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Sunday, May 31, 2015

Under the bridge


Do you have any guesses about which species of bird made this nest? 

Here's a perfect description of the nest:

"Their adherent nests are composed of a mud shell lined with plant fibers, typically placed over water and plastered to a vertical wall within a few centimeters of a protective ceiling."


Did you guess swallow?  If so, that's a good guess...but note that the nestlings in the picture above are black and they have fairly large bills, unlike swallows.  Note that finding the bills (yellowish/pinkish in color) is the easiest way to count the nestlings.  (There appear to be at least three nestlings, and perhaps more if some are hidden.)


Warning: The next picture will reveal the owner of the nest.



This adult Black Phoebe (Sayornis nigricans) had just caught a fly and was preparing to bring it to these nestlings.

Here are a few fun facts about Black Phoebe breeding behavior:

- It takes 1-3 weeks for the female to build the nest
- Building a nest close to a "protective ceiling" may help to discourage avian predators
- Clutch size varies between 1-6, with a mean of 4
- The female incubates the eggs for ~16 days
- Both parents feed the young in the nest for ~18 days
- Nestlings are primarily fed bees/wasps, flies, and butterflies/moths
- After leaving the nest, the young will stay with the parents for another 7-10 days

These pictures were taken near Falletti Park in Cotati on 31 May 2015.

P.S.  Facts above from The Birds of North America account by B.O. Wolf.

Saturday, May 30, 2015

Thinking of Rafe

 Pacific Grove, 7 April 2007 


Red Octopus (Octopus rubescens)


We're still in shock over the tragic loss of Rafe SagarinOur hearts go out to his family.  Today we thought about places and things that Rafe loved and shared.  There is so much we'll miss about Rafe, especially his great kindness, creativity, and passion for natural history.

Thursday, May 28, 2015

Back in Blue

They're back!  Last summer and fall we encountered these barnacles for the first time.  There have been so many By-the-wind Sailors (Velella velella) washing up recently that we wondered if the barnacles might appear again.  Tonight we spotted at least 2 dozen Blue Buoy Barnacles (Dosima fascicularis) on Salmon Creek Beach.


I wrote about Blue Buoy Barnacles last year, so I'll refer you to those posts to learn more about this fascinating species (see below):




And here are a few more pictures from 28 May 2015.

We noticed a few differences this spring compared to last summer/fall, some of which might have to do with the time of year.

Some of these barnacles were on Velella that were fairly complete, while last year the barnacles were attached to only small pieces of Velella and many of the barnacles had made their own floats.



Here's one that was starting to produce its float material the white foamy mass at the base of the blue stalk:



Some of the Blue Buoy Barnacles we encountered tonight were quite small.  The largest were 15 mm long (the length of the plates that enclose the body, not including the stalk), while the smallest were only ~5 mm long.


We don't know how long these wonderful, pelagic blue barnacles will be visible in this area, but it's worth watching for them if you're walking local beaches.  Let me know if you find some!


P.S.  Don't miss this video featuring Blue Buoy Barnacles:


Wednesday, May 27, 2015

Enjoying the flowers


Well, these pictures don't do this bird justice, but because Baltimore Orioles (Icterus glabula) are rare in Sonoma County (there are only ~7 records), and because this is the first one I've seen on Bodega Head, it seemed worthwhile to post a couple of pictures.

And, if you're interested in seeing this bird, it might still be possible.  It seemed drawn to the eucalyptus flowers (see below), so perhaps it will stick around for a little while.


Photographed in Owl Canyon on 27 May 2015.

P.S.  Madrone Audubon has a map showing Owl Canyon.  And Colin Talcroft has provided an aerial view with a written description.

Tuesday, May 26, 2015

Loping along


A nice set of early morning tracks, loping along towards the water's edge.

Do you have any guesses about what type of animal made these tracks?

I'll zoom in on one set of tracks for some additional clues.  Each track was ~3-3.5 inches (7.5-9 cm) wide and ~3-4 inches (7.5-10 cm) long .


This is a little tricky because the entire foot didn't register on the relatively hard-packed sand.  The uppermost print is probably the best.  Note that it has 5 toes, with short claws.  And the innermost toe is set lower than the others.

