A. Poole

Yellow-billed Cuckoo (Coccyzus americanus)

STATUS AND RANK COMMENTS Yellow billed Cuckoo (Coccyzus americanus) populations west of the Continental Divide were first proposed for protection under the Federal Endangered Species Act (ESA) in 1986 . Following several warranted but precluded findings, western Yellow-billed Cuckoos were proposed for listing as a Threatened Distinct Population Segment (DPS) by the U.S. Fish and Wildlife Service in 2013 . In 2014, the Yellow-billed Cuckoo western DPS was officially designated as Threatened under the ESA . In this context it is important to note that the species occurs on both sides of the Continental Divide in Wyoming (see Distribution and Range, below), but the ESA status applies only to individuals occurring west of the Divide.

Great Blue Heron (Ardea herodias)

Three subspecies of the Great Blue Heron are recognized in North America, two of which occur in British Columbia: A. herodias herodias, which occurs across most of North America, and A. herodias fannini, which occurs only on the Pacific coast from Washington to Alaska (Payne 1979; Hancock and Kushlan 1984; Cannings 1998). The separation of these subspecies is based on differences in plumage, morphology, and migratory behaviour (Hancock and Elliott 1978; Payne 1979).

Yellow-billed Loon (Gavia adamsii)

Binford MS) has necessitated a revaluation of the characters used for identification, both in the field and in the hand. Field guide treatment is often inaccurate and invariably incomplete, especially in regard to birds in gray-brown plumage. The more technical literature not only is widely scattered and poorly digested for use in modern field identifi.cation, but also neglects some of the most important distinguishing characteristics. Confusion on the part of some ornithologists has led to the misidentification of museum specimens, including a supposed Yellow-billed Loon from Colorado (Remsen and Binford MS). The following discussion is based on published literature; specimens in the California Academy of Sciences, San Francisco (CAS), and the Museum of Vertebrate Zoology, Berkeley (MVZ); published and unpublished photographs of living birds; communications with birders; notes in the files of regional editors of American Birds; and our own field experience. Comparisons are confined to the Common Loon (Gavia iraruer), the only species with which confusion is likely. The reader is referred to Figures 1 (adamsii) and 2 (iraruer), which depict some of the distinguishing characteristics discussed below. The timing and sequence of molts and plumages are nearly identical in the two species (Godfrey 1962) and thus are of no use in field separation. Both species are sexually monomorphic except in size.