Land Bird Conservation Plan Colorado  

Introduction
Overview of Colorado
Physiographic Region 36

  • Grasslands
  • Lowland Riparian
  • Shore/Bank
  • Wetlands


  • Physiographic Region 62
    Physiographic Region 87
    Implementation Strategies
    Literature Cited
    Appendices

    Physiographic Region 36: Central Shortgrass Prairie

    Ferruginous Hawk (Buteo regalis)

    Associated Species: Other species that may use habitat in a similar way and/or respond similarly to threats, management, and conservation activities include Swainson's Hawk, American Kestrel, Mourning Dove, Great Horned Owl, and Loggerhead Shrike.

    Distribution: Ferruginous Hawks breed from eastern Washington east to southern Saskatchewan, south to northern Texas, south and west through central New Mexico and central Arizona, and as far west as southeastern Nevada. In Colorado, they are found primarily on the eastern plains, in the grassland and lowland riparian habitat types. Small numbers of these hawks nest in northwestern Colorado and the San Luis Valley.

    Habitat Requirements: Ferruginous Hawks nest in isolated trees or small groves of trees, and on other elevated sites such as rock outcrops, buttes, large shrubs, haystacks, and low cliffs. Nests are situated adjacent to open areas such as grassland or shrubsteppe. These hawks are closely associated with prairie dog colonies, especially in winter.

    Ecology: In Colorado, nesting is initiated as early as mid March, and young fledge during late June and July. Although they do breed in Colorado, Ferruginous Hawks are more common during winter (November to March). Rabbits and hares are the most important prey items by biomass, but prairie dogs and ground squirrels are the most important numerically.

    Management Issues and Conservation Recommendations: Conversion of native grassland to agricultural land has led to population declines. Management of grasslands for grazing is considered compatible with healthy Ferruginous Hawk populations. Encourage public land managers and private landowners to preserve native prairie.

    Control of prey species (ground squirrels and prairie dogs) reduces Ferruginous Hawk populations. Retain populations of the primary prey species at the highest levels compatible with economic uses of the land.

    Ferruginous Hawks are sensitive to disturbance at the nest; activities such as mineral extraction near nests result in lower nest success or abandonment. Restrict activities within 0.8 km (0.5 mi) of active nests.

    Some birds are shot on the breeding and wintering grounds. Encourage strict enforcement of extant game laws that protect this species.

    Some nest trees are in shelterbelts or windbreaks or around abandoned homesteads; as those trees are lost, suitable nest sites become scarcer. Preserve nest trees.

    Status and Reasons for Concern: This species has a high conservation need locally and throughout its range. The Ferruginous Hawk is a USFS Sensitive Species in Region 2, and a CDOW Species of Special Concern. Within Physiographic Area 36, BBS data do not show a statistically significant annual rate of change between 1966 and 1996 (P = 0.69; n = 25 routes). Ferruginous Hawks were present on an average of 34.58% (SE = 3.53) of the BBS routes run in Physiographic Area 36 in Colorado during 1988-1997, at an average abundance of 0.69 (SE = 0.09) individuals per route. The mean number of routes run each year was 29.2 (SE = 2.28). This species is monitored by MCB with tracking transects.

    Biological Objective: Maintain or increase the species' distribution and abundance, based upon results from the BBS and MCB monitoring programs.

    Selected References: Andrews and Righter 1992, Bechard and Schmutz 1995, Harmata 1981, Kingery 1998.


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