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Thursday, July 31, 2014

Star date: 26 July 2014

If you've been following this blog for a little while, you might remember a story about some Bat Stars (Patiria miniata) that Eric raised last summer and that we followed until they were tiny juvenile sea stars in the fall — review the post from 22 September 2013.

Well, the story didn't end there!  Although very little is known about what juvenile sea stars eat at that stage, Eric kept a few juveniles to observe how they developed.  If you're interested in seeing how they changed, I thought I'd show a few more time points.

The next two pictures were taken in April 2014.  The sea stars didn't grow very much over the winter, so they were still very small and didn't look too different than they did in September.


Here's a close-up of the plates on the upper surface (next image).  Note the overall number of plates, as well as the number of spines extending vertically from them.


By June, they had added a few more plates and a few more spines:


Remarkably, these juvenile Bat Stars really started growing in early summer.  The next series of photos was taken on 26 July 2014.


For comparison, here's a close-up of the plates and spines on the upper surface (below).  Look how many more there are!


And some of you will remember how, with the right lighting, you can see the stomach (pyloric caeca) of juvenile sea stars (for explanation, see post on 23 April 2014).  Two brown lobes extend into each arm of the sea star (for a total of ten lobes).


I know it's hard to visualize just how small these sea stars are.  So here's one more photo with a ruler for scale.  The Bat Stars photographed in July were about 4 mm across.


Wednesday, July 30, 2014

Salmon Creek sphinx


Just a quick shot of a beautiful White-lined Sphinx Moth (Hyles lineata), photographed in Salmon Creek, 29 July 2014.

For more pictures and information about this species, see the Butterflies and Moths of North America and the Moth Photographers Group.

Monday, July 28, 2014

A new mammal for Bodega Head?

Two days ago while at work, I caught a glimpse of a small gray animal gliding over the ground, and I thought to myself, "Huh?"  From that brief view, I would have guessed that it was a ground squirrel, but as far I knew, there were no records of ground squirrels from Bodega Head.  The animal disappeared among some pipes.

I alerted Emily because I knew she walked in that area frequently.  Today she told me that she spotted the animal just before noon (Thanks, Emily!).  I went back to the area and at first was disappointed not to find it.  Then I was drawn to some Barn Swallow scolding and looked closely to see the animal slightly hidden by vegetation.

Once it came out into the open, I got a few decent pictures for the record:



You can see the dappled fur pattern in the next two pictures:



I don't have a lot of experience identifying ground squirrels, but I think this is a California Ground Squirrel (now called Otospermophilus beecheyi).  As far as I know, this is the first time a ground squirrel has been recorded on Bodega Head (but please correct me if I'm wrong).

I've started asking around about the distribution of ground squirrels in Sonoma County.  It sounds like they're rare on the coast.  The Natural History of Ground Squirrels in California by Grinnell and Dixon (1918) says, 

"To the westward they extend within a mile of the seacoast in the vicinity of Eureka and at Cape Mendocino, but elsewhere mostly not closer to the sea than eight or ten miles. Nowhere in the immediate coast belt are they reported especially numerous or injurious."

Here's a map showing ground squirrel distributions from that publication.  Look at the records for "Douglas Ground Squirrel", which is now a subspecies of California Ground Squirrel, in the northwest corner of the state (the open triangle symbols):


Note how few records there are from the Sonoma/Marin coastal areas (in fact, a complete gap is shown in southern Marin County).  The one triangle represented in western Sonoma County is mentioned in the text as "7 miles west of Cazadero."  I plotted that location, and it brings you pretty close to the intersection of Meyers Grade Road and Fort Ross Road (and that's about 3 miles from the coast).

I'd love to hear more about records of ground squirrels in Sonoma and Marin counties, especially near the coast.  I'm sure more records have been added to the map since 1918.  Write to me if you've seen them!

Sunday, July 27, 2014

Southern drifter?

I haven't started with a mystery close-up in a while, so here you go.  Can you guess what type of animal this is?


