It’s May in central Connecticut and feeding on the path in front of us is an obvious catharus thrush. Hmmmm..the full menu choice du jour would be Swainson’s, Veery, Hermit, Grey-cheeked and possibly Bicknell’s. Since the latter is virtually impossible to separate from Gray-cheeked under normal field conditions, we’ll lump it under Grey-cheeked since, for all intents and purposes, they share some of the same field marks which help separate these two taxa from their similar cousins.

The view is largely close and unobscured – a small thrush with tail raised slightly above the wings, a rather well marked upper breast and pale area around the eye. The blackish spots that reach up to form a well-defined malar stripe are too prominent for Veery, which is more muted in these areas (but migrants from some northern and western populations can be duller above with more obvious malar markings, N.Bonomo pers. comm). Veery’s tend to show a nice buff-washed breast with muted markings than shown here. The pale area around the eye is a little more obvious than we expect on Gray-cheeked, and the overall plumage looks a tad warm, so we quickly eliminate that and move onto Swainson’s and Hermit Thrush. Two-down, two-to go! 

Swainson’s have nice buff ‘spectacles’ joined to a buff supra-loral line that often look prominent in the field and give Swainson’s a rather characteristic ”surprised” look. The upper breast spotting on all catharus thrushes can be variable, but generally smaller spots are present in Veery and Grey-cheeked and are confined more to the upper breast.

On Swainson’s and Hermit Thrush they tend to be slightly darker and rounded and extend further down on to the belly and upper flanks, becoming dappled gray on the flanks. On Swainson’s they are overlain, especially in young birds with a warm buff wash across the upper breast. Our mystery bird has a pale eyering, but it doesn’t look particularly thick and lacks the pale adjoining line between the eye and bill. The only other catharus thrush with such a prominent eyering is Hermit Thrush.

It should be noted here that most catharus thrushes show some pale areas around the eyes but it is often diffuse and not a classic eye ring as is often characteristic of Hermit Thrush.

In Hermit Thrush, the eye ring is often narrow, but well defined, especially on the lower part of the eye. They also have rather large, round blackish spots which often coalesce more to form rather distinct spots on the upper breast merging together to form a rather distinct and noticeable malar stripe.

In life, the  tail is slowly lifted and cocked as it feeds – another character of Hermit Thrush compared with it’s congeners’ which do not habitually cock their tails to the extent Hermit Thrushes do. In life, Hermit Thrushes are rather warm brown with buff-brown (not grayish) rear flanks a contrasting rufous tone to their tails, which is one of the better characters to identify this species.

However, under the dark forest canopy, in these conditions this feature can be decidedly subtler so it pays not to rule out Hermit Thrush if a thrush appears NOT to have a rufous tail. At range, Hermit Thrushes exhibit bronze bases to the primaries forming a subtle contrasting “panel” on the wing - one of the features I often check for. 

Bicknell’s Thrush can superficially resemble Hermit Thrush more than Gray-cheeked sometimes due to the former’s warmer brown tones to the upper parts and tail, but I will deal with Bicknell’s in another post soon. Indeed, some warmer-plumages Bicknell’s I feel may be mistaken for Hermit Thrushes than perhaps many might realize.

One other plumage minutiae is in the wing formula between Hermit and Gray-cheeked with emarginations falling closer to the tip of the wing point in Gray-cheeked and well described and Illustrated by David Sibley here.

So to summarize the pro-Hermit Thrush features:

• Rufous tail- often held cocked

• Dark, often blackish spots

• Greyish-brown flanks

• Narrow but defined eyering

• Often contrasting bronze panel at the base of primaries

This confiding Hermit Thrush was photographed by myself in East Rock Park, New Haven in May.

I will post the answer in the next couple of days with a breakdown of the ID.

May, Connecticut

The upper, median wingbar is clean white and seems to lack the pointed dark centres typical of HY Bullock’s (even allowing for the scaps covering the upper wingbar, I think you’d see the pointed centres poking out from underneath). The feathering in front of the eye is slightly ruffled, but I don’t think there is a dark loral line, the kind I’d want to see on a putative Bullock’s. Also, the crown is fairly uniform without a subtler, paler supercilium. In Bullock’s the malar and sides of the earcoverts are often the brightest yellow (rather than the breast) superficially reminiscent of a fall Cape May Warbler.

HY female Baltimore Oriole, Central Park, NY, Dec. 2011 (David Speiser).The areas of the head, upper breast and vent are predominantly orange-toned, which is good for Baltimore,not clearer yellow as in Bullock's. The head pattern, lacking dark lores and a paler, contrasting supercilium are also pro-Baltimore features.

To compare, here’s a link to a similar-plumaged Bullock’s in New Brunswick, that has the appropriate credentials. Thanks to Louis Bevier for comments and bringing this link to my attention and to David for allowing me to use his great shots!

http://www.flickr.com/photos/stubirdnb/6517531719/

Birds that look like this, in early winter, often throw up that same question. Bullock’s Oriole is a likely vagrant to New England. So if you were faced with this bird in the field, what features would you look for on a putative Bullock’s Oriole that would help eliminate a late Baltimore?

What do you think?  Is it all just a load of Bullock’s?

A solution to follow, but in the meantime, have a go and send in comments!