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Thursday, January 25, 2007

Birding on Ice

Last Monday, I diverted myself to Boulder Creek just west of 75th street in W. Boulder. Wedged between the Boulder water treatment plant to the south, private lands to the west and south, and off-limits open space (how's that for an oxymoron) to the east, this little stretch of creek offers about 1/2 mile of great riparian birding.

The lower half of this stretch used to stay open all winter, warmed by the effluent of the water treatment plant. The birding there often was often proportional to the severity of the winter- as other stretches of the creek froze, birds would take up residence in the artificially warmed environment.

Well, it turned out that another municipal water supply intake was below the output of the treatment plant. Seems that they objected to this arrangement (can't imagine why), so a couple of years ago the outlet pipe was extended to emerge just downstream of their water supply intake. The problem is that the warm water now flows through a closed section of open space- major bummer for winter birding.

So back to the tale of my recent visit- with our 5 weeks of successive snowstorms and cold weather, the stretch of creek was mostly frozen and snow covered. As much as I missed the steaming treated water, it was cool to see the creek in its natural icy state. A few very narrow stretches of fast-moving water were still open, and sure enough, birds were taking advantage of the openings. It is really fun to see American Dippers dive right into the fast water, stay down for a while, and then whip back onto the ice shelf, kind of like mini gray penguins. They seemed to be coming up with plenty of caddis fly larvae and little snails. Some of their favorite perches were littered with the gravely remnants of the little rocky tubes the caddis larvae live in for protection. It is spooky to think about what would happen if the current carried a dipper under the ice, with no downstream openings sometimes for well over 100 yards, but they clearly know what they are doing.

As the dippers were out on the ice instead of along the bank, the best photo angles were also from the ice. At one place I chanced crossing a side channel where deer tracks preceded me, knowing that if the ice gave way I would be wet below my knees but otherwise OK (of course, my outing would then be done, too.) This got me to a mid-stream gravel bar right by an open water race being worked by a dipper that seemed to ignore me as it dived nearby. My challenge was to try and snap some pics mid-dive. Turns out that when they dive, they dive fast and without warning since they are dipping all of the time up on the ice. So after, say, 20 fake dips, suddenly they just do one more dip and plunge in. I got lots of throw-away shots (thank goodness for digital media), but a few came through in various states of mid-dive. Interesting how their body shape sleeks down when they dive- they no longer look like their normal plump selves, instead almost taking the shape of a warbler or sparrow in flight.
Common Goldeneyes also were working the narrow, fast-running gaps in the ice. Some of the gaps were so narrow that the goldeneyes barely fit, but they would be churning along on the surface like they were on a watery treadmill, catching their breath between dives. Birds that were flushed by me or by other trail users would fly up or down stream to another open stretch where they resumed their foraging.
Another open patch hosted a Great Blue Heron, and at one point a female Common Merganser came screaming in from downstream, feet down to land right in front of me on a thread of open water. It saw me at the last minute and veered back up skyward, undoubtedly indignant at my presence along its intended landing zone. It let me know what it thought of the situation by letting fly a white stream of excrement before continuing on its way upstream to another more private spot. I took no offense, though- I was enjoying the stolen hours of winter birding way too much.

I and the Bird #41

Folks- check out I and the Bird #41 over at Snail's Eye View.

You'll see my
Bonny Birding post there, but then you've probably already read that one, right? But link over anyway- a great collection of selected birding blog entries & a great way to discover new places to visit.

Sunday, January 21, 2007

California Dreaming- Photo Update

Well, I've finally got all of my pics done from the CFO trip to Monterey Bay last September (See California Dreaming 1, 2, 3, and 4.)
Link on over to my bird photo website to check them all out, and let me know what you think.
This update includes Surf Scoter, Northern Fulmar, Pink-footed, Buller's, and Sooty Shearwaters, Black Storm-Petrel, Brandt's Cormorant, White-tailed Kite, Red-shouldered Hawk, Peregrine Falcon, Semipalmated Plover, Black Oystercatcher, Willet, Long-billed Curlew, Marbled Godwit, Black Turnstone, Surfbird, Western Sandpiper, Red-necked Phalarope, Heermann's, Western, Glaucous-winged, and Sapine's Gulls, Elegant Tern, South Polar Skua, Pomarine & Parasitic Jaegers, Common Murre, Pigeon Guillemot, Marbled Murrelet, Rhinoceros Auklet, Townsend's Warbler, Song Sparrow, and Tricolored & Brewer's Blackbirds. Also Humpback & Killer Whales, Northern Fur Seal, California Sea Lion, California Sea Otter, and Ocean Sunfish.

