Chone

 

A few days ago, I was trying to photograph this beautiful tubeworm under a microscope.  This is Chone sp. (probably Chone minuta), commonly found among surfgrass in the rocky intertidal zone.

When you first encounter them in the field, you might mistake these worms for mats of accumulated shells and sand.  But when you inspect this material closely, you can see that it's made up of many densely packed individual worm tubes that are covered with small shell fragments.  I need a better picture, but this is what they look like at the base of the surfgrass when the tide is out:

 

The worms use their feather-like tentacles for feeding.  While I was looking at them under the microscope, something on the left side of the tentacles caught my eye.  Can you see the horseshoe-shaped piece at about 9 o'clock in the image below?

 

I wasn't sure what it was, so I started searching to see if it showed up in other places (next image).

 

Sure enough, those horseshoe-shape pieces extended between each tentacle.  I didn't know it before that moment, but Chone has webbing between its tentacles!  

Below is a view from the side.  You can see how the transparent webbing forms a membrane below the tips of the tentacles to the opening of the tube.

 

I'm not sure what function this webbing serves, but it has been suggested for another species (Myxicola) with a similar structure that it prevents fine sediment from being drawn up from below and fouling the feeding tentacles.

One more fun and somewhat puzzling observation about Chone.  Sometimes they would pull in their tentacles, leaving only the tips projecting outward at the edge of the tube (see below). 

 

I started calling this the "sun position" because they looked like little suns when they did this. While in this position, the tentacle tips flicked regularly in random sequence.  I don't know what's going on with this behavior, but it was interesting to watch and to wonder about!

Scurfy

 

While looking at Beach Saltbush (Atriplex leucophylla) this afternoon, Peter noticed the striking red-and-white stems. You can barely see them against the sand in the photo above, but here's a close-up in the next image.

 

We realized we hadn't really paid much attention to the stems before.  When I got home, I wanted to see if the stems were mentioned in species descriptions.  Several accounts discuss how this shrub is scurfy (a botanical term for having a scaly covering or coating), but interestingly, the red coloration often doesn't come up.

Out of curiosity, I checked some older photos for the red color and to see if they were scurfy.  It was intriguing to see that the scurfiness varied.  At times it was quite dense and the stems were almost white (next image).

 

But other times there was almost no scurfiness and the stems were bright red (see below). 

 

I don't have a large sample size, but in general the least amount of scurfiness on the stems seemed to be present in the winter and early spring.  Do the reddest stems represent new growth?  Or are they stems that have been uncovered by sand recently?  Or is it related to something else?

If you're interested in looking at Beach Saltbush yourself, watch for it growing along the uppermost portion of local beaches.

P.S.  Scurfy.  It's a strange word, isn't it?  Because this plant is so scurfy, or scaly, another common name for it, according to Calflora, is Sea Scale.

Cloaked in mystery

Well, sometimes I just can't help it.  I'm from the Boston area, and the Bruins made me proud tonight (although I did feel bad for the Penguins; that was a tough loss!).  So I tried to think of the last photograph I took that had black and gold highlights.  This is what I came up with:

 

I photographed this Mourning Cloak butterfly (Nymphalis antiopa) on San Juan Island in Washington on 25 May 2013.

Mourning Cloaks are often associated with willows, and sure enough, we found several of them basking in the sun near a willow thicket.  A few were also sipping sap from the bark (next image).

 

Note that the undersides of their wings are very different than the uppersides — predominantly black and charcoal gray with a golden border.

 

There are quite a few willow thickets on Bodega Head and I've often thought those sites would be good places to find Mourning Cloaks.  I haven't found one yet, and it's actually been a bit of a mystery why I haven't seen Mourning Cloaks locally.  Are they just not common along the Sonoma Coast?  

But recently, in A Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Regions, I read a reference to Mourning Cloaks undergoing a "catastrophic regional population collapse, disappearing from many places and becoming very rare in others."  And it sounds like this may have happened in the early 2000s.  So now I'm wondering if I arrived in this area at a time when Mourning Cloaks are harder to find...or if they've always been rare (or unrecorded) on Bodega Head?  If you are familiar with their status in this area, I'd love to hear more!

 

500!

 

This photo was taken in January 2011, but it's the closest I could come to finding a picture that represented an exclamation point.  This is the 500th post on the Natural History of Bodega Head!  Whew!  

Thanks so much for tuning in during the last year and half and for all of your enthusiasm for natural history!  I'm grateful for your company on this journey to explore and learn more about the local inhabitants and the processes that shape Bodega Head.

