“Taxonomy” refers to the classification of living organisms (as species, subspecies, families, etc.) based on their characteristics, distribution, and genetics. Our understanding of species is constantly changing. Every year, some species are “split” into two or more, while others are “lumped” from multiple species into one, as we gain a better understanding of the relationships between birds.
Here is a list of birds seen in our area that have been lumped or split:
Herring Gull
Herring Gull has been split into 4 species. This split was first proposed more than two decades ago and a growing body of evidence suggests geographically separate populations of large-bodied, white-headed gulls do not interbreed as extensively as once thought. American Herring Gull is the expected species in the Americas and European Herring Gull is the expected species in Europe. Mongolian Gull breeds across Mongolia and northeastern China, and Vega Gull rounds out the distribution in northern Siberia.
- American Herring Gull (Larus smithsonianus) – Anyone who has previously reported “Herring Gull” locally in eBird will see their observations appear as “Herring Gull (American)”
- European Herring Gull (Larus argenteus)
- Mongolian Gull (Larus mongolicus)
- Vega Gull (Larus vegae)
House Wren
House Wren (Troglodytes aedon) has been split into 7 species. Two species are widespread on the American continents, overlapping in southern Mexico:
- Northern House Wren (Troglodytes aedon). This is now our local house wren.
- Southern House Wren (Troglodytes musculus)
Five additional species are endemic to individual Caribbean islands:
- Cozumel Wren (Troglodytes beani)
- Kalinago Wren (Troglodytes martinicensis)
- St. Lucia Wren (Troglodytes mesoleucus)
- St. Vincent Wren (Troglodytes musicus)
- Grenada Wren (Troglodytes grenadensis)
Redpolls
One notable “lump” this year is of Common, Hoary, and Lesser Redpoll into the mononymous “Redpoll” (Acanthis flammea). This is based on recent genetic evidence that differences in appearance between populations are controlled by a single shared “supergene”, and populations are otherwise lacking in genomic distinctiveness or evidence of prolonged isolation.
Accipiter Genus Split
The genus Accipiter was split into 5 genera, but no species were split. Identifying hawks in the genus Accipiter is a well-known problem worldwide, including distinguishing Sharp-shinned from Cooper’s Hawk in North America. In recent years, research has shown that Accipiter members are not all closely related. This year the long-anticipated breakup of the genus has finally occurred. The identification challenges will remain, but it will be helpful to learn the characteristics and behaviors—especially flight displays—that are unique to the new genera. Notably, the Cooper’s hawk is no longer an accipiter.
- Cooper’s Hawk (Accipiter cooperii) now becomes Cooper’s Hawk (Astur cooperii).
- Sharp-shinned Hawk (Accipiter striatus) remains Accipter striatus.
Barn Owl
Barn Owl (Tyto alba) is split into 3 species, generally separated at the continental level:
- American Barn Owl (Tyto furcata) of North and South America
- Western Barn Owl (Tyto alba) of Europe, Africa, and the Middle East (east to central Iran)
- Eastern Barn Owl (Tyto javanica) of Pakistan, India, and Sri Lanka east through Southeast Asia, Indonesia, and Australasia.
These owls generally look similar, but some subtle differences in coloration and pattern may be apparent, although each has multiple subspecies which also vary intraspecifically. Genetic differences were one of the main reasons for the split, but are supported by vocal differences, especially the unique clicking vocalization made by American Barn Owl, which appears not to be present in other Barn Owl taxa.
For more details and information on other species changes:
https://ebird.org/news/2024-taxonomy-update
https://ebird.org/region/GT-ZA/post/taxonomy-update-2024-is-here
