[obol] Re: "which finch" is getting mixed votes
- From: Mike Patterson <celata@xxxxxxxxxxxx>
- To: OBOL <obol@xxxxxxxxxxxxx>
- Date: Wed, 18 Feb 2015 07:31:46 -0800
There are some terminology issues that may be muddying the discussion.
These terms are only important because they are the terms one is going
to have to know to sort through the literature on aging birds and
understanding things like molt progression and timing.
First, Linda's finch cannot be a "1st year" bird because the photo was
taken after January 1st. 1st year (more appropriately hatch-year)
denotes a bird in it natal year. All birds magically turn into second
year birds on January first.
The expectation is that a male second year Purple Finch will look very
much like a female through October of its second year. Linda's bird
shows quite a bit of red in the head, but is still (probably) too brown.
This suggests that it is a transitional bird molting from the plumage
associated with the second-year to adult male plumage. We can therefore
argue, because it's after January first, that this is a bird in its
third year. On the data form we would call this after-second-year.
The terminology is arcane and different authorities sometimes use
different words. The language presented above is what the Bird Banding
Laboratory requires.
So, to re-cap:
Hatch-year=first-year...(juvenile/1st-basic/1st-winter may also be
bandied about, but are plumage/molt based markers, not calendar markers)
Second-year... any bird that was HY on Dec 31 becomes SY (or
after-hatch-year in birds that do not show unique SY traits)
Adult... any bird that has adult plumage. In the case of Purple
Finches, we can call males in adult plumage after-second-year, because
they have distinctive second-year plumage characters.
So, Linda's bird, because of the amount of red in the head, kind of has
to be a bird in its third year or older (after-second-year). It is
most probably a third-year bird and mathematically about two and a half
years old.
Confused? Don't be. It's still a Purple Finch. The other stuff will
not be on the test.
--
Mike Patterson
Astoria, OR
Problem? what problem?
http://www.surfbirds.com/community-blogs/northcoastdiaries/?p=2667
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