Distribution Map - Green Heron (Butorides virescens)

GAP Analysis Predicted Distribution Map

Green Heron (Butorides virescens)

Species Code: BUST

Breeding Range Map
The green area shows the predicted habitats for breeding only.
© NatureMapping Program

+ enlarge map

Predicted breeding range

= Core Habitat
= Marginal Habitat

Fact Sheet: Basic (Grades K-6) | Advanced

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.

Observations | Historic Gap points

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

Habitat

This species is uncommon in freshwater wetlands in western Washington at lower elevations (generally below 2000 feet). These birds nest in trees, usually near water. They are not found along river courses in mountainous areas (such as the upper Skagit River), though they are present along the Columbia River west of Klickitat County. However, in eastern Washington the Green Heron is a rare breeder as there is only one recent record.

The core areas of use included the Puget Sound Douglas-fir, Cowlitz River, Willamette Valley, Woodland/Prairie Mosaic and Sitka Spruce zones west of the Cascades. The peripheral area of use was the Western Hemlock zone. All wetlands (including estuaries) and shoreline habitats were good in the core areas of use. Since this species often occurs in wetlands and small ponds well below our mapping resolution, agriculture and hardwood forest habitats were included knowing that there may be smaller pockets of habitat suitable for them if the appropriate wetland habitats are present within the larger mapped habitat. No habitat was modeled for this bird in eastern Washington.

Records from Skagit and Whatcom Counties appear to be primarily non-breeding birds, while most records from southern Snohomish County and from King, Pierce, and Thurston Counties, are from probable and confirmed nesting birds. High concentrations of records in these areas and to the north of Bellingham should be adequate to document the Green Heron's nesting status in the Puget Sound Trough area. They have been reported at Ocean City State Park in late spring and summer, indicating that breeding is likely. The scarcity of data from Willapa Hills and along the lower Columbia River could be due to either an absence of this species or simply an inadequate survey effort. In eastern Washington, there was only one valid breeding record reported during the BBA period; it was from Chelan County. Green Herons were not reported in Washington until 1939. Scattered summer observations were reported after 1939 in western Washington and the first nest was discovered in 1960. There is a nest in Wahkiakum County that has been active for at least 15 years.

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