Sweet Springs Easy Birding plus Oystercatcher Monitoring Update

Sweet Springs Preserve - 9:00 to 10:00 - Heavy moist overcast.  Some people might consider a grey morning rather unpleasant and dull.  For me it was an ideal morning to bird Sweet Springs.  The bay was serene in its stillness.

Shorebirds were racing back and forth across the narrow strip of muddy sand.  Semipalmated Plover were numerous.  These tiny migrant Plovers may have just arrived from their breeding grounds in Alaska.

There were a few Least Sandpiper.  They really are tiny.  Two Greater Yellowleg were focused on probing the sand, while two handsome Black-bellied Plover, in fading breeding plumage, were strolling sedately along the edge of the bay.  I must not forget the Willet, the Marbled Godwit, and dear, faithful Black Phoebe.  A Green Heron flying into the pond area was the highlight of the morning.

      Oystercatcher Monitoring Update

July 29, 2020 - Last photo of the family.  Chicks were nearly a month old.

The last few days of monitoring - July 3 -Parents on duty, one chick visible.  I briefly saw the entire chick moments before taking the photo.

July 7 - Parents on duty, chicks absent.  They could not fly and they could not have wandered far as their rock formation was separate from the other formations.  July 10 - Parents on duty, chicks absent.  One parent flew off, returning with a food morsel clutched in her bill.  She walked down the rock face disappearing into the cracks, sadly emerging with the morsel still clutched in her bill.  I knew in my heart she was searching for her chicks.

What had taken the Oystercatcher chicks?  Was it a raptor?  Was it the sea?  In my estimation, the unforgiving sea had taken the chicks.  Between July 1 and July 6, extremely high tides, combined with a powerful storm surge, had swept them off the rocks.

I have not given up hope.  During the winter months Oystercatchers are often seen feeding along the edge of the surf in Corallina Cove, and I will be there looking for a juvenile with its two-toned bill.

Montaña de Oro - Black Oystercatcher Monitoring Update

Montaña de Oro State Park - Danger Sign Site - Update on Black Oystercatcher (Bloy) monitoring.  Thirty-one days have passed since I began monitoring the Bloy pair at Danger Sign.  The shale formation they are inhabiting is close to the bluff but not connected.  Most of the time, with the exception of very low tides, it is surrounded by water.  Numerous formations that jut into the sea protect the pair's rocky home from the pounding surf.

Beginning May 21, I have monitored the site eight times.  On June 10th, as I neared the site, I could hear alarm calls.  More than likely the pair were chasing off Oystercatcher intruders.  Within a couple of minutes the pair returned.  Neither of them settling onto the nest.  Perhaps there had been a successful hatching.  One of the pair flew off, soon to return with a white morsel clutched in its bright red bill.  A chick appeared for a few moments.  At the same time I thought I might have seen a smidgen of a second chick.  Yeah!!

Two days later I was back.  There were two chicks.  The parents were occupied in full-time provisioning. One was usually standing guard while their mate was off gathering food. 

My last visit was on Friday the 19th. - Two chicks - Parents bringing in the food.  One chick was visible, the other one mostly hidden.  When both parents are foraging both chicks remain out of sight.

In the above photo, this adventuresome little chick is about nine days old.  My next monitoring date is Tuesday the 23rd.  Can hardly wait.

Black Oystercatcher Monitoring

The Black Oystercatcher is considered an indicator species for intertidal health.  They live, feed and breed on rocky, intertidal shorelines that are vulnerable to rising sea levels, human interference, and predators.  Last year, at Montaña de Oro State Park Ca (MdO), only one of nine recorded nesting attempts produced a nestling that grew to maturity.

The Juvenile that grew to maturity is on the left, to the right, the proud parents of Site 7.  Note the two tone bill of the juvenile. (above photo by Gary O'Neill.)

Conservation efforts for Oystercatchers was limited by lack of baseline information.  A study was needed.  MdO nest monitoring began in 2007.  I am familiar with the MdO Oystercatcher population, having learned details on nesting habits from Sara Kelly, an experienced Oystercatcher (bloy) monitor.  I volunteered to be a nest monitor at Site 7. 

During nesting season Bloys are highly territorial, often nesting in the same location as the year before.  The nest may be in a slight depression or in a space between shale layers.  They share all nesting duties including chasing off interlopers.

9:08 am, Thursday May 21 -  My first monitoring experience began at site 7 aka "Danger Sign," on the north side of Quarry Cove.  The sign has been there as long as I have been volunteering at MdO, and that is over two decades.  I greatly doubt anyone has ever heeded the warning.

Monitoring should be done far enough away from the nest site so as not to cause the Bloy to alert.  They may abandon the nest.  Last year symbolic fencing was installed to keep people from disturbing the Bloys.  Do people climb over it?  YES!!

As soon as I arrived I took out my binocs and began monitoring.  I knew the approximate nest location (center of red circle), but only saw slabs of uplifted shale.  I assumed that hidden from view was a Bloy incubating two to three eggs.  While watching what I thought was the nest site, I took quick looks around for the mate.  About 10 minutes into monitoring a Bloy flew to a nearby
rock and began preening.

Since male and female Bloys look alike, I have named them Babbs and Bob.  Babbs was on a rock preening, Bob was hopefully on the nest.  After a few more minutes Bob rose up from a crack to the right of where I had been focused.  Babbs move in and settled down.  Through a crack in the shale I could see a tiny sliver of a bright red bill.  Now I knew where to look.!!  I had just experienced my first nest exchange. ( At the end of the blog is a youtube video of the exchange.)

The morning was beautiful, sunny, no wind.  Now, Bob was preening and Babbs was sitting on the nest.  All of a sudden chaos reigned.  Three raucous Bloy were flying over the next site.  Bob joined them and a moment later Babbs deserted the nest and flew off with the group.  I was in shock.  No one was sitting on the nest.  I felt helpless.  Fortunately, five minutes later Babbs returned to the nest.  Bob was across the cove feeding.  Later I learned this type of behavior is not unusual. 


My first monitoring experience was very interesting.  I do hope that this pair is successful.  At the present time it is the only nesting pair at MdO.
 

You may have to watch the video more than once, but you can see Babbs settle into the nest site.  From now on I will bring a real camera.

https://youtu.be/srqqWdMBgZw