Friday, April 29, 2011

Wild, Wild Life

Black-headed grosbeaks are now singing in the Valley, there were more orioles on Thursday's birdwalk, and several dozen yellow-rumps encountered in 3 flocks -a tiny portion of them singing. Three Vaux's swifts patrolled over the Valley Visitor Center. Hummingbirds are doing display flights. About a month ago NPS volunteer interpreter Kirsten discovered a rare Virginia Rail near the boardwalk in Cook's Meadow.
On the mammal side, a dark brown bear has been grazing the Ahwahnee Meadow area lately. Two rescue helicopters there on Tuesday night didn't disturb its feeding. Biologists researching our fisher populations are delighted to have encountered a mother with young, moving them from place to place in the south area of the park. Good news for predators and general food web health; bad news for mice and squirrels.
Road crews are grinding away at the extra-deep snow on both Glacier Point and Tioga Roads, slowly making progress to open up the high country for our cars. Tomorrow morning might be cold enough for frazil production, but then it warms up for the early part of the week. There is still a chance for big frazil flows for another few weeks; just because April's over doesn't mean that we won't have some sub-freezing nights in Yosemite Valley.

Monday, April 25, 2011

Slow spring

Too warm for frazil ice, too cool for rapid snowmelt, our recent unsettled weather continues this week with a bit of cloudy damp. The weather forecast leads us to anticipate no frazil ice this week.
Black oak leaves are not quite starting to burst out of buds yet, though they have lower down. Cottonwood flowers are out along the river. Insectivorous orioles are in the Valley now, ahead of most insect food. Redwings are singing in Cook's Meadow, mallards swim in pairs, yellow-rumped warblers sing a bit on sunny days.
Former Yosemite employee Paul Keel, back for a visit, added a new species to the park's birdlist: our first ever white-faced ibis. Paul is a state park ranger now, down on the coast, and he got good photos of the ibis in El Capitan Meadow. You never know what you'll come across, if you're paying attention.
This morning we watched a male belted kingfisher working the oxbow lake in Cook's Meadow. Fun to see a fish predator well away from the river channel.
More predators will be on display in the Conservancy's "Hawks and Owls" field seminar the first weekend of June. Park ornithologist Sarah Stock and great grey owl specialist Joe Medley (yes, the son of Steve Medley) are the two instructors. We are delighted to have these two knowledgeable experts (and charming individuals) teaching this fun program. There's still space available; free camping and free park entry are part of the package. Raptors rule the skies...

Wednesday, April 20, 2011

National Parks Week

I am back in Yosemite after two weeks away, and what changes there are. The free entrance to Yosemite for National Parks Week, combined with some school spring breaks has meant a busy week in the park. The natural scene is busy, too.
Snow is gone from the Valley floor except in a few shady spots. Waterfalls are bigger than average, with the recent warmth getting a start on melting off our exceptional snowpack. Cooks, Leidig, El Capitan, Stoneman, Ahwahnee and Slaughterhouse (lovely, I know) Meadows all have standing and/or running water in them now; some paths are blocked, but none of the main ones yet. Table Rock, our local visual river gauge for Valley commuters, is underwater.
Frazil ice forecast for this weekend: POOR.
Yellow-rumped warblers are at their brightest in the black oak canopies, where tiny pink leaves are barely starting to emerge in the Valley. Black-throated gray warblers are doing their excited, buzzy call in the live oaks in the Valley now, too. A great gray owl was reported on its nest up near Crane Flat, though there's so much snow there still, their food is out of reach and it's hard to imagine successful breeding at this point.
Our "Moonbow Photography" Outdoor Adventures course was a success on Sunday night, with a bright bow visible for a couple hours in-between overcast periods. Next up is Ken Rockwell and Dave Wyman's "Spring Light Photography" course, and then an excellent "Hawks and Owls" program the first weekend of June.
Our regular public birdwalk will be seeking John Muir's favorite bird tomorrow, Cinclus mexicanus. Thursday is his 173rd birthday. Friday is Earth's birthday; stand up for what you stand on, as they say.

Friday, April 1, 2011

Yosemite Recovered

The storm of 20-21 March goes into the record books as one of the most significant in decades: over 12 feet of snow at the 7-8000' level, and 9 inches of heavy snow that broke down thousands of live oaks and other trees at the 2000' level. Electricity was restored after 6 days, and visitation has now picked up.
We've had very warm weather the past few days. Bird activity has increased, flowers are on the rebound, and the Merced River has doubled in volume and is really turbid. The river has gone over 1500 cfs at Pohono Bridge, more than twice the average flow for this date. Sierra-wide snow surveys show 165% of normal water content in the snowpack; our local results come out shortly and will surely be comparably abundant.
We all look ahead to the waterfall season of the next 3 months, hoping that all this snow runs off over a long span of summer, rather than all at once. Photographers Ken Rockwell and Dave Wyman have timed their "Spring Light Photography" course to coincide with predicted high volume, 19-22 May.
We're also coming into peak frazil season this month. The frazil ice forecast is poor for the next few days, as temperatures are mild. But the warmth makes more mist, which will produce more frazil particles when the temperature does drop again.
I'll be away from the park the next two weeks.