Here's a different set, at a slightly different angle.  Warning: The answer will be below this picture.



Okay — my best guess is that these tracks were made by a River Otter (Lontra canadensis).  Although the webbing doesn't show, everything else looks good for an otter the habitat, the size, the toe patterns, and the loping stride.

I was curious about whether the individual feet could be identified.  If you want to try this, remember that the front feet are smaller and more symmetrical, while the hind feet are larger and asymmetrical because the inner toe is slightly below the other four.

Here's the first close-up again.  Which is the right front, left front, right hind, and left hind?



Below is my best guess for the individual feet.  If you have a different answer, let me know!


Although we don't get to see River Otters very often, it's fun to see their tracks and to think about them exploring the shorelines of Bodega Bay!

Monday, May 25, 2015

Be still my...

It's been quite a week for molluscs, especially nudibranchs and sea hares.  Here's another special nudibranch — special because it's beautiful, because it's different than many other local nudibranchs (I'll explain), and because it's rare north of San Francisco.  It may be another species that's present in northern California this year because of warm water conditions during the past year.


Meet Hancockia californica.  This individual was spotted at Coleman Beach on 23 May 2015.  It was ~15 mm long.

I mentioned Hancockia is different than many other nudibranchs.  This is true in several ways, one of which includes the shape of the cerata (the upright projections on its back).  The cerata are palmate each is made up of 4-16 finger-like processes in a U-shaped cluster.

The illustrations of Hancockia in MacFarland's 1923 paper makes this easier to see:



From MacFarland, F.M.  1923.  The morphology of the nudibranch genus Hancockia.  Journal of Morphology 38: 65-104.  (Those page numbers are correct this is an extensive article!)


Now that you know what to look for, here's a close-up of these unusual cerata:



When reading MacFarland's article, I was glad to see a couple of other things mentioned that stood out to us when watching this nudibranch.

In MacFarland's words, Hancockia has a "prominent cardiac elevation."  Translation: the position of its heart stands out because of a raised bump on its back this bump was so "elevated" that it looked like a small bubble.  In the picture below, it's the rounded area with squiggly red lines:


MacFarland also commented on Hancockia's unusual way of moving:

"In captivity it is at first very active, continually creeping around the sides of the aquarium and upon algae by a method entirely different from the smooth gliding movement of other Nudibranchs. The anterior third of the body, i.e. the portion in front of the heart region and the second pair of cerata, is stretched forward to its full extent, the anterior end of the foot and the lip region are closely applied to the surface and adhere tightly while the rest of the body is pulled forward, a distance of 1 or 2 mm at a time, the posterior end of the body taking but little active part in the process."

Translation: Hancockia moves like an inchworm!  

Here's a short video clip so you can see (1) the beating heart, (2) the obvious ridge zigzagging down its back ("vascular ramifications to the cerata" = basically a raised conduit bringing blood from the heart to the cerata), (3) the unusual palmate cerata, and (4) a hint of the inchworm-like movement:




P.S.  If you were wondering, the genus Hancockia was named after the English naturalist Albany Hancock, co-author and primary illustrator of "A Monograph of the British Nudibranchiate Mollusca: with Figures of All the Species" published in eight parts by The Ray Society between 1845-1855.

Sunday, May 24, 2015

Skin deep

Okay, are you ready for a mystery close-up?


Although it's tricky, there's a clue near the bottom of the image above.

Here's a slightly different region:



And now I'm going to zoom in on the "clue" (below):


Any guesses?

The clue shown above is a barnacle.  And perhaps you can tell that it's embedded in the skin of a mammal.  So now you have to think about what type of marine mammal would have barnacles living on it?

The picture below provides the answer:


This Gray Whale (Eschrichtius robustus) washed up on the southern end of Portuguese Beach on 23 May 2015.  It was ~31 feet long.

Being a big fan of barnacles, I took a few minutes to research the identity of this species.  It turns out that there are some really interesting facts about it.

