SWAINSON'S THRUSH
Catharus ustulatus
Order:  Passeriformes

Family:  Turdidae

 Alpha Code:  SWTH                    AOU#:  758.0

Band Size:  1B
    Swainson's Thrushes are not particularly common birds in the Santa Monica Mountains at the Zuma Canyon Bird Banding station (only 22 encounters in seven years).  But since this bird can easily be mistaken for a Hermit Thrush, I thought the inclusion of its Species Account would be useful.  Swainson's and Hermit thrushes have an almost sympatric breeding range, but Swainson's Thrushes do not winter in the U.S. but rather in southern Mexico and into Central America.  There are six subspecies in two groups.  The key problem along the West coast is that the local subspecies, C.u. ustulatus, is distinct rufous uppertail coverts like Hermit Thrushes.

Thrushes are moderate sized passerines at 17-18 cm weight about 25 g.  The back is various shades of brown (see subspecies) with a rufous or reddish uppertail coverts and tail in C.u. ustulatus.   It has a bold buffy eye ring, but it never stood out for me as an obvious characteristic.  The underparts are more creamy than whitish with bold spots becoming darker and denser near the upperbreast and paler and sparser near the belly.

Bird Banding:  Through the fall and winter, it is often fairly easy to separate HY/SY from AHY/ASY birds, as HY/SY birds have unique buffy tips to the greater coverts.

     Unlike the East where there are numerous species of  thrushes, we have only the Hermit and Swainson's thrushes.  Separation of these two through binoculars in southern California is complicated because the local subspecies of Swainson's Thrush has a rufous rump.  Pyle has some very clear cut characteristics to separate the two species, Fig. 228 for Hermit Thrush and Fig. 227 for Swainson's Thrush.  Basically, p9 < p6 and p6 is emarginated in HETH, while p9 > p6 and p6 is not emarginated in SWTH. 

One other observation is timing.  Swainson's Thrushes seem to pass south through southern California in late summer/early fall (Sep-Oct) and then north in late winter/early spring (May).  In between these two times, Hermit Thrushes are common; we have never encountered a Swainson's Thrush in winter.