I guess it just depends on how we define juvenile (which we should do). Is it a technical term for some taxa? I’m no bird expert but I’d have guessed a baby bird is a juvenile.
As I remember baby bird should be pull., not juv., juvenile refers to grown up, but not sexually mature.
I don’t doubt this is true, but how many of the citizen scientists involved here will get it right? Is there any point in making distinctions people will ignore or predictably get wrong?
I admit I feel a little odd using “juvenile” for everything from a 3-year-old gull to a day-old chick, but I think it’s a reasonable thing to do in this context.
I think it could also act as a learning opportunity. People on the site often mistake one species for another or use the incorrect subspecies. However others can come along and correct them, give them some helpful information and help them gain a broader knowledge. I can see the same happening for the life stages. Sure their might be a few hiccups, but they can always get corrected.
We should get well-written instructions and guides to use those, but I think it’s possible. I use juv now anyway.
I’m not sure what pull. means as a non-bird person (pullet? or is that just chickens?) but it seems a ‘middle ground’ here that both satisfies the amateur and those who want the correct technical term would be just to have an option like ‘baby/pull/juvenine’ all in one. People could then use fields to track the more detailed distinctions.
My understanding is that a juvenile is a bird in its first full set of feathers. So if it’s naked or just has down, it’s not a juvenile, and if it has moulted out of its first set of feathers but still not an adult (some species take several years to reach their adult plumage; often the juvenile plumage looks distinct) then it’s immature, not juvenile. But I’m not sure exactly where I got that definition from or how universal it is.
And here comes the subadult! :D