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Monday, September 30, 2013

Day 79

The little octopus embryos continue to develop.  These pictures were taken yesterday, Day 79.  Their chromatophores are extremely active now.  Here are two pictures taken within seconds of each other.  Note the dramatic change in size of many of the chromatophores, especially the ones just behind the eyes:



While Kristin and Carol were taking care of the octopus last week, they noticed that the ink sacs are now visible.  In the next image, look for the small black angular spot within the mantle (see white arrow).


In the image above, you can also see the octopus' arms grasping what's remaining of the external yolk — a small white ball at the end of the capsule.  We don't know exactly how many days are left before they hatch, but we're still estimating sometime within the next few weeks.


 

Sunday, September 29, 2013

Resting among the Ruppia

I haven't had a chance to post these images, so here are a few from Salmon Creek on 14 September:

Red-necked Phalarope (Phalaropus lobatus) resting among Ditch-grass or Wigeon Grass (Ruppia maritima).  Can you spot the flies on the surface of the water?


Every now and then, the phalaropes would wake up, reach out, and snatch up a nearby fly.  In the picture above, the phalarope's bill reminds me of chopsticks as it delicately holds a fly.


Landscape photo, showing a phalarope using a piece of driftwood as a wind shelter.  Can you spot the phalarope?  

It's just to the left of the largest piece of driftwood in the center of the photo.  There were at least 4 phalaropes in this area that day, and each one chose a different piece of wood to shelter behind.

Friday, September 27, 2013

Fiddler on the sand


Sand Fiddler Crab (Uca pugilator) in Chatham, MA

Fiddler crabs are known for their "waving displays" when courting females — a male waves its oversized claw while standing near its burrow entrance.  Although this male crab isn't waving its large left claw, it seemed appropriate to discuss this topic as we're waving goodbye to New England and returning to California tomorrow.  We wish the two coasts weren't so far apart!

Thursday, September 26, 2013

A day at the beach

Just a few photo highlights from a walk on South Beach in Chatham, Massachusetts, on 25 September 2013.  In order of appearance:

 Palm Warbler (Setophaga palmarum)



Wandering Glider (Pantala flavescens)



Tiger beetle, possibly a Hairy-necked Tiger Beetle (Cicindela sp., possibly Cicindela hirticollis).  [I don't have access to a field guide at the moment!  I'll correct this if I learn otherwise.]



Peregrine Falcon (Falco peregrinus) with avian prey (and trailing a dried eelgrass blade).



Gray Seal (Halichoerus grypus)



Very large unidentified ray actively feeding in shallow water near shore.  This ray was at least 4-5 feet across!  That's one tip of a pectoral fin raised above the surface.  The white coloration below the water is the ventral surface exposed whenever the ray pivoted.



Horned Larks (Eremophila alpestris)



It was a beautiful day at the beach!

Wednesday, September 25, 2013

A shocking discovery


We were walking along the inside of South Beach in Chatham today and discovered this unusual animal washed up on the sand.  You can see that it had the attention of both Eric and a young gull!

Here's a closer view from the side:


This is an Atlantic Torpedo Ray (Torpedo nobiliana).  I remembered that they sometimes strand on Cape Cod beaches in the fall, but I'm not sure if anyone has figured out why.  This individual was about 4 feet long.

Note the very circular shape and the relatively straight front edge of the disc.  The tail is short and the caudal fin (tail fin) is large and paddle-shaped (see below).


Torpedo rays are sometimes called electric rays.  They have electric organs that produce powerful electric shocks that stun their prey (primarily fish).

I found a couple of good fact sheets about Atlantic Torpedo Rays online.  If you're interested in learning more about them, check out the FLMNH Ichthyology Department web site or this page from The Shark Trust.

Tuesday, September 24, 2013

Traveling day

Today was mostly a traveling day, but below are a few images from brief stops here and there along the way:

 Close-up of Common Green Darner (Anax junius) in Walpole, MA



A wonderful jumping spider with bright emerald green palps!  The next picture shows the same spider from above.  These were taken in North Eastham, MA.


Sunset over Cape Cod Bay

Monday, September 23, 2013

Fall migrants


We’re in New England visiting family and friends and have been lucky to catch up with a few flocks of migrant songbirds.  How I miss warbler migration on the East Coast! 

