I’m pretty sure staff have said not to annotate observations with multiple life stages; I can’t find the exact posts, but here are 3 posts where staff have implied this:
https://forum.inaturalist.org/t/lets-talk-annotations/627/15
https://forum.inaturalist.org/t/lets-talk-annotations/627/40
https://forum.inaturalist.org/t/lets-talk-annotations/627/441
[I’d also like to note that for some bird species, it can take 2+ years for them to become adults, so juveniles/immatures are present year round too.] If you have the time and energy, I’d recommend asking the observer to duplicate the observation for each life stage.