Wood Thrush (top left pair), Veery (top right pair), Gray-cheeked Thrush (bottom left pair), Swainson's Thrush (bottom middle pair), and Hermit Thrush (bottom right pair).
I’ve posted several short articles about bird specimens at the Royal Ontario Museum in the past couple of days. See here, here, here and here. This post will be about identification of spotted thrushes. Ignoring American Robin, the five most common thrushes in North America are Wood Thrush and four species of the Catharus genus, including Veery, Gray-cheeked Thrush, Swainson’s Thrush, and Hermit Thrush. These are all common birds occurring across large parts of North America every migration season.
In Ontario, Hermit Thrushes are the first species to arrive in the spring, by early April. Veerys, Swainson’s Thrushes and Wood Thrushes follow by middle to late April and Gray-cheeked Thrushes arrive somewhat later, by early May. During migration these birds only sing quite sparsely, so oftentimes identification has to be based of visual characters.
The five species are superficially similar, having variably spotted chests and upper sides ranging from rufous brown to gray. In this post I’ll point out some characters that are helpful for accurate identification of these thrushes. Note, however, that the text is by no means exhaustive. I will focus on characters that are visible in the photographs, which generally picture the specimens from the underside. For further details on identification please see links provided above.
The Wood Thrush is the easiest species in the group to recognize. It is slightly larger, has a chunkier appearance (larger head, thicker bill), than the Catharus thrushes. The distinct triangular-shaped breast spots, covering large parts of the creamy white breast and belly, are stunning compared to the other thrushes.
Wood Thrush: Two male specimens collected in Ontario in May 1936 and September 1936, respectively.
The Veery has a weakly spotted breast (belly largely plain). The breast base colour is warm beige and spots are comparably diffuse.
Veery: Two female specimens collected in Ontario in September 1961 and June 1929, respectively.
This species is very gray (hence the name), but note that it is not just the cheek that is gray, but also the breast, face and overall appearance; compare to Swainson’s Thrush, below. Gray-cheeked Thrush is slightly larger than other Catharus thrushes, see title image, and has slightly denser breast spotting.
Gray-cheeked Thrush: Two male specimens collected in Ontario in May 1920 and May 1941, respectively.
The Swainson’s Thrush looks similar to the Gray-cheeked Thrush, but has a warmer base color on breast and upper sides (see comparison below). Spots are slightly bolder and stretch down further on the sides than on Veery.
Swainson's Thrush: Two immature specimens collected in Ontario in September 1929 and September 1939, respectively.
This species is slightly smaller than the others, has a breast with a dingy base colour, and bold, somewhat smudged, spots.
Hermit Thrush: Two male specimens collected in California in December 1952 and August 1895, respectively.
Gray-cheeked Thrush versus Swainson’s Thrush:
I generally find that Gray-cheeked Thrush is the most difficult species to identify, perhaps partly because it is the least common species in my area. Size has never been a very useful character (oftentimes it can be misleading) and its gray colours are only subtly different from those of the Swainson’s Thrush.
The key character to look out for is the “spectacles” on the Swainson’s Thrush (buffy lores and eye-ring). However, on atypical individuals the lores are not very distinct, which could mislead you to think that you are looking at a Gray-cheeked Thrush. Moreover, the presence of an eye-ring can be difficult to detect, and often requires optimal viewing conditions.
The image below compares side views of Gray-cheeked Thrush and Swainson’s Thrush. Note the bright lores on the Swainson’s specimens (note that eye-rings are not preserved well on stuffed specimens) and the steel-gray overall appearance of the Gray-cheeked specimens compared to the more beige and brown tones on the breast, wings and upper back of the Swainson’s Thrushes .
Left: Gray-cheeked Thrush; Right: Swainson's Thrush.
That’s it for this time. I hope this comparison was useful to some of my readers. Finally, I just want to reiterate that many useful characters, including upper part colour and face details were left out in this comparison. Good birding.
Thanks to Mark Peck and the Royal Ontario Museum (ROM) for giving us access to the ROM Ornithological collection.