Friday, October 30, 2015

Rocky Mountain Arsenal

October 29, 2015

Richard Stevens:

I spent the last 2.5 hours of daylight at Rocky Mountain Arsenal.  Winds were 15 mph, gusts to 21 mph; temperature was 56 degrees at 1700 hours.  I pushed the closing at sunset time limit; however, I did get out before the gate was closed.

At first, I was going to walk the Prairie Trail to Havana Ponds hoping for some shorebirds at the mudflats.  Winds at the trailhead were at least 15 mph.  Changed my mind and drove to Lower Derby Lake.

Hundreds of waterfowl were on the lake.  A good mix with Mallards, Gadwalls, Northern Shovelers, Northern Pintail Ducks, American Wigeons, Blue-winged Teal, Green-winged Teal, Canvasback, Redheads, Ring-necked Ducks, Lesser Scaups, one Greater Scaup, Buffleheads, Hooded Mergansers, Common Mergansers, and Common Goldeneyes.

The wind continued to strengthen so I decided to walk around Marys Lake, which is down in a depression.  Perhaps a Swamp Sparrow could be found?

A walk along the ditch/canal along the southern side of Lake Mary was enjoyable.  The first bird I found will be described later.  I ran into a Wilson's Snipe, two Virginia Rails, fourteen Song Sparrows and a wren.

A short tailed, quite dark brown wren lacked the white back streaks of a Sedge Wren or Marsh Wren.  It was also too dark brown in color.  It was a Winter Wren.  It rattled several times and sounded like a Winter Wren and not a Pacific Wren.

When I reached the western end of the drainage, I crossed over to the north side of the ditch and returned to the east end of Marys Lake.  A Swamp Sparrow popped out of the cattails near the northwestern end of the detour loop going northward toward the lake.

Now the mystery shorebird. It was the size of a pump Killdeer.  As it walked along a muddy clearing in the eastern end of the ditch, it appeared to be an overall grayish bird with a short bill and dull greenish relatively short legs.  When it flew (only about 10-15 feet to the west), it again appeared to be quite gray, darker gray wings with a pale gray tail.  A whitish wing stripe was quite evident on gray pointed wings that were darker at the tips.

A female non breeding Ruff looks similar to the description except would show white "U" shaped upper tail coverts.  A Dunlin would also have a whitish tail with darker center stripe.  A Red Knot would be long winged as this bird and have a grayish tail, short straight bill.  

Would a Red Knot be walking along a muddy shore of a swallow stream?

Comments welcomed!

No comments: