Associated Species: Other species that may use habitat in a similar way and/or respond similarly to threats, management, and conservation activities include Flammulated Owl, Olive-sided Flycatcher, Violet-green Swallow, Pygmy Nuthatch, and Western Tanager.

Distribution: Grace's Warblers breed from southwest Colorado and southern Utah, south through central Arizona, western New Mexico, and into north-central Mexico. Wintering areas extend from northern Mexico to Central America.

Habitat Requirements: Grace's Warblers inhabit open ponderosa pine forests with pines 5 m (16 ft) tall, especially stands with a Gambel oak understory.

Ecology: Birds arrive in Colorado in early May and lay eggs in late May and early June; the young fledge by late June and early July. Nearly four decades after Webster (1961) declared this "one of the least known of North American parulids," little new information has been published about its ecology.

Management Issues and Conservation Recommendations: Threats to Grace's Warblers include the loss of mature ponderosa pines due to timber harvest, and the closing of ponderosa stands by dense young trees, a result of fire suppression. Restore ponderosa pine forests to presettlement conditions of large trees, in clusters, with an open understory of grasses.

Status and Reasons for Concern: Grace's Warblers have a high conservation need locally and throughout their range. They are not adequately monitored by the BBS within Physiographic Area 62, and sample sizes are too small to permit analysis of trends. Continent-wide results do not show a statistically significant annual rate of change (P = 0.42; n = 32) between 1966 and 1996, although the results for the same period in New Mexico approach statistical significance (-6.5%; P = 0.12; n = 14 routes). This species is monitored by MCB with point transects.

Biological Objective: Maintain or increase the species' distribution and abundance based on results of the MCB or other monitoring programs.

Selected References: Andrews and Righter 1992, Kingery 1998, Webster 1961.