The barnacle is Cryptolepas rachianecti.  It only grows on Gray Whales!  The scientific name alludes to that fact, if you know that Gray Whales used to be called Rhachianectis glaucus.  The genus, Cryptolepas, basically means "hidden barnacle" I'm assuming it refers to how most of this barnacle is hidden below the whale's skin.  See illustration below:

From Pilsbry, H.A.  1916.  The Sessile Barnacles (Cirripedia) contained in the Collections of the U.S. National Museum; Including a Monograph of the American Species.  Bulletin of the U.S. National Museum (No. 93).


Here's a picture of what Cryptolepas looks like when you can see all of its plates because it's no longer embedded in the whale's skin (view from above on left, view from below on right):

From Pilsbry, H.A.  1916.  The Sessile Barnacles (Cirripedia) contained in the Collections of the U.S. National Museum; Including a Monograph of the American Species.  Bulletin of the U.S. National Museum (No. 93). 


Because very small barnacles (2-5 mm across) are seen on north-bound whales (there are some in the skin pictures above), it's thought that Cryptolepas reproduces while the whales are in Baja.  This makes sense for the barnacle, since aggregations of whales would make it easier for the swimming barnacle larvae to find hosts.

And Newman (in Intertidal Invertebrates of California, 1980) suggests that the position of the barnacles being flush with the surface of the whale's skin is "a valuable adaptation, since gray whales have been noted to rub against objects on the sea floor and near shore."

 Quite a tale from a barnacle and a whale!



P.S.  Scientists from the California Academy of Sciences think this whale was attacked by Orcas.

Saturday, May 23, 2015

Munching at Miwok


Do you recognize this animal?  The picture above is a head-on close-up.

Here's a view from the side (a different individual):


Note the two rolled rhinophores (sense organs) sticking up, and the two flap-like oral tentacles extending forward.  The overall coloration is also distinctive blotches of red, brown, green and gold...and a network of dark lines (reminiscent of the crackle of raku pottery!).

Here's an entire animal viewed from the side:


This is a California Sea Hare (Aplysia californica).  We had heard that some had been observed at Miwok Beach (along the Sonoma Coast just north of Bodega Bay), so we stopped there this morning to take a look.

California Sea Hares are rare in northern California.  It's likely their presence here this year is due to the warmer water temperatures during the past year.

Although it's hard to tell from the pictures, they're quite large!  The maximum recorded size is ~75 cm (30 inches) long, and up to 15 lbs (7 kg).  Most are smaller, but still substantial.  The individuals we documented today were ~20-25 cm long.  Here's a picture with my boot for scale (this sea hare had been stranded out of water at low tide, but was just waiting for the tide to return):


Why are they called sea hares?  Well, if you return to the first picture of this post, you might be able to see a resemblance between this snail and a hare because of the way the rhinophores look like the tall ears of a hare.  And similar to rabbits, sea hares are herbivores in this case, grazing on a variety of seaweeds and sometimes seagrass.  Also, although it's probably not related to their name, sea hares move fairly fast relative to other snails.  [If you're wondering, sea hares are gastropods a group of molluscs that includes snails, limpets, nudibranchs, and sea hares.]

There were at least 50, and perhaps as many as 100 or so, California Sea Hares at Miwok Beach today.  It's not a species we see in this area very often, so if you find them this year, I'd love to hear about it!


P.S.  I've heard of reports of California Sea Hares in Tomales Bay this year, but I'm not sure of the exact locations.

Thursday, May 21, 2015

albus & cocoa

After field work today, Eric spotted a couple of nice nudibranchs.  It was a fun combination of species, named after two contrasting colors.


The first was a White Dendronotus (Dendronotus albus).  The standout feature of this species are the cerata (dorsal projections) on the back — "delicately branched" and tipped with white and orange. 




The second species was a Chocolate Cuthona (Cuthona cocoachroma).  Note that the centers of the cerata are chocolate brown.  The frosted white tips of the cerata are also distinctive.

Both of these nudibranchs were feeding on hydroids in tidepools in the low intertidal zone. 

Wednesday, May 20, 2015

Towel, anyone?

