Separating Satins and Leadens is a recurrent topic.
Anyone really interested is urged to consult a copy of ‘Wingspan’ for June
2003 where there is a comprehensive article by Graeme Chapman on the subject.
I am not able to reproduce this in its entirety but here are excerpts:
‘A male Satin is best regarded as a black bird
(with a blue sheen just like a Satin Bowerbird), with white underparts. One
reason they are so often misidentified undoubtedly stems from illustrations
in most of the field guides. Both painting and printing a blackish bird with
a bluish sheen is no easy task and the most useful book in this respect is
the Slater Field Guide. ... [T]he sighting needs to be made under
ideal conditions. [This photo] shows how dark a Leaden Flycatcher can be
under less than ideal conditions. A useful field character ... is the shape
of the demarcation line between throat and breast feathers. In Satins the
line tends to be down-curved, the white breast forming an obtuse angle with
the edge of the wing, whereas in Leadens it curves upwards forming an acute
angle with the edge of the wing ... [This] is not always obvious ... [illustrative
photos provided] ‘
‘Adult female Satin Flycatchers display a diagnostic
bluish sheen on the crown which is not evident in female Leadens, nor in juveniles
of either species. The density and extent of the rufous colouring on the
throat is variable and not a reliable character; adult female Satins do tend
to be darker. They are also a bit darker on the back than female Leadens,
but this is not easy to assess in the field ...’
‘Calls too are not diagnostic. ... there is great variation
in the calls of the Leaden Flycatcher, both within and between individuals
as well as from place to place. Similar variation occurs with individual
Satins and it would need a very practised ear to separate the two species.’
