Pairs within flocks.

[Wild-Woman]

I was wondering if anyone knows whether redwings and fieldfares actually pair within their flocks? I know this can happen with geese and that family units remain together. Just curious.

[Ferret]

I think answer to your question for Feildfare is yes, sometimes, but not in the same way that geese do, i.e. not forming permanent pair bonds as geese do.
Below is an extract from BWPi for Feildfare which suggests pairing may start during the spring migration.

(1) General. ♂♂ usually arrive on breeding grounds c. 1 week before ♀♀ . In Switzerland, young birds arrive later than older birds. In southern Norway, pre-laying period c. 2–3 weeks.
(2) Pair-bonding behaviour. Some birds establish pair-bond during spring migration . Territorial disputes and nest-site searching recorded in passage flocks . Pair-formation seldom reported, taking place very quickly, e.g. Courtship-song heard only on 1 day. Preliminaries to pair-formation take place mostly on open ground, sometimes far from nesting area.

But for Redwing it seems lass likly, although there does not seem to be as much study for this species. This it what BWPi says

Heterosexual Behaviour
Little known. (1) General. In Moscow region, pair-formation takes place within 3–5 days and nest-building within 7–8 days of arrival of ♂♂. In Novgorod region (USSR), similarly c. 1 week between arrival and start of nesting. (2) Pair-formation. Other than song-display of ♂, no information. (3) Courtship-feeding. Not reported away from nest.

I have always thought that some species that split up after breeding then reform the next breeding season not because they remember each other but because they both remember the location of last years successful breeding site, and as they are both there it is natural to form as a pair again.

Ferret

[Wild-Woman]

Thank you Ferret. It would make sense that pair bonding may form during migration given the time factor that they have at one location.
Thanks for finding the information- it's appreciated.