Tuesday, January 16, 2007

Chihuahuan Ravens in Boulder County

While observing a Virginia Rail and Wilson's Snipe (see post below) yesterday, I was alerted to a pair of oncoming ravens by their calls. It struck me that the calls were thin and high, unlike the Common Ravens I commonly hear around Boulder. I snapped a string of shots of the closer bird as it flew by, which provided fodder for analysis. Below the pics is my brief ID summary and discussion, posted to Cobirds this evening. Click the photos to enlarge. No adjustments have been made except for cropping and compression to make them more web-friendly. The last image has comparison images of Common and Chihuahuan Raven bills superimposed, sized and rotated to match the bird in question.

With valued input from several friends of mine, research into my sound files, and using photo comparisons of raven bills, I believe that they were indeed Chihuahuan Ravens (CHRA). A key point that Tony Leukering brought up was that the bird in the photos was an adult by plumage (lacking any brown aspect in the head), and should therefore have a fully-developed bill (younger ravens retaining the possibility of having bills not fully developed yet and therefore not reliably proportioned.) While the exact position of the nasal bristle tips is obscured by snow on the bird's bill in the photos, I believe that the extent of snow sticking far down the top of the bill suggests the long bristles of CHRA (in fact, the otherwise uniform snow ends with a little lump right about where I would expect CHRA's bristles to extend, much farther down the bill than in Common Raven [CORA].) I admit that this is speculative, though, as the actual bristles can't be seen. More importantly, and not obscured by the snow, is the overall length of the bill and the relatively steeper curve of the leading edge of the culmen (top surface of the bill), which compares nearly perfectly to a reference shot I have of a known CHRA. In the Common Raven (CORA) profile shots I compared, the bills looked distinctly longer and had a more gradual curve on the leading edge of the culmen. All of my respondents shared my regret that the tail wasn't photographed from directly underneath, but the birds didn't cooperate in this area by flying over me. However, in at least one of the shots I feel as though the view isn't inconsistent with CHRA's shorter tail with a flatter trailing edge in comparison to CORA. Finally, while I reiterate my awareness that CORAs can exhibit a wide range of vocalizations, these birds sounded just right for CHRA, further supporting the list of positive CHRA traits I observed in these birds. I've wondered if the blizzards in SE Colorado might push CHRAs out of their "core" range more than normal this winter. It has also occurred to me that the rough conditions down there might instead help them if the predictions of thousands of dead cows (with resultant scavenging opportunities) came true. Of course, we probably don't even have a handle on where the normal distribution of these birds is away from their breeding grounds, as they can be so hard to detect and document in areas frequented by CORAs and American Crows. I wouldn't be at all surprised if they regularly push into the northern Front Range. On a birding trip a couple of summers ago, Doug Faulkner commented to me that they historically ranged into Wyoming following bison herds, so places like Jefferson, Boulder and Larimer Counties shouldn't be a big stretch. Anyway, with other probable CHRA sightings at the Erie Landfill and Valmont Reservoir in the past few weeks, it bears remembering that our big black corvids deserve careful scrutiny, too- something I've usually been guilty of neglecting.

