Pygmy Nuthatches initiates copulation; females perch next to the males on a horizontal branch and face the males with their bills open. Then the females make high pitched calls and hold their tails stiffly away from their bodies to signal to the males that they are ready to mate. Female Pygmy Nuthatches then shake their wings and begin a swinging motion that is common to many nuthatch species. This swing motion is similar to trembling and prompts male Pygmy Nuthatches to sit behind the females and begin the same trembling-swinging motion. The males then mount the females and sometimes peck at the back of the female's head. Copulation lasts less than 5 seconds, then both will fly away (Kingery and Ghalambor, 2001).

Breeding season: April to August

Range eggs per season: 5 to 9.

Range time to hatching: 12 to 17 days.

Range fledging age: 19 to 21 days.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous

Average eggs per season: 7.

Female Pygmy Nuthatches start laying their eggs in the early morning and continue throughout the day. The eggs of Pygmy Nuthatches are white and speckled with chestnut-red or purplish brown spots. The females do not begin incubating the eggs until all of the eggs have been laid, but the females do cover the eggs with nesting materials until the entire clutch is laid. Male Pygmy Nuthatches bring the females food and nesting material during the incubation process. Pygmy Nuthatches also engage in cooperative breeding, with 1 to several brood helpers (Sydeman, 1989). The helpers are usually male yearlings from the previous year and will help for about 1 year. The helpers feed the females and the young Pygmy Nuthatches when they hatch. Once the young hatch the parents take the egg shells and fly them away from the nest (Kingery and Ghalambor, 2001).

Parental Investment: altricial ; male parental care ; female parental care

Clutch size is 4-9 (usually 6-8). Incubation, by female, lasts 15.5-16 days. Nestlings are altricial. Young leave nest at 22 days (Terres 1980). Cooperative breeding has been documented in California and Arizona; breeding units consisted of 2-5 birds; helpers (mostly yearlings, and offspring or siblings of the birds they aided) were found at about 30% of all nests in northern Arizona; nests with helpers sometimes more productive than those without helpers (Sydeman et al. 1988).

Pygmy Nuthatches need old-growth pines for nesting and collection of food, so they are excellent indicators of the health and age of the pine forests where they are found. Since Pygmy Nuthatches need a specific type of environment to live in they are especially vulnerable to deforestation, by humans and natural causes, which results in significant depletion of old-growth pine trees. Pine forests that have been logged or destroyed because of other reasons have resulted in significant drops in populations of Pygmy Nuthatches (Kingery and Ghalambor, 2001).

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N4 - Apparently Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Needs: See Thomas et al. (1993) for recommendations for the Pacific Northwest.

No significant negative economic aspects were attributed to Pygmy Nuthatches.

No significant economic contributions were attributed to Pygmy Nuthatches, though this species of nuthatch could be a source of insect control.

Comments: Constitutes a superspecies with and has been considered conspecific with Pusilla by some authors (AOU 1983, 1998).