I agree with Rob Leask - Leaden and Satin Flycatchers can pose nasty ID
problems. I get both in the area where I've lived for the last 12 years,
Satin as a regular breeder and Leaden as a migrant occasionally encountered
about April; despite spending a fair bit of time trying to find a real
difference between them, I still encounter birds in autumn that I struggle
to identify. I have hazy memories about a short paper on the ID problem by
John Cox (in the South Australian Orn., late 1970's or early 1980's). Can't
lay my hands on it right now but the gist of it was that he didn't think
there were any satisfactory field differences other than the colour of the
crown and upperparts: In adult males, glossy blue-black in Satin cf. leaden
grey and only slightly glossy in Leaden; in adult females, medium blue-grey
in Leaden cf. darker, more ashy grey in Satin.
These features work (provided the light is OK) but are often hard to see in
birds which spend far too much time high in the canopy. Chris Corben found a
couple of neat alternatives that work very well in adult males: In Leadens
the cut-off between the dark throat and white breast is straight or slightly
upcurved at the extreme sides of the foreneck; In Satins the cut-off always
droops downwards at the sides of the foreneck (and they may have a slightly
more extensive dark area on the throat than Leadens in any case). Male
Satins also have a blacker underside to the tail than male Leadens.
The breast feature doesn't work for females or juveniles. I don't really
know about the undertail colour, having seen very few female Leadens since I
started to pay attention to Myiagra undertails; certainly the undertail in
some female Satins looks as black as in males, so maybe there is something
in this feature. Satin strikes me as a slightly longer-looking bird than
Leaden with a louder call, but I wouldn't care to identify them on this
subjective basis alone. Is there some structural difference in the song
which I've overlooked? And does anyone know of any satisfactory means of
identifying females or juvs that does not involve getting a good look at the
upperparts?
Danny Rogers, St Andrews, Vic.
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