Brrr Brrrds

At the risk of sounding like a broken record, we've continued to have cold, snowy weather in Colorado for the last week. I think we had lows below zero for at least the last four nights here at my home base in Longmont, with the coldest being -14° F my low-registering thermometer marked three nights ago. Today was the first day in a while that we broke into the 20s.
So obviously, most of the water around here is now frozen, making any open water that much more valuable to birds. One interesting place to keep an eye on in Boulder County when things freeze up is the Valmont Reservoir complex, a group of three lakes that provide cooling water for a coal-fired power plant. The return water keeps at least two of the lakes perennially open, attracting hordes of birds whose other options are to leave the area or die. Birds of the big water there include thousands of gulls coming to roost in the evening (7+ species reported so far this winter), all kinds of waterfowl, grebes and cormorants that forgo migration to spend the winter there, and so on. But some water-reliant birds eschew the big lakes.
A couple of days ago, a buddy of mine (Richard Trinkner) reported an accommodating Virginia Rail at a still-open outlet of a small lake near Boulder Reservoir. I investigated yesterday and was delighted to find the bird right above the little culvert draining the otherwise completely frozen, snow covered lake. The little guy ducked into the culvert and soon came out the other side, where it began foraging in the narrow flowing watercourse. It was pretty crazy to see it probing under the overhanging snow on the edges, and to see it run over ice and across snow banks that shortcut to another section of the running water. Eventually I saw it catch a crayfish about as long as its bill, immediately followed by a retreat to the privacy and security of dense cattails to deal with its prey.
In the course of watching this bird I also noticed two companion Wilson's Snipe alternating between imitating reedy growth and probing the soft sediment flooring the waterway.
Of course, wintering Virginia Rails and Wilson's Snipe aren't unheard of around here, but seeing them in in a mid-January snowscape as cross-country skiers swished by behind me was pretty cool.

Saturday, January 13, 2007

California Dreaming- Round 4

Time for one more trip down memory lane and a few more pics from my trip with CFO to Monterey Bay last September (click to read parts 1, 2, and 3.)

So how about some shorebirds? I think that living and birding in Colorado heightens my appreciation of these guys- we get shorebirding opportunities and our share of cool species, but nothing like coastal areas. Often, shorebirds in Colorado are seen at long distances across mudflats of drawn-down water storage reservoirs. While this hones one's skills at shorebird ID, it rarely provides photo opps beyond record shots or study pictures. The mix of good shorebird habitats around Monterey made for some outstanding birding when we weren't out on the boat looking at pelagics. And the birds were often very close- time for some camera work, and not just distant digiscoping! I know I'm in a good situation when I turn off the focus-range limiter on my DSLR lens to shoot within 6 meters, and this happened a lot in California.

Here's a bird that we see regularly in Colorado, but rarely this well- a Western Sandpiper. Kind of an uninspired name though- I'd have named it Flammulated Sandpiper for the fiery racing stripes on the scapulars:

Another bird we have in Colorado (they even breed in the state) are Willets. I've never seen one in breaking surf here, though!

This Semipalmated Plover eventually walked within the focus range of my lens. No biggie- I was happy by then:

The highlights for me, though were west-coast specialties. One such was Black Turnstone- I had seen them before in Washington State, but only had crappy pics of one flying away. The quality of my Black Turnstone photo library abruptly went up at Point Lobos and Point Pinos, where little groups of the accommodating birds posed for me:

My favorite, though, was a Black Oystercatcher at Point Lobos. First, it was a life bird for me. Second, it was a lifer photo bird. Finally, the thing let me sit on a wave-washed rock about 15 feet away while it pried up mollusks at low tide with the light pretty much perfect. Dang- might get my expectations up for every new lifer!! The combo of the orange bill and eye-ring along with the glowing yellow iris set against the dark plumage is stunning to say the least. And look at how stout those pink legs and feet are- gotta be able to hang on in battering waves, I guess.

Friday, January 12, 2007

Birds in the Funnies- Pelican-talkin' Parrot

Wow- a parrot imitating a pelican! Perhaps not the best choice of a wake-up call, though, as Brown Pelicans are generally silent after fledging, and American White Pelicans are generally silent away from breeding grounds and "utters quiet, low grunting or croaking sounds" at nest (per the Sibley Guide to Birds.) (Take a listen at Cornell's Macaulay Library- an amazing resource of nature sounds and videos.)

I'd have gone with the screech-owl, myself- a nice, loud whinny call. BTW, anyone else envious of those who can produce a perfect Eastern Screech-Owl tremolo by fluttering the back of their throat as they whistle? I can only get a weak tremolo at best by building up a gob of saliva back there. Problem is I either whistle well or flutter the gob, but rarely both at the same time. Guess my uvula isn't flapping around enough... My whinny imitation isn't great, either, but I've had birds answer it so I guess that is all that matters...

