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Oregon Vesper Sparrow

Oregon Vesper Sparrow (Pooecetes gramineus affinis)

Habitat: Prairie and Oak Savannah
Habitat Attribute: Low to moderate statured herbaceous vegetation and scattered woody cover

Population Objectives (Ecoregions)
Target Densities in Suitable Habitat:

Puget Lowlands:

  • By 2030, increase the current estimated population of 270 birds by ≥69.3% (5.4% annual exponential growth rate) to ≥457 birds, with ≥229 birds in ≥8 subpopulations, and another ≥229 birds elsewhere throughout the ecoregion.

Willamette Valley:

  • By 2030, increase the current estimated population of 1,000 birds by ≥31.9% (2.8% annual exponential growth rate) to ≥1,319 birds, with ≥660 birds in ≥21 subpopulations, and another ≥660 birds elsewhere throughout the ecoregion.

Klamath Mountains:

  • By 2030, increase the current estimated population of 200 birds by ≥90.5% (6.7% annual exponential growth rate) to 381 birds, with ≥192 birds in ≥8 subpopulations, and another ≥192 birds elsewhere throughout the ecoregion.

Habitat Objectives (Ecoregions)
Puget Lowlands:

  • By 2030, maintain ≥8 suitable habitat areas as described below that include ≤ 1,204 ha (2,975 ac) with ≥70% habitat suitability/patch.

Willamette Valley:

  • By 2030, maintain ≥21 suitable habitat areas as described below that include ≤1,477 ha (3,650 ac) with ≥70% habitat suitability/patch.

Klamath Mountains (Rogue Basin):

  • By 2030, maintain ≥8 suitable habitat areas as described below that include ≤361 ha (891 ac) with ≥70% habitat suitability/patch.

Population and Habitat Objectives (Subregions)
Puget Lowlands: Size, Number, and Distribution of Subpopulations and Habitat Areas by 2030:

  •  ≥1 large subpopulations (i.e., ≥25 pairs) in <337 ha (833 ac)/subpopulation
  • ≥2 medium subpopulations (i.e., 15-25 pairs) in <193 ha (476 ac)/subpopulation
  • ≥6 small subpopulations (i.e., 5-15 pairs) in <96 ha (238 ac)/subpopulation
  • ≥3 of the small habitat areas, ≥1 of the medium habitat areas, and ≥1 of the large habitat areas should have ≥90% of the area in secure conservation status (i.e., ownership or easements) and being managed in ways compatible with suitable habitat

Willamette Valley: Size, Number, and Distribution of Subpopulations and Habitat Areas by 2030:

  •  ≥3 large subpopulations (i.e., ≥25 pairs) in <142 ha (350 ac)/subpopulation
  • ≥6 medium subpopulations (i.e., 15-25 pairs) in <81 ha (200 ac)/subpopulation
  • ≥12 small subpopulations (i.e., 5-15 pairs) in <41 ha (100 ac)/subpopulation
  • ≥6 of the small habitat areas, ≥4 of the medium habitat areas, and ≥2 of the large habitat areas should have ≥90% of the area in secure conservation status (i.e., ownership or easements) and being managed in ways compatible with suitable habitat

Klamath Mountains: Size, Number, and Distribution of Subpopulations and Habitat Areas by 2030:

  • ≥1 large subpopulation (i.e., ≥25 pairs) in <98 ha (243 ac)/subpopulation (Rogue)
  •  ≥2 medium subpopulations (i.e., 15-25 pairs) in <66 ha (162 ac)/subpopulation (Rogue)
  • ≥4 small subpopulations (i.e., 5-15 pairs) in <31 ha (81 ac)/subpopulation (Rogue)
  • ≥10 of the small habitat areas, ≥5 of the medium habitat areas, and ≥3 of the large habitat areas should have ≥90% of the area in secure conservation status (i.e., ownership or easements) and being managed in ways compatible with suitable habitat

All Ecoregions:

  • ≤10% of the subpopulation habitat area should be hostile habitat (i.e., urban, residential, high-density rural)

Population Objectives (Sites)
Target Densities in Suitable Habitat:
Puget Lowlands:

  • South: >0.02 birds/ha (>0.01 birds/ac)

Willamette Valley:

  • North: >0.01 birds/ha (>0.004 birds/ac)
  • South: >0.03 birds/ha (>0.01 birds/ac)

Klamath Mountains:

  • Rogue: >0.04 birds/ha (>0.01 birds/ac)

Habitat Objectives (Sites)
Upland prairie, savannah, or appropriate agricultural types (i.e., light to moderately grazed pasture, fallow fields, Christmas tree farms) in areas >50 ha (20 ac) in the following conditions:

  •  tree cover <10%
  • shrub cover <15% and scattered (i.e., not contiguous as in fence rows, field buffers, etc.)
  • bare ground 5-15% and scattered (i.e., not in one or a few large spots)
  • herbaceous cover that is structurally and compositionally diverse with:
    • mean graminoid height of 15-46 cm (6-18 in), including <20% <15 cm (6 in) tall, and <20% >46 cm (18 in) tall
    • forb cover >15%

Rockwell, S. M., J. L. Stephens, and B. Altman. 2022. Population and habitat objectives for landbirds in prairie, oak, and riparian habitats of western Oregon and Washington. Version 2.0. Prepared for Oregon-Washington Partners in Flight, Pacific Birds Habitat Joint Venture, Bureau of Land Management, and U.S. Forest Service. Klamath Bird Observatory, Ashland, OR, and American Bird Conservancy, Corvallis, OR.