Jump to content
Whatbird Community

Appropriate terminology -- immature vs. juvenile bird?

Recommended Posts

Someone already explained this to me a while back, but unfortunately it didn't stick (I forgot).  I would call this an immature Bald Eagle, but have seen it also called a juvenile.  I'm guilty of this myself.  Both terms seem to be used interchangeably, but I know one is technically correct.  Can someone please explain, in simple terms, what the difference is, which one would be (more) correct for this young eagle, and why?  Maybe provide a couple of examples, so maybe the info will stick this time.  Although this is still kind of an ID question, moderators, please move this post to a different section, if appropriate.


Link to comment
Share on other sites

To my understanding, an immature bird is any bird that isn't yet in adult plumage, while juvenile is a very specific period of a bird's first true feathers. So a bird will be in juvenile plumage until it has its first molt. There's a really good discussion here, that defines the technical terms and gives a whole bunch of examples.  

Re the eagle, I haven't progressed beyond "hey, there's an eagle!" so I can't help.

  • Like 5
Link to comment
Share on other sites

5 hours ago, PaulK said:

You asked for examples, so here are some white-crowned sparrows.

Juvenile (note streaky front)





And here's a juvenile house finch, mostly identifiable as such to me because it still has tufts of down sticking out from its head.



This is excellent! I'm hoping you will consider putting it here too:


Link to comment
Share on other sites

The Bald Eagle link you provided is the best I've seen so far.  Thank you very much Meghann.  

As a follow-up question, has anyone ever referred to young Bald Eagles as sub-adults?  I don't think it's an officially recognized term, but I've used it on occasion, to describe immature Bald Eagles that show most of the visible features of an adult.  I reserve it's use to 3 1/2+ year old birds with mostly white head and tail feathers.

Link to comment
Share on other sites

12 hours ago, PaulK said:

So a bird will be in juvenile plumage until it has its first molt.

Agree but if Tony L was still participating he would perhaps say "juvenile until the first basic plumage feather appears" ? - how you pick this out in the field I have no idea.

I use the Sibley guide to report juvenile or immature for eBird.

  • Like 2
  • Haha 2
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...