Monty 1/12/07:

Sunday, January 07, 2007

Bonny birding

From the American Heritage online dictionary:

bon·ny also bon·nie (bŏn'ē)
adj. Scots., -ni·er, -ni·est.
  1. Physically attractive or appealing; pretty.
  2. Excellent.
This definition certainly fits the Bonny (State Park, Colorado) Christmas Bird Count, which I did last Friday, 5 January. Twice postponed by blizzards, we squeezed in the count on the last day of the official counting period despite round 3 (yes, three) of heavy snow in Colorado in the last few weeks. The midnight owling weather was fine, with nearly calm, moonlit conditions (we recorded Eastern Screech, Great Horned, and Long-eared Owls.) The morning portion of the count had pretty steady snow blowing from the north- not very good counting conditions but we prevailed. By lunch it had stopped, and we cleaned up some good birds in the afternoon.

Bonny is known as a great birding area, with riparian woods along the N. Fork of the Republican River, a good-sized lake, and smaller ponds and marshes downstream of the dam. These are surrounded by shortgrass prairie pastures, agricultural fields, farmsteads, ranch headquarters, feedlots, wind breaks, and the hamlet of Idalia, providing a nice variety of habitat within the count circle.

Successive blizzards rendered the lake mostly frozen, but there was open water in the marshy outlet below the dam providing haven for key birds. Walking the productive woods and wind breaks was made difficult by shin-to-thigh deep snow, but new finds were that much more rewarding in the heavy snow cover!

Only five of us survived the attrition of twice re-scheduling and having to count on a weekday. Glenn, the count compiler, did an excellent job of arranging food and lodging at the Colorado Division of Wildlife's Bonny workstation bunkhouse. His potato/sausage/kale soup shored us all up at lunch and gave us the energy to plunge back out into the wintery landscape again for the afternoon session. Prior to that, Paul jump-started us all with French toast- a lot better than the energy bar I was planning on. Alison's salad, bread, and snack treats kept our taste buds happy throughout the day. And Joey's lasagna for the compilation dinner was a fantastic conclusion to the day's menus. (What did I contribute? Mini-marshmallows shot out of a marshmallow gun that Tony gave me in anticipation of duels and shoot-outs while waiting for the midnight hour's owling to begin. But alas, Tony couldn't make the re-scheduled count. Next year...)

The silver lining of the re-schedule was that I got a great jump on my 2007 list. Birds that are tough in most of Colorado but regular at Bonny like Eastern Bluebird and Red-bellied Woodpecker came through as usual. Winter plains birds like Lapland Longspur and Common Redpoll got my attention and appreciation. Turning up unexpected birds is one of the most enjoyable parts of doing a CBC. Our group of three (Glenn, Paul and I) had some real goodies including Brown Thrasher, Mountain Bluebird and Hermit Thrush. But our best bird was a Slate-colored Fox Sparrow. While the race breeds in Colorado, it is only accidental on the Eastern Plains. Throw in the January timing and the bird is especially noteworthy- checking the CBC archives, only one other Slate-colored Fox Sparrow has ever been recorded on a Colorado CBC (of course, a few may have been generically recorded as just "Fox Sparrow", but I'll bet the overwhelming majority are Red Fox sparrows, rare but expected in the winter.) Further underscoring the bird's unexpected status, only one has ever been formally documented in Kansas. (A sliver of the Bonny circle is in that state.) They have been reported a few more times in that state, but it seems like birds need that "full-species" status sometimes to get the attention they deserve.

Thanks again, Glenn, for lining this all up- I'll see everyone out there next time!

Wednesday, January 03, 2007

Birds in the Funnies- Parrots can smell!?!

Another amusing offering from Monty, this time with the ultimate bachelor Moondog doing some dirty laundry with his pet parrot Pilsner (an excellent name, if I do say so myself.) From an ornithological standpoint, though, I don't think that parrots are one of the few bird groups with an acute sense of smell (like vultures and tubenoses.)

Monty 1/3/07: