The Lesser Slave Lake Bird Observatory is still monitoring locally breeding songbirds, but a few birds have already left their summer homes. This dispersal netted us a young Varied Thrush – our first captured during MAPS and only the ninth we have ever banded. While range maps will tell you this species cannot be found east of the Rockies, a small breeding population lives on Marten Mountain. On your hike to Lily Lake, listen for the steady flute-like whistle of our anomalous Varied Thrush.
Above: This young fellow was the first of MAPS and the earliest in the year we have ever caught a Varied Thrush (most of the others were in late August or September).
Birders new and old should understand how birds are grouped and sorted. When we classify birds scientifically, we first begin by clustering birds into orders: songbirds, waterfowl, hawks, woodpeckers, etc. Organisms were first grouped together based off similar appearances, vocalizations, or behaviour, but modern advancements in gene sequencing have revealed unexpected relationships. For example, we now know that falcons are more closely related to parrots than they are to hawks, so falcons are listed after parrots in modern field guides.
Orders are then split into families. It may sound daunting, but sparrows, warblers, and blackbirds are all families of songbirds you are already familiar with. As their name suggests, Varied Thrush are members of the thrush family, Turdidae. This family branched from a common ancestor who likely lived in Eastern Russia and crossed the Atlantic several times 11 to 4 million years ago to further evolve into our thrushes (Nagy et al. 2019).
Other thrushes that are more common locally include American Robin, Swainson’s Thrush, and Hermit Thrush. All these species are related, but only the Swainson’s Thrush and Hermit Thrush are grouped together in our next classification layer – the genus. If you have ever read a scientific name, the genus is the first word of that name, followed by the specific name that sets each organism apart as a species. The different genus classifications tell us that, although they are similar in size, Varied Thrush (Ixoreus naevius) are not as closely related to American Robins (Turdus migratorius) as Swainson’s Thrush (Catharus ustulatus) are to Hermit Thrush (Catharus guttatus).
Swainson’s Thrush 
Hermit Thrush 
American Robin
In general, those birds at the start of taxonomic lists are thought to have split off earlier from a common ancestor and are ‘older’ species than those at the end of the list. For example, Swainson’s Thrush are thought to have existed for 2.6 million years, so they are listed before American Robins who evolved more recently around 320,000 years ago (Topp et al. 2013).
If you are curious about the most up-to-date taxonomy, changes are quickly updated on many websites and apps like Merlin or eBird. Now that you have learned some basic taxonomy, get out and apply your newfound knowledge before our migratory birds begin their exodus from the boreal! By July 12, we will have begun Fall Migration Monitoring.
By Robyn Perkins, LSLBO Bander-in-Charge
Nagy J, Végvári Z, Varga Z. 2019. Phylogeny, migration and life history: filling the gaps in the origin and biogeography of the Turdus thrushes. Journal of Ornithology. 160: 529-643. https://doi.org/10.1007/s10336-019-01632-3
Topp CM, Pruett CL, McCracken KG, Winker K. 2013. How migratory thrushes conquered northern North America: a comparative phylogeography approach. PeerJ. 1: e206. https://doi.org/10.7717/peerj.206