I didn’t end up with great shots, but here are a few for the record and to remember the experience.  We found at least 12 species of warblers in just a couple of very small flocks near the house where we’re staying in southern New Hampshire.  Beautiful!

Black-and-white Warbler (Mniotilta varia)


Black-throated Green Warbler (Setophaga virens)


Chestnut-sided Warbler (Setophaga pensylvanica)


Blue-headed Vireo (Vireo solitarius)


And the 12 species of warblers?  Yellow Warbler, Chestnut-sided Warbler, Magnolia Warbler, Black-throated Blue Warbler, Yellow-rumped Warbler, Black-throated Green Warbler, Bay-breasted Warbler, Blackpoll Warbler, Pine Warbler, Black-and-white Warbler, American Redstart, and Common Yellowthroat.

Sunday, September 22, 2013

Star date: 14 September 2013

Are some of you wondering what happened to the little Bat Stars (Patiria miniata) that Eric raised in the lab?  (If you don't know about this story, you can read about it in the post on 12 August 2013.)  

Well, they've continued to do well, and they've grown quite a bit.  We photographed the Bat Stars again about one month after they went through metamorphosis from the larval stage.  Here are two pictures taken on 14 September 2013.

The first image shows the beautiful spines, giving the little sea star a snowflake-like appearance.  And notice the tubefeet reaching out from below.



The second image highlights the ossicles on the uppermost surface of the sea star.  The ossicles are calcified plates embedded within connective tissue.  They're the skeleton of the sea star.  In the picture below, the ossicles look like little floating puzzle pieces that are perforated.  (Although blurry, you may also be able to see that there are tall spines growing out of the ossicles.)


In these small Bat Stars, the ossicles look remarkably similar to those of a sea cucumber.  Review the post on 16 April 2013 to compare!

Friday, September 20, 2013

Ay, Corambe!

A couple of weeks ago, Eric noticed some Giant Kelp blades (Macrocystis pyrifera) washed ashore on the outer beach.  They had large patches of bryozoan colonies (Membranipora sp.), and when he looked closely, he spotted a tiny egg mass on one of the colonies.  We thought it might belong to a nudibranch, so we brought the kelp blade into the lab and did a quick visual inspection, but we couldn't find a nudibranch at the time.

We decided to put the kelp blade in a tank with seawater to look at again later.  I hadn't had a chance to do so until yesterday.  I wasn't really that hopeful, so I was surprised to see new egg masses when I picked up the kelp blade this time (see below)!


The egg mass is the crescent-shaped gelatinous object filled with tiny developing embryos.  It's attached to the bryozoan colony.  A few of the bryozoans are out and feeding to the left of the egg mass.

Discovering new egg masses was a good sign, so I started scanning the bryozoan colony with my hand lens and I'm guessing you know what happened next.  I found one!  This nudibranch is incredibly well camouflaged against the bryozoan colony (see next image).



Meet Corambe steinbergae (formerly Doridella steinbergae)!  Note that it's mostly transparent except for the fine white lines that mimic the skeletal structure of the bryozoan.  There are also small red-brown splotches do they blend in with the background of the kelp? 

Here's another picture with a different individual that's a little easier to see.  These nudibranchs are tiny, I'm guessing 5 mm or less in length.


Eventually I found one that had crawled part way on to the kelp (next image).  Look for the smooth rhinophores at the anterior (head) end near the bottom of the picture.  (This feature separates them from a similar species, Corambe pacifica).


Corambe steinbergae and Membranipora have been the subject of classic research on inducible defenses.  The nudibranchs eat the bryozoans. [I read that they can eat up to 150 zooids per day!  Zooids are the members of the bryozoan colony — they are visible as rectangular units in the photographs above.]  To defend themselves, the uneaten portions of the bryozoan colony respond by growing significant spines which make it harder for the nudibranch to access the remaining zooids.  The bryozoan can grow spines in response to the nudibranch within as little as 2 days!

Thursday, September 19, 2013

Inversion!

As many of you know, we're continuing to follow the development of some Red Octopus embryos.  Here's a picture from Day 64.  Note the much smaller size of the yolk (the opaque white tip of the capsule), and the much greater number of chromatophores.


