[cobirds] NE Las Animas County, 2/24/12

Birders,

I camped at the Beat(t)y Canyon Ranch in NE Las Animas County last night
so I could work on the OV Mesa priority block for the COBBA ii. This is
private property, and not available to the birding public, but I am sure
some people will be interested in the best of my findings today.

I spent about three hours this morning, between 5 a.m. and 8 a.m. trying
to confirm nesting by Summer Tanagers. I came close. I observed a pair
copulating, but did not see nests or nest-building. I observed a female
tanager in a unique pose: head and tail elevated while perched on a dead
saltcedar snag. The pose was reminiscent of poses seen by mating
Brown-headed Cowbirds. A male Summer Tanager heard the dry, two-syllable
calls, flew in from an unseen perch, and briefly coupled with the female.

I decided to climb to the "highlands" in the block, the summit of OV
Mesa (5,410'). This is 900 vertical feet above the cottonwoods along the
river. Midway up, it is difficult to pass a 200' vertical blockage of
red sandstone, but my reward in the zone between 4,800 feet and 5,000
feet was multiple Gray Vireos. I observed a pair exhibiting courtship
behavior.

There is a cliff band surrounding the summit massif of OV Mesa. As I
arrived at the top, I heard a singing male Scott's Oriole, but I
couldn't let go of my hand holds to use my binoculars, and the bird
stopped singing before I could see it. I walked along the north-facing
summit crest of OV Mesa and heard the song of a male Hepatic Tanager. I
got photos of this bird. A bit farther along the summit crest, I heard
and saw another pair of Hepatic Tanagers. Before I was done walking
along the rim of OV Mesa, I saw five Hepatic Tanagers, four of them
singing males. This must be prime habitat for this species.

I learned a lot about the habitat preferences of Hepatic Tanagers at the
edge of their Colorado Range. They prefer to sing on the top of dead
snags on steep slopes just below the top of mesas. My previous
experience told me that there were usually Ponderosa Pines around, if
only a few, but here, there are none. Pinon Pines seem to be necessary
in Colorado, but almost all the trees here are junipers. However, on the
north-facing hillsides here, the junipers are shaded, the micro-habitat
is wet, and the trees are much taller than other junipers lower down the
hills.

Respectfully,
Duane Nelson
Las Animas, Bent County, CO

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