Skip booklet index and go to page content

NORTHERN SPOTTED OWL (Strix occidentalis caurina)

Appendix 5

Suitable Spotted Owl Habitat Definitions for British Columbia (from SOMIT 1997)

Habitat TypeSuperior Habitat
(nest, roost, forage, and dispersal)
Moderate Habitat
(roost, forage, and dispersal)

Wetter ecosystems: Maritime Coastal Western Hemlock and Mountain Hemlock Biogeoclimatic Zones

Natural Disturbances: Rare to infrequent stand-initiating events.

Suitable habitat characteristics
  • Three or more canopy layers, multi-species canopy dominated by large (>75 cm dbh) overstorey trees (typically 37–185 stems/ha)
  • Moderate to high (60–80%) canopy closure.
  • Five or more large (>50 cm dbh) trees/ha with various deformities (e.g., large cavities, broken tops, dwarf mistletoe infections).
  • Five or more large (>75 cm dbh) snags/ha.
  • Accumulations (>268 m3/ha) of fallen trees and other coarse woody debris on the ground.
  • Two or more canopy layers, multi-species canopy dominated by large (>50 cm dbh) overstorey trees (typically 247–457 stems/ha, although densities as low as 86 stems/ha are possible where large diameter trees are present).
  • Moderate to high (60–80%) canopy closure.
  • Five or more large trees/ha (>50 cm dbh) with various deformities (e.g., large cavities, broken tops, dwarf mistletoe infections).
  • Five or more large (>50 cm dbh) snags/ha.
  • Accumulations (>100 m3/ha) of fallen trees and other coarse woody debris on the ground.

Dryer ecosystems: Sub-maritime Coastal Western Hemlock and Mountain Hemlock, and Interior Douglas-fir and Engelmann Spruce–Sub–Alpine Fir Biogeoclimatic Zone

Natural Disturbances: Infrequent stand-initiating events to frequent stand-maintaining fires; however, fire suppression has increased the frequency of stand-initiating events.

Suitable habitat characteristics
  • Three or more canopy layers, multi-species canopy dominated by large (>50 cm dbh) overstorey trees (typically 173–247 stems/ha, although densities as low as 86 stems/ha are possible where large diameter trees are present).
  • Moderate to high (60–85%) canopy closure.
  • Five or more large trees/ha (>30 cm dbh) with various deformities (e.g., large cavities, broken tops, dwarf mistletoe infections).
  • Seven or more large (>50 cm dbh) snags/ha.
  • Accumulations (>268 m3/ha) of fallen trees and other coarse woody debris on the ground.
  • Two or more canopy layers, multi-species canopy dominated by large (>30 cm dbh) overstorey trees (typically >247 stems/ha).
  • Stands must contain 20% Fd and/or Hw in the overstorey.
  • Greater than 50% canopy closure.
  • Five or more large trees/ha (>30 cm dbh) with various deformities (e.g., large cavities, broken tops, dwarf mistletoe infections).
  • Five or more large (>30 cm dbh) snags/ha.
  • Accumulations (>100 m3/ha) of fallen trees and other coarse woody debris on the ground.