If you're interested in using any of these photographs, please contact me. Send an e-mail to naturalhistoryphotos(at)gmail.com. Thanks!

Friday, July 31, 2015

Feeding frenzy

During the last five days or so, some sort of bait fish has been concentrated just offshore of Bodega Head.  Joe mentioned there have been large schools of juvenile herring near the harbor entrance, so perhaps they're also along the outer coast?

The numbers of seabirds feeding on them have been impressive, although hard to capture in pictures.  Here's an example of one view from 27 July 2015, with gulls, terns, cormorants, pelicans, and probably a few murres.  [On this day, I think there were more murres offshore of Bodega Head than I've ever seen (or heard) before.]


And today the birds were joined by a few Humpback Whales (Megaptera novaeanglieae).  Note the knobby dorsal fin.



If the bait fish stick around this weekend, it could be a good time to catch a seabird and mammal show! 

P.S. For a few more Humpback pictures, and some tips about how to tell them apart from Gray Whales, see the post from 1 November 2012.
 

Thursday, July 30, 2015

Let's spend the night together

We pulled into the driveway after work, and I noticed a small, pale butterfly perched up high on a flower:


I took a few quick pictures, and then we went inside.  I did a few chores, and then I went outside again and the butterfly was in the same position.  Here's a view in slightly different light:


Without my books, it's harder to identify things.  I searched on the Internet, and I'm guessing this is a Common Checkered-Skipper (Pyrgus communis), but let me know if you think it's something different.

While scanning pictures and information about Common Checkered-Skippers, I ran across this description from butterfliesandmoths.org: "Adults roost exposed on a tall plant beginning in late afternoon." 

This meant that the butterfly might spend the night in that location.  So I went out again after dark, and it was still there!

I liked this head-on view:


Perched on a flower seems like a nice way to spend the night!

Tuesday, July 28, 2015

Wondering about winter


I've been reading Barbarian Days: A Surfing Life by William Finnegan, so I've been thinking about waves a lot. 

Tonight I dove back into "the archives" and randomly chose a few wave photos to share, all taken along the Sonoma Coast.



Who knows what this winter will bring?  :)
 

Monday, July 27, 2015

Picasso en la playa?


The waves painted a Picasso on Salmon Creek Beach!

Photographed 27 July 2015 
 

Sunday, July 26, 2015

Close


The raven chicks are getting close to fledging now.  This photo was taken on 20 July 2015 when the four nestlings were ~5 weeks old.  Perhaps they'll start to fly this week or next?  

(To track their progress, review previous posts on 26 June 2015 and 8 July 2015.)

P.S.  Two of the Bottlenose Dolphins I posted about on 13 July 2015 have been identified!  Check out the new information in the addendum here.

Saturday, July 25, 2015

Junior sailor


After abundant Velella observations this spring, there's been a lull in sightings recently.  Today we spotted 8-10 Velella on Salmon Creek Beach.  They ranged in size from ~12-25 mm long.  

The wind is predicted to be even stronger tomorrow, so perhaps a few more will wash ashore on local beaches.

P.S.  Have you heard they've been catching Dorado, or Mahi-mahi (Coryphaena hippurus) off Fort Bragg?  Amazing!

Thursday, July 23, 2015

Island of activity



I haven't shown a picture of Bodega Rock in a while.  This picture was taken from the southern end of Bodega Head on 18 July 2015.  There was lots of sea lion and cormorant activity.  You might be able to spot some pelicans, too.  I wished I had had my audio recorder, as I could hear a Wandering Tattler over there!

Wednesday, July 22, 2015

Summer wave


Off Bodega Head, 20 July 2015

Tuesday, July 21, 2015

Working on wings to fly

A few days ago, Kate and her crew noticed an intriguing animal in their plankton sample.


We could tell that it was snail veliger (larva), but we weren't certain about the species.

In between broad wings, it had a very pretty shell:


A tapering foot was visible below:


The veliger had large velar lobes and the lobes were edged with bright orange polka dots.  With active bundles of cilia, it was using the velar lobes to swim.  (This is best viewed in the video at the end of this post.)


As mentioned, we weren't familiar with this snail, so we started sending pictures around for help.  No one responded right away, so Eric decided to keep it in the lab for a few days. 

A couple of days later, the veliger had undergone metamorphosis into a juvenile snail!  This made it much easier to identify.


Note that the ciliated velar lobes are gone; the orange and gold speckles have expanded; and there are two siphons the anterior one (to the left) is formed by a flap near the front end, and the back one (to the right) is formed by the folding of the wings.  (In this case, the wings are extensions of the foot.)  Water is pulled into the front siphon, passes over the gill, and then is expelled out the back siphon.

As the snail glided along and explored its environment, we occasionally caught a glimpse of its two dark eyes:


Pacific Stomach Wings (Gastropteron pacificum) are capable of crawling and swimming.

Eric was fortunate to have filmed this snail when it was still a larva (swimming with its velar lobes) and after it metamorphosed into a juvenile.

Check out his video below!  (Click on the title of the video to see a high resolution version.)



Many thanks to Kate and her team for sharing this wonderful find from the plankton off Bodega Head!
 
P.S.  If any gastropod enthusiasts out there are wondering Pacific Stomach Wings are cephalaspideans, related to headshield slugs and bubble snails.

Sunday, July 19, 2015

Do a little dance

On 4 July 2015, I mentioned that Red Saddlebags (Tramea onusta) are showing up in Northern California this year.  The weather this weekend — warm temperatures, southerly winds — created potential for more of these dragonflies to move north along the coast. 

