Musings on Broad-billed Flycatcher Identification

Identification of the Myiagra flycatchers has always been a tricky business, particularly separating female Leaden Flycatcher from female Satin Flycatcher and Broad-billed Flycatcher. It's worth having a look at this in view of a healthy exchange of views between some of us on the subject in recent weeks.
The field guides tell us that Broad-billed is distinguished from female Leaden by the male having more glossy blue upperparts; both sexes having broader, more bow-shaped bills; richer rufous colouration around the throat and breast; and different tail patterns, with Broad-billed having shorter outer tail feathers, giving its tail a more rounded rather than square-shaped appearance. This graduation in the undertail - a "layering"of three or more feathers - is regarded as a particularly salient feature in view of the difficulty of being definitive about other features. It is well-illustrated in the photograph above by Tom Tarrant.

I have over the past year found Shining Flycatchers at 22 mangrove sites on the Sunshine Coast in southeast Queensland. This predominantly tropical species had until fairly recent times been considered very rare in this part of the world, and it occurred to me that it was worth looking for other northern birds in this habitat. I was equipped  with a new kayak, giving me access to extensive areas of mangrove in the region. Broad-billed Flycatcher is known from specimens and sightings to occur as far south as the Shoalwater Bay area of the central Queensland coast - not that far north of the Sunshine Coast - where it has been seen side-by-side with Leaden Flycatcher in fringe mangrove habitat.
For the discussion here, I am grateful for input from Jeff Davies, Chris Corben, Graeme Chapman and Henry Nix, all of whom have either intricate knowledge of the identification features of the Myiagra flycatchers, or have extensive field experience with Broad-billed.

Early last month, playback of Broad-billed in the mangroves of the Pumicestone Passage near Coochin Creek attracted a single bird and a group of three birds, all of them "female Leaden" types, including the bird above. I was convinced initially that they were Broad-billed.

The slightly bowed bill shown here could fit juvenile Broad-billed, or the dark chin could indicate juvenile male Leaden - such are the identification challenges posed. This bird was the one I found by itself.
One of the group of three appeared to have particularly glossy blue upperparts but I failed to photograph it. These three birds behaved very much like a family group; if they were Leadens, it was curious that there was no sign of an adult male. However, it was pointed out that the photographs I posted on my blog of two of the four birds showed the birds did not have graduated undertails so were most unlikely to be Broad-billed. The bird shown above does not have a graduated tail so appears to be a Leaden.

Nonetheless, a return visit was in order. I went back to the area a week later but could not find the birds. I eventually hooked up with them a couple of weeks ago, finding the group of three in the original area. One of them is photographed above. Again, that slightly bow-shaped bill looks interesting, and again, no sign of an adult male Leaden. Again I saw a bird with what appeared to be glossy blue upperparts but it kept well back in the vegetation and I was unable to photograph it; I point out that at the distance this bird was on both occasions, that impression could not be verified. These birds responded vigorously to playback of both Broad-billed and Leaden calls.

This is another of the group of three, and we've had some lively discussion about whether this is a Leaden or a Broad-billed. Bear in mind that tail feathers are missing and there is some blurred vegetation in the foreground, but the key question is whether this tail is graduated or not. This is where the discussion gets intricate, so I'll try to sum it up. In a nutshell, one view is that there are at least two feather tips visible on the left side of the tail which are noticeably smaller than feathers on the right side, suggesting a conspicuously graduated tail. Another view is that there are not necessarily two feather tips on the left side, and that shadows/vegetation interference could be giving a false impression of tips. In short, we simply are not sure.

Photographs of Broad-billed show that the level of graduation varies considerably between individuals. Compare the bird above, another of Tom Tarrant's photographs, with the bird at the top of the post (note also the very pale chest colouration on this bird). Hopefully we're a little more informed now about these issues.