Maybe reasonable to suggest that any ID to species of an isolated immature of these 2 be regarded as not possible to know which it is. Hard to prove anyway
unless you have been watching them since leaving the nest. If it is with an adult it may help (and even then proximity is not always proof unless the adult is clearly a parent). By now immatures should be independent. So is there a method of keeping count
of unknown either option as they pass through?
Sent: Saturday, 11 April, 2020 8:57 AM
To: 'COG Chat'
Subject: [canberrabirds] Leaden/Satin Flycatchers
There have been a surprising number of Flycatcher reports in the first 10 days of April. Checking the BIRD INFO on the COG web site shows it is rather late for them (particularly for the Satin)
still to be present/coming through.
This includes a male Satin Flycatcher seen on 8 April. However, interrogating the lists on the eBird Australia map over the past month shows that only in some cases do they mention a female,
otherwise it’s not stated, and with few photos.
I suspect quite a few were immatures - I deliberately didn’t go into the juveniles/immatures in my COG presentation on 12 February because it made it even more complicated!
I now regret that I didn’t at least warn the audience that juveniles are even more similar, and that we might expect some immature Satins to come through in March during the period of return
I’ve checked the Australian Bird Guide (ABG) again - this says (and shows) that the immatures of both species retain their juvenile wings markings – in both cases brownish!! HANZAB also shows
this, but as usual gives a much more detailed (but not necessarily a clearer) description
So they’re even harder if not impossible to separate, as well as from the Satin female.
However, a female Satin should seem darker on the head than back, and should also lack the short pale bar along the shoulder (this difference is clearly shown in the ABG but is less clear in
HANZAB). The brown on the wing of the immatures of either species is probably also more extensive.
I hope this will help in the event that any more female/immature flycatchers are observed over the next few days – if so please let me know if you have any difficulties with the identification (a good photo would help!), or if you disagree
with the above as I’m still learning as I go along.