While tracking their development, we've been consulting Steven Osborn's master's thesis — Fecundity and embryonic development of Octopus rubescens Berry from Monterey Bay, California.  In one section, Steven wrote, "Embryos reverse their position twice during development...The first inversion occurred at Stage 17-18.  The second inversion occurred at Stage 29-30."

We were too late to see the first inversion (we didn't start watching until about Stage 19).  But we knew the second inversion was due.  When I looked at the embryos today (Day 69), I was a little surprised to see that many of them had inverted overnight!  The easiest way to see this is to look at the position of the eyes and whether they're closer to the broad, rounded end of the capsule (as above)...or closer to the narrow, pointed end (as with many of the embryos below).


Wow!


Now I'm nervous.  I'll be away for a week, and luckily we have good octopus-sitters.  But hatching might not be too far away!  We were estimating it would happen sometime in October (and it still might), but if water temperatures have been warm, development may be faster.

P.S.  For those who haven't seen them, previous posts about these octopus include Day 52 and Day 36.

Wednesday, September 18, 2013

Am I in Mexico?

Early this morning I saw a Blue-footed Booby fly by Bodega Head, and then later this afternoon some beachwalkers alerted us to the presence of this animal stranded on Salmon Creek Beach:


With the exception of Leatherback Turtles which have a more northerly distribution and are observed swimming and feeding offshore in this area occasionally, most other sea turtle sightings in this part of California are rare and involve dead stranded animals.

I think the turtle in this photograph is an Olive Ridley Sea Turtle (Lepidochelys olivacea).  It's carapace was ~62 cm long.  Although I'm not completely familiar with their status in this region, it sounds like there have been at least 4 local records since the late 1980s: one at McClure's Beach on Point Reyes in January 1987, one offshore of Marin County in October 2001, one in Tomales Bay in November 2002, and one at Stinson Beach in November 2009.

There's a short article about central California sightings in this Marine Turtle Newsletter.  And more general information about Olive Ridleys is available on this National Marine Fisheries Service web page.

If you happen to find a stranded sea turtle, it's best not to move it, but to contact stranding experts at either the California Academy of Sciences (415-379-5381) or The Marine Mammal Center (415-289-7350).

Tuesday, September 17, 2013

Blue-footed!

The last major influx of Blue-footed Boobies (Sula nebouxii) along the California coast was in 1972.  (Most of them nest in the tropics, e.g., on the Galapagos Islands and in the Gulf of California).  Since 11 September 2013, multiple sightings have occurred from southern California to Point Reyes, with a flurry of observations during the past weekend.  

Early this morning Alan Wight and Dan Nelson spotted the first Blue-footed Boobies ever recorded in Sonoma County!  The boobies flew by the bluffs near the outer parking lot on the southern end of Bodega Head.  I've heard that both Alan and Dan managed to get photographs.  Congratulations to both of them for having the foresight to be watching for boobies from Bodega Head this morning!

Dan has kindly permitted me to post a couple of his images here to share this exciting record.


These are juvenile birds, with darker heads and duller feet than adults.  But you can still see a hint of blue on the feet in the close-up below.


ADDENDUM (18 September 2013): Click here to see some of Alan's pictures.


P.S.  I was curious about the species name, "nebouxii."  According to the Dictionary of American Bird Names, it's after Dr. Adolphe Simon Neboux: "Little is known about Neboux except that he was Surgeon Major on the French exploring vessel Venus, which visited the coast of California in the course of a cruise extending from 1836 to 1839.  The Blue-footed Booby named in his honor in 1882 by Milne-Edwards, the eminent French Zoologist, was possibly based on a specimen collected on the Venus expedition."

Monday, September 16, 2013

Fluttering down the road

So I was walking along the side of Westshore Road on Sunday when a large pale green insect came flying or fluttering down the middle of the road at about eye level.  My brow furrowed in puzzlement, but luckily the insect veered and landed in the vegetation a few feet in front of me.


I'm trying to remember back over the past 9 years, but I think this is the first praying mantis I've seen on Bodega Head.  I have a vague memory of talking about them and their status in California, but I can't recall observing one locally.  Has anyone else seen them on Bodega Head?  I'm wondering how common (or uncommon) they are here.

