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GAP Analysis Predicted Distribution Map

MacGillivray's Warbler (Oporornis tolmiei)

Species Code: OPTO

Click to enlarge Range map

= Core Habitat
= Marginal Habitat

Breeding Range Map
The green area shows the predicted habitats for breeding only. The habitats were identified using 1991 satellite imagery, Breeding Bird Atlas (BBA), other datasets and experts throughout the state, as part of the Washington Gap Analysis Project. Habitats used during non-breeding months and migratory rest-stops were not mapped.

Metadata (Data about data or how the map was made)

Click to enlarge distribution map

Map with Breeding Bird Atlas records

Other maps & Information:
  • Breeding Bird Atlas
  • NatureMapping observations
    during breeding season
  • NatureMapping observations
    throughout the year

This warbler is common in most conifer forests throughout the state in shrubby microhabitats such as riparian shrubs, clear-cut regrowth, avalanche chutes, and shrubby sub-alpine meadows. It is a rare breeder in the coastal forest strip of western Washington.

Core zones were all zones above steppe, except the Sitka Spruce zone. The Sitka Spruce zone and steppe zones at the edge of the Basin were peripheral. In forested zones (except the Ponderosa Pine and Oak zones), fresh water/wetlands and forest openings and clearings were good habitats; agriculture and forests were adequate, except that mid- and late-seral forests in the wet, west-side forest zones were excluded. The Ponderosa Pine and Oak zones were treated similarly, except that non-irrigated agriculture was excluded. In steppe zones, only wetlands were included (as good habitat).

Washington breeders represent the northern subspecies O.t.tolmiei. MacGillivray's Warbler numbers have undoubtedly increased due to widespread logging.

Shrubby regrowth is one of this species' preferred habitats. As trees return and shrubs decline, its numbers also decline. They are often found breeding at very high sites, as BBA data show. Favorite habitats of this species at higher elevations are avalanche chutes dominated by alders and willows. On the Olympic Peninsula, MacGillivray's Warbler is most common in drier northeastern forests, and can be absent from some areas of the western Olympic Peninsula. On the San Juan Islands, MacGilligray's Warbler is difficult to find, with BBA records only noted from Orcas, Obstruction and Waldron Islands. It was formerly much more common in the San Juan Islands; its decline may be due to diminishing habitat in the islands or to an increase in Brown-headed Cowbirds. Despite its fondness for non-forested areas, the almost complete lack of records for this species in and around Seattle, Tacoma, and Olympia (except for the Fort Lewis property) indicates that the MacGillivray's Warbler avoids developed areas.

Translated from the Washington Gap Analysis Bird Volume by Uchenna Bright
Text edited by Gussie Litwer
Webpage designed by Dave Lester