Assertion: barred owl's expansion | /r/AtLocation | evidence
Facets:
value: by the 1940s
type: TEMPORAL
Source sentences:
text: Westward expansion through the boreal forests of Canada was in evidence by the 1940s (Wright and Hayward 1998, Houston and McGowan 1999), and the species reached British Columbia and western Montana by the 1960s (Grant 1966, Shea 1974).