Tuesday, November 13, 2007

A Cold Wet Day at Cherry Creek Reservoir

November 12, 2007

Another cobirder and I scoped Cherry Creek Reservoir (Arapahoe County) at first light. We could only see 3 loons out there; numbers were down quite a bit from the past week. Shortly after 7:00am, two loons took off, slowly gaining altitude, and disappearing in the low clouds. They appeared to be the pair of Pacific Loons (were definitely not Common Loons and looked too dark headed to be the Red-throated Loons.

Shortly afterwards, we picked up 2 additional pairs of eyes but still could only find one or two Common Loons left on the lake. Four or five Bonaparte's Gulls flew around the jet ski area. A small lingering group of Pelicans huddled together in the southeast corner of the lake. We stopped at two or three additional sites around the reservoir but did not locate additional loons; the weather did not cooperate.

By 9:00am it was raining, winds picked up, and temperatures dropped. My birding partners left and I had every intention of doing the same. A Sharp-shinned Hawk stood on the Gazebo at the Butterfly Hill parking area and I stopped to take a photo. A flock of about 80-100 Red-winged Blackbirds were overhead in the cottonwoods. A female Rusty Blackbird stood out in the crowd. The male could have been there also, but I was not able to pick it out in the four minutes I had before they took off for the Cottonwood Creek Loop.

Curiosity as to where this flock spent the day inspired me to walk back to the Cottonwood Creek Loop to check out the mudflats. First I followed the Butterfly Hill path north to the shoreline. This path goes through some high grasses and bushes which as usual had many sparrows. It is a good place to study White-crowned, American Tree, and Song Sparrows if one is interested. At least two races of Song Sparrows fluttered about. However stopped to check them out, slowed the trip back to the Cottonwood Loop.

By the time I made it down to the Bird Observatory Platform at the Cottonwood Creek Loop, the flock of blackbirds had moved on (who knows where). Water levels have been rising all week and the mudflats where Glenn Walbek first found the Rusty Blackbirds 10 days ago have disappeared. Continuing east, I did not find any mudflats; nightly snows in the mountains and warm daily temperatures have brought high water levels to the Denver lakes.

At one gap between the cattails along the southeastern edge of the lake, I could see that one Common Loon and the Red Phalarope were still around.

Skies cleared somewhat and temperatures rose a bit, so I decided to continue hiking east to where many blackbirds usually spend the day in the cottonwoods over the cattails just west of Cherry Creek.

Along the way, I found a pair of Great Horned Owls, my first at the park in almost a year. West Nile Virus?, human growth, bird counts seem to be way down from past years.

In the next four and a half hours, I took about 150 GPS waypoints. For ten years, I hiked Cherry Creek Reservoir 2 or 3 times a week and entered bird counts on graph paper. Now with the help of my computer, I plan to transfer the count coordinates to GPS waypoints.

Once I reached the woods where the main road goes over Cherry Creek, I doubled back to the Shooting Range area. Hundreds of blackbirds were in the Russian Olive trees here. Unfortunately once I reached the area, most of the blackbirds were Starlings. No Rusty Blackbirds, but my interest in getting GPS waypoints rose, so I decided to walk the blockaded road south from the shooting range and turn east on the south side of the 12 mile beaver ponds.

Along the way, I ran into 9 Red-tailed Hawks (including 1 dark morph), 3 Northern Harriers, and 4 American Kestrels. A Prairie Falcon stood on the telephone poles next to the southwestern prairie dog town.

I did not pick up a late Common Yellowthroat or Marsh Wren at the Beaver Ponds. Several flocks of American Goldfinches picked away at the cattails. A pair of Downy Woodpeckers worked the trees around the 12 mile picnic area. No warblers, shorebirds except Killdeer, hundreds of starlings, a few Red-winged Blackbirds, still no Rusty Blackbirds.

The day's Black-billed Magpie count was only 3 down from the last 10 year mean average for November (again, got to love computers to keep track of all this for you). They even can draw up a pie chart if one so desires!

As I crossed over the model airplane runway area, a Northern Shrike flew from the Butterfly Hill area southeast toward the shooting range. Two dozen Horned Larks (but no Snow Buntings) wandered around the short grasses here.

No gulls stood on the telephone poles outlining the southwest marina and I left Cherry Creek Reservoir around 3:30 pm.

No comments: