The general phenomenon of passerine birds forming mixed flocks in our area, especially in autumn and winter is well known (for a long time). The species you
mention are typically part of this, (plus thornbills and others). I don’t think there is anything to suggest that it happens any more or less on hill tops than other places, where there is sufficient habitat. Investigating that question, if anyone wishes to
do so, would take a lot of work (because there are so many variables). Some of the species are migrants but some are residents. These are normally a moving collective where birds join and leave, but the flocks themselves are not necessarily migrating.
From: Canberrabirds [
On Behalf Of Christine via Canberrabirds
Sent: Wednesday, 29 March, 2023 12:42 PM
To: COG chatline
Subject: [Canberrabirds] Interesting mixed flocks
on the weekend I came across a couple of interesting mixed feeding / migrating flocks. Both were on hill tops, and seemed to be slow moving, and even temporarily incorporating sedentary birds as they moved through.
It is the first time I have witnessed such groups and it raised a few questions about where the birds were migrating to, do they usually migrate in mixed flocks, why were they on hill tops, and will some of them stay here in Canberra?
The first flock was late afternoon on Black Mountain summit. There were at least 20 female and immature Golden Whistlers, several Grey Fantails, a Rufous Whistler, some White-throated TreeCreepers, and one Rufous Fantail.
The second flock was on top of Red Hill, on Saturday morning. It comprised 50+ Silvereyes, at least 6 Golden Whistlers (again female and Immature only), 2 White-throated Gerygones, several Grey Fantails and a female Scarlet Robin. Birds
which seemed to temporarily join this group included Superb Fairywrens and Red-browed Finch.
Thanks for any information on this behaviour,