It sounds like there are a few species of mantids in California, so I'm not sure yet which species this is, but I'll ask around to try to find out.

There's an interesting thing going on in these pictures.  Did you notice that one antenna is bent over in a loop (see above, and close-up below)?


I'm wondering if the mantis is cleaning its antenna by drawing it through its mouthparts.  Or do you have other ideas about what's happening?

Here's another view:


Let me know if you have other local praying mantis stories!


P.S.  Annie Dillard writes about watching praying mantis in Pilgrim at Tinker Creek, one of my early inspirations in making natural history observations.

Sunday, September 15, 2013

With flare

Driving in to work around mid-day today, at about the same time Eric and I both said, "What was that?" as a bird flew in front of the car and landed on a nearby shrub.  Eric noticed yellow underneath and I observed white on the outer tail feathers.  We stopped the car and got out to see if we could locate the mystery bird.  We found two of them!  

I snapped a quick, distant photo, but then the birds flew off towards Owl Canyon.  I decided to take a short walk to see if I could find them again for a better look.  

At first I didn't think I was going to relocate them, but then I saw them flying back towards the entrance to the marine lab.  And then Mike and David drove by.  They stopped, I told them about the birds, and we drove back to look for them.  Luckily, they were easy to find and this time I managed a couple of photos for the record.  A team effort paid off!



Western Kingbirds (Tyrannus verticalis) are rare migrants on Bodega Head.  They're more common at inland sites in Sonoma County, but are uncommon along the coast.  Western Kingbirds are neotropical migrants — after nesting in southern Canada and the U.S., they'll spend the winter primarily in southern Mexico and Central America.

Later in the day I encountered one of the kingbirds in a different location exhibiting an interesting behavior (see below).


This is a wonderful position because it shows off an important field mark for Western Kingbirds.  Take a look at the outermost tail feathers.  Note that the outer edge (or web) is white.  The Birds of North America account provides a good description of the behavior in this photo: "suns with body spread flat, neck extended, wings spread out, and tail flared."

You might want to compare these Western Kingbird images to the Tropical Kingbird pictures that I posted last year.  For example, compare the length and thickness of the bill, the color of the upper breast, and the color of the back.  (I don't have a great photo of a Tropical Kingbird tail, but note that they lack the white edges to the outer tail feathers.) Sightings of both species are possible at this time of year.

Saturday, September 14, 2013

Wading in the shallows

Thanks to a tip from the North Bay Birds e-mail group, I took a short walk near the mouth of Salmon Creek this afternoon to look for some Red-necked Phalaropes that were reported there yesterday.  I found a few phalaropes (more about them later), but I also came across another species that I hadn't seen in a while:


This is a Long-billed Dowitcher (Limnodromus scolopaceus).  Although the name would make you think the length of the bill is the most important feature, there's quite a bit of overlap between Long-billed and Short-billed dowitchers.  One of the best ways to separate the two species is by their calls.  This one did vocalize, confirming the i.d., but I didn't record it, so we'll talk about another good character that you can see in these pictures.

In this case it's helpful to look at two particular groups of feathers. Juvenile Long-billed Dowitchers have very plainly marked tertials and greater wing coverts — they're mostly gray with pale edges.  In juvenile Short-billed Dowitchers, these same feathers would be highly patterned with strong rusty internal bars or stripes.  To help see the tertials and greater wing coverts, I've labeled them below:


This bird was wading in the shallows and feeding along the shoreline of Salmon Creek, probing deeply with its bill.



I like the lighting in the next image.  (That's a Least Sandpiper on the left.)


Although Long-billed Dowitchers are less common than Short-billed Dowitchers in this area, this is a good time of year to find them, so keep an eye out.

Friday, September 13, 2013

Brace yourself...


...and do it with friends!


Black-bellied Plovers (Pluvialis squatarola) and Short-billed Dowitchers (Limnodromus griseus) brace themselves against 20 knot winds and blowing sand at Doran Beach on 13 September 2013.  [The plovers are in the center and at the far left; the dowitchers are in the foreground.]

Black-bellied Plovers are gray or silver in non-breeding plumage (see below).  The individual in the center of the picture above is in transition.