Singing from the willows

I haven't been able to share any sounds from Bodega Head recently, so here's an audio recording from Campbell Cove this past weekend.  [Remember, if you're reading this in an e-mail, click on the title of the post above to go to the website to access the audio files.  You might need to turn up your volume.]

I never saw this bird, but it was singing from just inside the edge of the willows.

swth song1 by nhbh


The Birds of North America account for Swainson's Thrush (Catharus ustulatus) starts this way: "This secretive denizen of forests and woodlands across the northern portion of the continent is perhaps best known by its flutelike, upwardly spiraling song that lingers well into the fading summer twilight."  Here's another example of its song:

swth song4 by nhbh


And now that you've heard the thrush's song a couple of times, below is a third recording with a variety of other species singing nearby.  Especially noticeable is a Wilson's Warbler calling and singing towards the end of the recording (there's a single warbler call note at 19 seconds and a song at 24 seconds).
  swth song2 by nhbh


Just before I left the area, the Swainson's Thrush started giving a loud, down-slurred call note.  I scrambled to get the recorder out again and was lucky to capture a few notes (next file).  Listen for four call notes, and then the thrush starts to sing again. 
  swth calls by nhbh


In general, bird songs are usually longer and more complex and used to advertise territories or attract mates; calls are shorter and simpler and used to maintain contact or express alarm (or sometimes the function is unknown).

Although even more common in forested areas further inland, it's nice that a few Swainson's Thrushes sing from some of the shady, wooded sites on Bodega Head.
 

The unexpected

There are lots of things to like about walking beaches, but one of the most enjoyable is encountering the unexpected.  While walking Salmon Creek Beach this afternoon, I started seeing beetles washed up in the wrack line.  And not just a few beetles, but thousands of beetles!  It was pretty phenomenal.
 
Most of the beetles looked like this (see next image).  It might be a Spotted Cucumber Beetle, but I don't have much experience identifying this type of beetle, so please let me know if you are familiar with this species.

 

When I started looking more closely, I realized there were other species involved.  There were quite a few ladybugs, or ladybird beetles (see below for one example).  And a smaller beetle with mottled orange and brown markings (also in the image below).

 

And a wonderful weevil:

 

And there were true bugs, too!  Check out this intense metallic green bug:

 

And a bright orange stink bug (upside down, with wings open):

 

 And a treehopper with a rounded red horn (placed on a Bull Kelp float for a photo)!

 

And then I was more than surprised to see a backswimmer washed ashore!  They're normally in freshwater ponds, but they can fly, so it must have been caught offshore and then washed in by the waves.

 

And then this water strider, too!

 

Okay, I think you're getting the idea that there were a lot of insects washed up on the beach today.  I'm just showing a few of them, but there were also bees, wasps, flies, butterflies, moths, and more.  

I'm not quite sure what happened to all of these animals.  Perhaps they were dispersing during the warm weather, drifted too far offshore, then got caught in the strong winds during the past couple of days, blown onto the surface of the ocean and then washed up onto the beach.  Do you have other ideas?

Warm enough

Bodega Head can be a tough place for butterflies — it's often cool, foggy, and windy.  But this morning it was relatively warm, sunny, and still.  So I decided to go for a quick walk near Campbell Cove to see what I could find.  I was rewarded with six species of butterflies.  Here's one of them.

 

This is a Satyr Anglewing (Polygonia satyrus).  I first wrote about them last May when we saw one during a walk at Point Reyes (read that story here), but these are the first pictures I've posted of this species from Bodega Head.  

Satyr Anglewings are often associated with Stinging Nettles, and so far that holds true for the places I've seen this species on Bodega Head (Campbell Cove and Owl Canyon).

Note the dramatic angles along the edges of the wings:

 

Although a beautiful orange above, Satyr Anglewings are mostly brown below (see next photo).  When their wings are held upright, their shape and subtle coloration probably helps them look like a dried leaf or a piece of bark. 

 

I encountered two different anglewings during my walk.  The second one appeared to be sipping water from a monkeyflower plant (see below). 

 

It was interesting that the white hindwing mark on this individual was a slightly different shape — it was much more hook-like (next image).  All of the characteristics still point to this being a Satyr Anglewing, but it's a good example of how individuals can vary within a species.

 

P.S.  For the record, the other species of butterflies recorded at Campbell Cove today included Acmon Blue, Echo Blue, Cabbage White, Mylitta Crescent, and Red Admiral.