We found a very large blade of red algae washed up on the beach a couple of days ago:


Although it might be hard to tell from the picture, this algae is known for its texture it's covered with small bumps or spines.  They're dense, which gives the seaweed a rough texture.  Because of this, someone came up with a distinctive name for it — Turkish Towel.  

This is Chondracanthus.  (My guess is Chondracanthus corymbiferus.)  However, Turkish Towel is often easier to remember!

This towel was so big (you might call it a bath sheet!), Eric thought he'd give it a try:


There are over 200 species of seaweeds in the Bodega Bay region.  I'll be trying to highlight more of them this year.

Tuesday, May 19, 2015

Fiery and flamboyant

One of the goals of this blog is to introduce you to animals that you might not be aware of.  Because of that, some of the species I've highlighted are inconspicuous, small, or hard to see.  That is not the case with this species.


Another goal of this blog is to record observations that are unusual.  This species falls into that category.

Meet the Spanish Shawl (Flabellina iodinea) a flamboyant nudibranch that's much more common in southern California.  They have been found from the Galapagos Islands to British Columbia, but they're rare north of San Francisco.  And in fact, there are no records for Oregon, and there's only one record for Washington.  (Thanks to Jeff Goddard for this information.)

Below is a close-up of the anterior end, showing off the amazing colors: blue tentacles, red rhinophores (sense organs), orange cerata (projections on the back), purple body.



Here's a picture of the cerata.  Because they're in clusters and are of varying lengths, they remind me of flames.



Spanish Shawls are known for their swimming abilities.  To move among sites, or to escape predators, they swim with dramatic U-shaped undulations flexing one way and then the other, and repeating this over and over again.  I captured one sequence to give you a feel for this motion:


Eric spotted one individual (~5 cm long) at Pinnacle Gulch on 18 May 2015.  Then Jason discovered another small individual on 19 May 2015.  Because they're so rare in this region (this is the first time we've seen them in Bodega Bay), we also took some close-ups of the smaller one for documentation: 



It's hard to believe this very tropical-looking nudibranch found its way to northern California!

If you see any Spanish Shawls during your coastal adventures, I'd love to hear about it and it would be great to compile sightings in northern California.
 

Monday, May 18, 2015

Blue ribbon

Okay, do you remember the mystery photos from last night?


Some of you might have noticed in the Comments section that Matt won the prize he guessed correctly that these patches are dense concentrations of pelagic barnacle cyprids.  Recall that cyprids are the final larval stage that settles out of the plankton.  In this case, these are the cyprids of a pelagic gooseneck barnacle called Lepas sp. 

Here's a close-up of the cyprids under a microscope:


After settling on a floating substrate, the cyprids will undergo metamorphosis into juvenile barnacles.  A few of them had already done so:


I wanted to post these pictures on the blog because there have been amazing numbers of Lepas cyprids this year more than any other year since I've been observing floating objects washing ashore in Bodega Bay.  I've wondered if it could be related to the warm water temperatures last year, but we can't be certain.

What's perhaps even more fun, though, is that when I went to take these documentary pictures, I noticed a few other things among the cyprids!


At first I thought this was just a blue tentacle (perhaps from Velella)...but then it started moving...and then I noticed the eye spots at the anterior (front) end.  A tiny blue ribbon worm!  I'd never seen a blue ribbon worm before.

One time the ribbon worm left one patch of cyprids and crossed the great divide to another patch of cyprids.  If anyone has thoughts about the identity of this ribbon worm, I'd love to hear more.



When I was scanning the cyprids, I also noticed quite a few small light brown spots.  If you look very carefully, you'll see them in the lower left corner of the next photo, nestled among the cyprids:


When I zoomed in, I could see that these brown spots were moving, that they had dark eyespots, and that they might have some sort of paired structures forming on their heads (see small bumps in image below).


Although I'm uncertain, my best guess for these little brown blobs is that they could be very young pelagic nudibranchs (Fiona pinnata).  I've written about Fiona before (see post on 19 October 2012), but I've never seen one this small, hence my uncertainty.  What do you think?  Do you have a different guess?

The Sea Palm and Lepas cyprids reminded us of a valuable lesson it's always worth taking a closer look!