Here's another perspective (below).  This view is of the underside:


Any guesses yet?  I'll zoom out a bit more and show about half of the animal:


Okay, now here's the entire thing:


Did you guess jellyfish?  This is a Purple-striped Jelly (Chrysaora colorata, formerly Pelagia colorata).

According to the Light & Smith Manual (2007), this species "regularly washes ashore on the beaches of Southern California and is occasionally found as far north as San Francisco and Bodega Bay."

From a distance, when I saw a large jelly washing up on the beach, my first thought was that it was going to be a sea nettle (Chrysaora fuscescens).  Sea nettles are the most common of the large jellies in this area, but they are more brownish overall and lack the dramatic purple stripes of this species.

The bell of this Purple-striped Jelly was ~15-18 inches across.  I didn't have a ruler at the time, but here's a picture with my Xtratuf boot (size 6.5) for scale.


I'm wondering if this Purple-striped Jelly might have drifted north with some of the warm ocean water that we've been experiencing recently?

It looks like there's warm water to our south and offshore.  You can look at sea surface temperature maps at different web sites.  Here are two examples:



 
Have you seen Purple-striped Jellies in Bodega Bay before?  If so, I'd love to hear more about your observations.

Saturday, July 26, 2014

Phocoena phocoena

A few days ago, I was excited to see quite a few Harbor Porpoises (Phocoena phocoena) swimming not too far off of Bodega Head.  Yesterday I was disappointed to hear about this individual that washed up on the beach.  It wasn't alive, so if you're not comfortable viewing pictures of a dead porpoise, you'll want to skip this post.  

These situations have always generated mixed reactions for meI'd rather see the animals alive and well, but it's an opportunity to learn more about a species that we don't get to see up-close very often.

Here are views from above and from the side.  The porpoise was between 5-6 feet long, the maximum length for a Harbor Porpoise.



Whenever I talk about porpoises, the question often comes up about how to tell the difference between a porpoise and a dolphin.

There are a few characteristics that are generally useful (but not always, because of some exceptions) like a blunt snout, rather than a long, pointed snout:


And a short, triangular dorsal fin, rather than a taller, falcate dorsal fin:



But one of the best characteristics (although it's not a great one if you're watching a swimming animal!) is the shape of teeth.  Porpoises have flattened, spade-shaped teeth, while dolphins have sharper, conical teeth:


When ocean conditions are very calm, that's your best chance for seeing Harbor Porpoises.  They're small enough that they don't rise very far above the surface, and they don't generate much of a "blow" when they breathe.  So when the ocean is flat, use binoculars to watch for their small arching backs and triangular dorsal fins.  (I posted a few photos of them in Washington last spring.)

For more information about Harbor Porpoises, check out the OBIS-SEAMAP web page

Tuesday, July 22, 2014

The sound of raindrops...

...in July!

I was a little surprised to hear the sound of raindrops this morning.  I went outside to experience the passing shower, and looked up to see raindrops falling from the sky with the crescent moon in the background:


The sun was high enough that I thought there was a good chance for a rainbow.  I finally spotted a faint arch in the western sky:


The clouds were spectacular.  I couldn't choose just one photo, so here are a few:





Quite a morning for sky watching!

Monday, July 21, 2014

17.5

Today the seawater temperature off Bodega Head reached 17.5°C (63.5°F).  That's one of the warmest temperature readings I've seen since moving here 10 years ago!  It made me look out at the ocean and wonder where that warm water was coming from:


Even far offshore, at the NDBC Bodega Bay buoy, the seawater temperature passed 61°F today.

Sunday, July 20, 2014

Peanuts with chocolate chips

For years I've been trying to photograph this intriguing peanut worm, Themiste pyroides:


I've discussed peanut worms on the blog before (see post from 31 January 2013), but I haven't shown this species yet.

Remember that peanut worm tentacles are located at the tip of a long "introvert" that can be withdrawn, or rolled in on itself.  Here's a series of pictures illustrating that process (below).  Watch the tentacles disappear!
 

Themiste pyroides has wonderful golden tentacles, a purple "neck", and fascinating hooked brown spines — see close-up below.  You'll laugh, but the shape of the spines reminds us of tiny chocolate chips!


