Lincoln's Sparrow plumage question

[Julie Brown]

Image made at Red Rock State Park in Sedona, Arizona on 3-29-13. I am speculating that this bird is a juvenile from the gray head and yellow gape. Is it true that juvenile plumage is only seen on the breeding grounds?

[Declan Troy]

Julie,
The simple answer is the juvenal plumage of sparrows is generally only seen in the breeding areas.

One can quickly get confounded by two similar words here. Juvenile is a term referring to a young bird; the upper limit of which is rather vague. Juvenal is the first, often distinctive plumage a bird has. The juvenal plumage of sparrows is generally retained for a brief period and is quickly replaced by the "first basic" which is what one sees during the fall and winter. One might loosely refer to these first basic birds as juvenile or immature long past the moltling out of the juvenal plumage. You might look at the plumages of white-crowned sparrows where the juvenal, first basic, and adult plumages are quite distinctive (and despite how widespread it is relatively few birders see the juvenal plumage). Dark-eyed Junco is another where the brown streaky juvenal plumage is often not even shown in guides.

[Paul Guris]

I agree with Declan. We have juvenile Chipping Sparrows showing up in our yard now, but by late August or so thy will have all molted into first basic, which you can also call "immature" as compared to "juvenile". I think your bird is in the midst of molt since some of the feathers look very fresh, especially the wing coverts, while other feather look like crap on a stick (sorry for the technical ornithological term) like the head.

[Julie Brown]

Thank you Declan and Paul for helping me to understand the difference between juvenile and juvenal. Perhaps I should use the word immature when describing sub-adult birds? Paul, you mentioned that this bird was molting, which I suspected. Was I correct to assume that it is not an adult? Might it have been molting from basic plumage into adult plumage-given the early spring date?

[Paul Guris]

Julie, I'm not really sure on the age. Looking around at photos on the web, the yellowish gape doesn't seem to be unusual well into the year so I don't think that's telling. It does appear that the breast is pretty buffy and heavily streaked, and adults usually have nice fine streaks. So if I had to bet five bucks, I'd say a first winter bird molting into adult plumage but I'd rather hear from somebody west of me who sees these things a lot more frequently than I do.

[Declan Troy]

The bird is certainly molting but that is what birds do. To distinguish if this bird had been born in 2012 or if were older one needs a clear view of the primary coverts and even then one can't always tell. My guess, with low confidence, is that this is an adult bird (a younger bird should have more pointy, less buff tipped coverts) but the angle is not ideal for a proper assessment.

[Julie Brown]

Thanks again, Paul and Declan. I appreciate the additional discussion from both of you. It is always fun for me to learn more about life stages and plumages.