Friday, September 16, 2011

Young Birds in September (Video)

There's been a cluster of as many as 11 American goldfinches around our purple coneflower seed heads and our feeders in the last 2-3 days, and when we see them up close we notice some have a very fluffy look, not the sleek plumage that mature birds show. I'm not sure whether this is due to their routine late-summer molt in which they transition to winter plumage (at which time the males are no longer bright yellow, but look very similar to the more olive-colored females), or if this is just a normal phase of plumage development for very young goldfinches. Perhaps both! Goldfinches breed late in the season, perhaps bearing a close linkage to the life cycle of the thistle seeds that are a preferred food. Goldfinches are rare in their exclusive preference for a seed-based diet; most other seed eaters also eat some insects.

Also, I got a short video of a female northern cardinal with a juvenile by our front step last evening. Adult females and juveniles look similar, but the adults' beaks are red, while juveniles have dark beaks. In this clip, taken through a window, you'll see the mother feeding the juvie several times -- it looks as if she finds a seed, deftly shells it, spits out the shell, and then feeds the inner kernel to the juvenile. Given the time of year, this would most likely be offspring from a second brood of the season.

Speaking of juveniles, I recently learned that in the birding world the word is often spelled juvenal. Apparently that spelling used to be in general use and meant the same as juvenile, but that usage has become archaic. (However, when capitalized it refers to Juvenal (Decimus Junius Juvenalis, A.D. 60?-140?), a Roman satirist.)

I'd seen this spelling in ornithology blogs and wondered about it. My American Heritage dictionary gives this definition:
adj. Of or pertaining to a young bird having its first plumage of true feathers though often lacking the characteristics of its species: juvenal plumage
Being interested in words and usage issues, I looked further and found a discussion in the ornithology journal The Auk, contrasting the use of juvenal (traditionally used as an adjective only, though the writer recommended extending this use to noun status) to refer to a specific stage of plumage in young birds, versus juvenile, as either a noun or adjective, referring more generally to any immature bird. So there you have it.

1 comment:

Dan Tallman said...

Good Blog, Penny. I have noticed that Birds of North America consistently uses the word juvenal.