Because peanut worms live in crevices, you often only get to see their tentacles.  Look closely for clusters of golden tentacles extending from low intertidal zone crevices along rocky shores, and you may be rewarded with a sighting of Themiste pyroides!

P.S.  In this species, the tentacles are used for suspension feedinggathering small food particles from the water.

Friday, July 18, 2014

Summer sailors

I haven't been able to get out in the field as much recently, so pardon me if I've been missing this event (and please tell me if I have!).

Today I came across some very large By-the-wind Sailors (Velella velella) washing ashore on the beach.


Most of these individuals were 7-8 cm (~3 inches) across at the base of the float see next photo.  [With the mantle extended (the dark blue portion), they measured 10 cm (~4 inches) across.]


Although I submitted a 3-part series about Velella in March, I'm posting these pictures now because it's somewhat unusual to see Velella during the summer...and because I haven't seen Velella this large on Bodega Head in a long time (I think it's been years!).

The local ocean water is extremely warm right now — 62°F (16.7°C).  Perhaps there's a different water mass nearby that's brought a population of Velella near shore at an unusual time of year?

It'll be interesting to see if anything else unusual shows up with this warm ocean water.

P.S.  For more information about Velella velella, see previous posts: December surprise (2012) and Below the water line (2014).

Wednesday, July 16, 2014

Slant of light and shades of gray



Early evening light, photographed from Bodega Head, 16 July 2014

Tuesday, July 15, 2014

Bird of prey



 
I turned the corner when I arrived home, looked up, and was surprised (shocked) to see this Great Horned Owl (Bubo virginianus) sitting on the corner of the building.

It seemed to be actively looking and listening to nearby activity.  And then it focused on something intently.  I'm glad it wasn't me.

Sunday, July 13, 2014

Master of disguise

After field work this morning, Eric's sharp eyes spotted something interesting below a boulder:


It might be hard to identify at first, but did you find the small octopus in the center of the image?  It's camouflaged like a rock.  The overall color of the octopus is brown, somewhat different than the rest of its surroundings. And if you look closely, you can see the two eyes outlined in white. 

We decided to watch this octopus for a little while, and we're so glad that we did.  Here's what happened next:

The octopus left the ledge and moved into a patch of coralline algae:


In the picture above, the octopus (the same one) is in the center of the image.  It's so well camouflaged, this time like the algae, that it might be challenging to see.  Below is a closeup to help you find the octopus and to help you appreciate the wonders of its disguisethe colors, the patterns, and the textures.  Notice how pointy it is, just like the upright branches of the algae!


Then the octopus moved to the edge of the coralline algae and started transforming again:

 
It morphed into an amazing combination — the head and mantle looked like the pale, blotchy tunicates (sea squirts) in the background, while the arms looked like the darker purplish-red algae nearby.

 
Is it a rock, algae, or a tunicate?  What a master of disguise!

Thursday, July 10, 2014

"All wing"


Spot-winged Glider (Pantala hymenaea), washed up on the beach on 9 July 2014.  I'm now used to seeing these dragonflies show up at this time of year (see previous posts from 2012 and 2013).  

Unfortunately, this individual didn't make it.  It's hard to know what happened for sure.  Perhaps it flew too far out to sea and didn't have enough energy to make it back to land?  Or if it tried to land on something floating on the ocean surface, could it have been caught by an unexpected wave and unable to free itself from the water?

I learned a fun fact about the genus name tonight.  According to the Wikipedia entry, Pantala means "all wing."  When you take a moment to look at the surface area of the wings, you can see why this name was given to them.

In New England, Wandering Gliders (Pantala flavescens) are generally more common than Spot-winged Gliders (Pantala hymenaea).  In fact, Wandering Gliders are one of the most widely distributed dragonflies in the world, while Spot-winged Gliders are restricted to North and South America.

In California, however, there are more records for Spot-winged Gliders than Wandering Gliders.  You can review basic maps of their distributions here:


It's interesting to think about why Spot-winged Gliders might be more common than Wandering Gliders in California.  Or is this just my bias being focused along the northern California coast?