A First Record of Yellow-green Vireo (Vireo flavoviridis) for British Columbia and Canada
by Rick Toochin and Gary Thoburn
Read the full article with photos here.
Introduction and Distribution
The Yellow-green Vireo (Vireo flavoviridis) is a small passerine that breeds from southern Texas (occasionally in the Rio Grande Valley) in the United States, and the western and eastern mountain ranges of northern Mexico (the Sierra Madre Occidental and Sierra Madre Oriental), south through Central America to central Panama (Howell and Webb 2010). Yellow-green Vireos are migratory birds that winter in the northern and eastern Andes and the western Amazon basin (Howell and Webb 2010, Hoyo et al. 2010). The species is casual or accidental along the Baja Peninsula of Mexico (Howell and Webb 2010). In North America, outside of southern Texas, Yellow-green Vireos are accidental in Nevada, Arizona, Louisiana, Alabama and Florida with extralimital records coming from Bermuda, Barbados and Venezuela (Hamilton et al. 2007, Hoyo et al. 2010). It is a regularly occurring species in California in the fall (Hamilton et al. 2007). In Canada there is a specimen record for Godbout Quebec taken on May 13, 1883 (Godfrey 1986). This specimen is now contested by some authorities because it is faded and damaged (Phillips 1991). Recently further examination of the bird revealed that it may actually be a Red-eyed x Philadelphia Vireo (Vireo olivaceus x Vireo philadelphicus) hybrid (Phillips 1991); but others have measured the specimen and found the measurements fall within the correct lower range to Yellow-green Vireo (Holder 1996). It is suggested that only DNA analysis will rectify the controversy (Hamilton et al. 2007). With that in mind, a recent photographic record from Vancouver, British Columbia, is likely the first record for not only the Province, but possibly for Canada.
Occurrence and Documentation
The Yellow-green Vireo is a species that regularly wanders into California in the fall from Mexico with there being eighty-two accepted by the California Bird Committee as of 2007, and is reported annually each fall (Hamilton et al. 2007). Though not recorded in Oregon or Washington, given the frequency of records for California, it seems only a matter of time before this species will be found in these two states (OFO 2012, Wahl et al. 2005, WBRC 2012). British Columbia’s and probably Canada’s first record was found in Stanley Park, in Vancouver on September 18, 2013, by one of the authors who was travelling through the area from Great Britain. The bird exhibited classic vireo behaviour by staying low in the foliage and not coming out for better views. It was watched for ten minutes and photographed before disappearing deep into the foliage. Due to the similarity to Red-eyed Vireo, and the unlikelihood of the bird being a Yellow-green Vireo, one of the two observers in the group didn’t look at the bird, believing it had to be a Red-eyed Vireo based on the range of that species. As a result the bird was at first thought to be the similar looking Red-eyed Vireo, but upon further review, the photographs proved this bird to be a Yellow-green Vireo (J. Fenneman Pers. Comm.). The timing of this record fits perfectly into California’s pattern of fall vagrancy, where Yellow-green Vireos appear in small numbers between second week of September till the third week of October (Hamilton et al. 2007). Given Red-eyed Vireo is an early migrant in the fall with birds moving in August through early September (Campbell et al. 1997), any odd looking Red-eyed Vireo seen after September 15th should be scrutinized by observers for a potential Yellow-green Vireo (Hamilton et al. 2007). This species could easily turn up in the Province again and is possible anywhere. Now that all British Columbian observers are aware of this bird, it very likely will turn up again in the future in a migrant trap or banding station somewhere in the Province.
