What Was That?

Rock wren (Salpinctes obsoletus) at the pig pen.

My current theme: "Don't be shy, go ahead and ask an expert."  But do your homework first.

In August while admiring the lacy cudweed pillows behind the barn, I noticed a bird hopping in the speckled light of the pig pen.  It was a plain-looking bird, just another LBJ (little brown job), except it had a distinct way of flitting from one object to the next.

The bird had a long, curved bill, and was cinnamon-brown on its upper back and grey-blue with dark flecks on its lower back.  This pattern didn't match any of the birds I usually see in the yard: junco, black phoebe, California quail, Stellar jay, scrub jay, acorn woodpecker, house finch, western bluebird, brown towhee, ash-throated flycatcher, band-tailed pigeon and certainly not turkey vulture.  And it didn't match the occasional visitors such as yellow-rumped warbler, Say's phoebe, American robin, northern flicker, red-breasted sapsucker, and so on.  I went to get my binoculars.

The barn provides the rock wren flying insects and spiders to eat and a place to hide.

On closer inspection, grey down showed through the mussed-up feathers on its light-colored unstreaked breast, so I guessed it might either be a juvenile or a molting adult.  This time of year, the exhausted bird parents have finished raising one or two broods and many are molting into new feathers for their annual fall migration.  The young birds have left the nest and should have learned to fly and to feed themselves.  Some juveniles are the dull-colored birds hanging out in big flocks, while others are left to fend for themselves.  I went to find my field notebook to sketch the bird.

My first thought was maybe it was a cuckoo.  Years ago, a juvenile yellow-billed cuckoo visited a phenomenally successful riparian restoration site I helped plant along Coyote Creek in San Jose.  Cuckoos like riparian forests but are rarely seen in this area, so we took it as a good sign that our restoration work was heading in the right direction.  I hadn't seen a yellow-billed cuckoo since, I just remembered it had a curved bill and some type of wedged pattern to its long tail.  I went to get my camera, rushed to get the 200 mm lens mounted and grabbed my tripod on the way out the kitchen door.

The bird was still inspecting the pig shed.  As I approached slowly, it came out to meet me.  It seemed curious.  It was bobbing up and down and turning its head sidewise towards me.  I crept forward and took lots of photos.  After awhile, the bird flew from the pig pen to a bulldozer parked next to the barn.  We played hide and seek round and round the dozer.  Then it hopscotched across the gravel in front of the barn as I peered around the red corner.  After an hour of entertaining each other, it was getting dark and I lost sight of my new friend.

Top view of rock wren tail.

I went inside and poured through the bird books.  The bird was rather plain, and if it was a juvenile, the characteristic markings of the species might not be obvious yet.  I flipped between books and my photos and sketches, feeling that familiar frustration with LBJs.  Then I noticed in one of my photos, the bird had a distinct black fan above the brown corners of its closed tail.  I flipped back through the landbird pages of The Sibley Guide to Birds, checking every tail.  The rock wren on page 391 showed a spread tail with a similar pattern, and the bird was described as bouncing up and down in deep knee bends.

I had never seen a rock wren before, so I checked the range and habitat descriptions.  Rock wrens have a broad range in western states with their habitat listed as rock outcrops.  There are no rock outcrops near the Dipper farmyard.  I queried the seasonal barcharts at the eBird website to see how often and when rock wrens have been reported in San Mateo County.  The reports were few and limited to the coastal part of the county:  a single rock wren once in October 1999, once in December 2008, and four times in February 2009.  Rock wrens have been more frequently seen breeding inland at nearby Santa Clara County.  Was this an unusual sighting or was I just fooling myself?  I turned to Facebook.  I posted a few of the photos and asked a birding friend to check.  She enthusiastically confirmed it was a rock wren.

The rock wren inspects a pile of metal debris with many crevices much like rock piles.

Over the next few days, I chatted about the rock wren to just about everyone I met, and the rock wren greeted me most evenings next to the barn.  A co-worker encouraged me to post the sighting and photos on Peninsula Birds - a Yahoo group where local birders share their unusual bird sightings in the San Francisco Peninsula.  I lurk on Pen Birds to see what unusual birds are showing up in our area and to keep in touch with the migratory season.  With the Curly Birder's encouragement, I posted the sighting on Pen Birds, and asked for confirmation on the identification and for more information on rock wrens in San Mateo County.

I was delighted to quickly receive responses from several experts of our local bird world who confirmed that my visitor was a rock wren, possibly a juvenile that had dispersed from the rocky cliffs of Devil's Canyon which is about a mile away from the Dipper Ranch (as the wren flies), and this was the first reported sighting of a rock wren in San Mateo County in a couple of years.  A birding friend (and hopefully a future guest writer for this blog) came by and we spent an hour watching the rock wren catch dusk-flying insects.  Amusingly, when the wren caught a large insect, it ducked under the barn door as if to consume its prize in private.

This juvenile rock wren is now on its own and appears to have successfully learned to feed itself.  It is probably trying to find its own territory with food and shelter and eventually a mate.

So, don't be shy, ask an expert and you might find yourself relaxing and sitting in front of the barn in a camp chair at sunset with three cameras.  You are not allowed to be lazy, though.  At least look up some initial information and keep good notes of your observations.  Then you will be able to provide a better description to someone who was not an eyewitness.  I admit to being annoyed when someone asks me to identify a plant like this: "What was the yellow flower I saw at Los Trancos Open Space Preserve?"  There are hundreds of local yellow flowers.  Details are important.  Photos are helpful but sometimes sketches show detail even better.

Having recently gotten so much help identifying this bird, I intend to be more patient the next time someone asks me to identify a plant.  And tonight, I will finally start a Links page to the Dipper Ranch blog.  I haven't taken the time before, but geez, we are talking about experts and homework, right?  First, I will post tonight's bird sources, and over time, I expect to list more links, other natural history bloggers and cite books I commonly refer to when seeking information about natural resources of the Santa Cruz Mountains.  Come back and check it out.