Brown-headed Nuthatch

Research Update

The Brown‑headed Nuthatch has declined throughout its range as a result of habitat loss from human development and habitat degradation through fire suppression and logging. Nuthatches require mature, open pinewoods and seem to thrive in areas that support the endangered Red-cockaded Woodpecker.  Brown‑headed Nuthatches have been designated a species of management concern in several evaluations, and the Bahamian subspecies is thought to be highly imperiled.

Red arrow points to one of the lowest nests we have observed.

In 2001, we began color-marking nuthatches on Tall Timbers to gather better information on ecology and management needs.  We also wanted to understand more about the cooperative breeding behavior that was first described in 1958.  Adult helpers defend territories, build nests, and care for young, but several fundamental questions were unknown before our study began.  To date we have banded 242 adults and 410 nestlings, and some of our key findings include:

Nests are low and constructed in snags in the final stages of decay (Fig).  Nuthatches select the softest piece of wood they think will last the 33+ days it takes to complete a nesting cycle. 

Adults are sedentary and long-lived. Our oldest individual, a female, was captured as an adult in 2002 and has used the same area during each year of study.  She also has nested in the same snag for the past 4 years. 

Distances between nearest neighbors average about 200 m and suggest a density of about 1 territory per 7 acres.

Female nuthatches killed by rat snakes.

Annual survival is lower for females (ca. 65%) than for males (ca. 72%), and this likely influences cooperative breeding because it results in fewer available mates.  We find dead females in nesting cavities and snakes that have killed females while they brood young and incubate eggs (Fig).

Our largest cooperative breeding group contained 5 adults, but most (>70%) cooperative breeding groups contain 3 adults.  The frequency of cooperative breeding groups ranges from 10 to 32% annually.

Observed dispersal spans short distances and is larger for females than males (Fig).  Males breeding for the first time often establish territories within 300 m of the territories held by their parents (i.e., generally the nearest neighboring nest to the natal territory), and this behavior often produces small neighborhoods that consist of closely related individuals.  For example, four neighboring nests monitored in 2005 consisted of a father and 3 of his sons born in previous years.  The father also was assisted by a son born in 2004.

Observed dispersal (in meters) for female (F)
and male (M) nuthatches on Tall Timbers.

Current projects include:

• Long-term demographic monitoring on Tall Timbers
• An assessment of genetic variation in Florida (with Dr. Rebeca Kimball, UF
• Fine-scale spatial genetic structure (with Sarah Haas and Dr. Rebecca Kimball)
• Influence of early season prescribed burning on productivity and survival
• Provisioning rates of breeding adults and helpers (with Lora Loke, UGA)

Publications

Cox, J., and G. Slater.  2007.  Social breeding in the Brown‑headed Nuthatch.  The Wilson Journal of Ornithology 119:1‑8.