Wednesday, June 23, 2010

The meadowlarks of Andrews

Some more shots from the Andrews Museum. Earlier this spring Tim and I had the chance to compare the 2 meadowlark species at Tiscornia. Andrews had a couple specimens of each and we spent the bulk of the time comparing the two species.

I'm not sure that I've ever heard of an albino meadowlark, but apparently they exist...
The collection info (species, sex, date of collection) was lost on this specimen. It's mounted singing, if it was heard singing that would have been helpful though if collected in the 60's, (like a lot of the stuff there), there may not have even been tapes for people to learn the songs. The distribution of yellow on the malar suggests a female Western, so if so, it probably wasn't singing anyway (but could have called).

Next are a couple Eastern Meadowlarks, with completely cream malars, Pyle would make these females. One was collected in Berrien in June 1961, data is lost on the other. Only one had a tail worth reviewing (the other was quite ragged and missing at least 3 feathers). There are 2 solid white outer tail feathers with narrow terminal shaft streaks, r4 has mostly white outer with some buffy inner, and r3 has a little bit of white extending out along the vane. This is closest to Pyle type B, but has less white on r3 than he illustrates most Easterns' as having.

Now we move on to some Westerns. This one is a male Western (almost entirely yellow malar), specimen 885, with unknown collection data.
Its tail is actually quite similar to the previous bird, 2 white outer tail feathers, with a fair amount of white on r4, though the buffiness on this feather is on the outer edge and the white on the inner, a difference that would probably be hard to see in the field. This pattern is very similar to the classic Pyle D meadowlark tail,

Next is a female Western, with a square of yellow on the malar. This is specimen 1768, collected in Berrien in summer of 1978.
This bird also has r4 with buffy outer edge and a white inner edge. Note that the terminal shaft streaks on r5 and r6 are actually sections of patterning rather than the very narrow streak that the Eastern had.

Next is specimen 309, unidentified by the collector. It's another straightforward Western, with extensive yellow on the malar, likely a male:
Its tail has even more patterning of the terminal streak on r5 and r6 than the last bird:

Finally we come to this bird which caused us some problems, specimen 277, collected in Berrien in Sept 1962. We looked and looked at the face, the yellow didn't seem to extend onto the malar tract which would seem to make it a female Eastern. Even if there is a narrow stretch of yellow along the edge of the feather tract, that would be consistent with male Eastern (female Western has a square of yellow and male Western extensive yellow):
The pattern of white on the tail however, is exactly what is shown in Pyle for Western. The plate could literally have been drawn from this specimen.
I'm not sure what it was. I wish we'd photo'd the upperparts with some of the known birds.
Below is a comparison of 2 Western's on top, and an Eastern on the bottom:

It was interesting how many of the Berrien specimens were Western. Currently Eastern probably outnumbers Western in the county by at least 100:1. Last year there were no Western's on known territories; I can't remember if there are any known in the county at present. Clearly there seems to be some shift in the ranges or local population (unless the collectors focused on what seemed like interesting birds to them, which obviously would bias the results).
I wish I'd looked at the flank streaking on the specimens (though their condition would might have made it hard to peek under the wings). The streaking of our April Western was a lot finer than the Eastern we photo'd the same morning. It'd be interesting to see how consistent that is.
With an infinite amount of time it'd be nice to go over to the U of M museum and go through some of their specimens...

No comments: