Thursday, March 9, 2017

Varied Thrush

Rare Thrush Found In Fredericton

Varied Thrush [Internet Photo]
 A very rare thrush has been seen feeding under feeders and on the ground under a large spruce tree in Fredericton this past week.  We were surprised to see it was a Varied Thrush (Ixoreus naevius).  The "Birds of New Brunswick:  An annotated List" cites only 20 sightings in the province until 2004.  These birds were mainly feeding on fruit-bearing trees and at feeders.  Some of them stayed in the area for most of the winter.

Varied Thrush [Carmella Melanson Photo]
The photo immediately above shows the bird seen here this week.  It is a male and about the size of our robin.  It is, in fact, a 'cousin' to the robin.  The thrush family (Turdidae) is represented here in NB by the American Robin, the Eastern Bluebird, the Hermit Thrush, the Veery, and the Swainson's Thrush and the much-rarer Bicknell's Thrush.  Other thrushes that show up here, like this bird, are vagrants (wanderers who move out of their normal range).

The Varied Thrush's normal range is in western North America west of the Rocky Mountains.  It spends the summer breeding season in British Columbia, Yukon and Alaska. It migrates south to the western US states to southern California for the winter.  Some are permanent residents along the Pacific coast from northern California to southern Alaska.  One of the subspecies (meruloides) occasionally wanders eastward through the northern US states and southern Canada and into the Maritime provinces.

The Varied Thrush is about the size of our robin and looks and moves much like it.  It is brightly marked with orange on the throat, eyeline, breast and wings.  It is a striking bird!  Unlike our robin it has a black line through the eye and a broad black breast band.  The back of the male is a gray colour which shows an interesting fine iridescent pattern.  The wings show a lot of orange markings.  The lower breast and flanks have gray scallops in the orange.  Its tail is a bit shorter than our robin's tail.  The female is similar to the male but the gray and black are replaced with brownish gray and the breast band is weak.  The young birds are similar to the females.  

Varied Thrush [Brian Cuming Photo]
The Varied Thrush is much more wary than our robin.  It prefers dense softwood forests and riparian habitats.  It feeds on fruit and insects preferring to feed on the ground or in trees and bushes.  It is not a common feeder bird.  

The song of this thrush is distinctive to our northwestern forests.  It is a high one-pitched sound repeated about every 10 seconds.  It is described as 'ethereal'.  On listening closely you can hear the vibration in the song.  While waiting for a chance view of our recent visitor I heard it call.  Interesting song indeed.  Even though the Varied Thrush is relatively common in its normal habitat,  logging in its breeding range has negatively affected its population numbers.  This species appears inconspicuous because it normally holds tight to the forest. It is a vital part of the western forest ecosystem.

1 comment:

  1. It is still hanging around. It was here for about 10-15 minutes yesterday.
    Brian Cuming