There is an ongoing debate regarding the taxonomic status of the western
race and if it is distinct from those birds in the east. This question is significant to the conservation status of this species in the west, where it has declined to a tiny fraction of its population a century ago.
[3][4][5] Populations of this species in western North America are in steep decline. The bird disappeared from British Columbia, Washington, and Oregon during the first half of the twentieth century. Eastern populations have declined as well, though not as precipitously. The
United States Fish and Wildlife Service has proposed listing the western
Distinct Population Segment (DPS) of Yellow-billed Cuckoos as threatened under the
Endangered Species Act, and the service also has proposed establishing 546,335 acres in nine western states as critical habitat for the western DPS of the yellow-billed cuckoo.
[6] However, controversy over the taxonomic status and heavy pressure from livestock and mining industries have caused the
Trump administration to attempt to end the species' protections, while the FWS has proposed a review of the bird's listing.
[7]