I went out for a short time this afternoon (19 July 2015) to look for them.  I saw at least seven Red Saddlebags, and four of those were male-female pairs.  And they were ovipositing (egg-laying)!

Here's one of my better pictures of a pair in tandem (below), with the male on the left and the female on the right.  The male clasps the female's head with special appendages at the end of his abdomen.  (And in this case, the female is holding onto the male's abdomen with her legs.)


The next steps (assuming they've already mated) are really fun to watch.  When ovipositing, Red Saddlebags "do a little dance."  

The female produces a small cluster of eggs at the tip of her abdomen (the yellowish blob):



Then the male releases the female:



She drops to the water's surface to deposit the eggs (tapping the water with the tip of her abdomen), while he hovers above her:



Then he immediately clasps her again:



And they start all over:


Watching this today, I wondered how the male knows when to release the female to deposit the eggs? 

This is a special year to watch for this southern species in Northern California.  (And if you're in Oregon, you have a chance for a state record!)  While at freshwater ponds, keep your eyes open for these flying jewels.
 

Saturday, July 18, 2015

Little ones


Gray Fox (Urocyon cinereoargenteus) pups, 18 July 2015.

Note the grizzled upperparts; cinnamon neck, sides, and legs; and the black-tipped tail.


Litter size in Gray Foxes ranges from 1-7, with a mean of 3.8  When the pups are ~3 months old, they'll forage away from the den site with their parents.  At ~4 months, they'll hunt independently.

For pictures of an adult, see the post from 10 September 2012.


Facts above from Fritzell, E.K. and K.J. Haroldson.  1982.  Mammalian Species No. 189, Urocyon cinereoargenteus.  The American Society of Mammalogists.

Thursday, July 16, 2015

Screech!

I stepped out of my car last night and heard a very loud screech.

I turned towards the sound and saw this:


The sound gave away this juvenile Great Horned Owl the screech is a begging call.

But there are a few other characteristics that help identify it as a juvenile.  Can you see them?  The next image will make it easier.


The are still downy feathers on most of the head.  They're the ones that look short and fluffy.  And the "ear tufts" aren't fully developed yet.

Here's an adult (that was sitting nearby) for contrast:


There were at least two juveniles in this eucalyptus grove.  I was impressed with their screeching, and with the size of their feet!

If you're interested, here's a very short recording of the screech:
   

Wednesday, July 15, 2015

The Von Wentletrap Family

Not too long ago, I mentioned I'd try to post more pictures of local snails.  Back in June 2012, I shared some pictures of Tinted Wentletraps (Epitonium tinctum).  Well, here's "the other wentletrap" that is, a different species of wentletrap (Family Epitoniidae), but one that may also be observed on Bodega Head.


Although this shell had washed up on the beach, Boreal Wentletraps (Opalia wroblewskyi, formerly Opalia borealis, formerly Opalia chacei) are often associated with their prey Giant Green Anemones (Anthopleura xanthogrammica).

Here's another view, this time from below:


Boreal Wentletraps reach a maximum size of ~35 mm long, so keep an eye open for these beautiful turreted shells.

P.S.  There's a bonus snail in these photos.  Near the top edge, there are two very small reddish-brown snails.  They're actually adult snails (that's about as big a they get!).  Say hello to Barleeia haliotiphila.
 

Monday, July 13, 2015

Through the fog

There was dense fog and light drizzle on 9 July 2015, but visibility was good enough for spotting a small pod of Bottlenose Dolphins (Tursiops truncatus) swimming by Bodega Head:


I caught five individuals in one picture (above), but I'm guessing there were at least 6, and perhaps more, in the group.

Here's a close-up of two with distinctive dorsal fins:


Perhaps folks with the Golden Gate Cetacean Research group will be able to identify these individuals.

ADDENDUM (26 July 2015): Thanks to Bill Keener (with GGCR), the two individuals in the lower picture have been identified:

"The first dolphin [on the left] is "Miss" and she is an well-known older female in fact her records go all the way back to 1982 when she was first observed in San Diego, and she has also been spotted in Santa Barbara, Monterey Bay and San Francisco Bay. So she could be nearly 50 years old!  The second dolphin [on the right], "Willow" is a male that has been seen in Monterey Bay, and we have seen him down along the San Mateo coast."

Sunday, July 12, 2015

Evasive...

...maneuvers!


A Western Sandpiper (Calidris mauri) trying to avoid the talons of a Peregrine Falcon (Falco peregrinus).  (It worked!)  Photographed 11 July 2015 at Salmon Creek Beach.

Earlier in the day I watched a large flock of Western Sandpipers flying over the tidal flats in Bodega Harbor.  You can see why they stick together!


Saturday, July 11, 2015

Laser light show

Are you ready for a light show?


Emily and Kate found this amazing larva in a plankton tow off Bodega Head on 9 July 2015.  

All of these pictures (and video) were taken through a microscope:


This is the planktonic larva of a marine worm (Family Oweniidae).  It's an unusual larva, and it has an unusual name it's called a mitraria.

The following is a simple illustration to help visualize the major parts.  There is a cap-like portion called the episphere (note that a ciliated band runs along its perimeter and in the species shown here, four segments of the band have orange pigment).  The cluster of long setae (bristles) really stands out.


Modified from Smith, D.L. and K.B. Johnson, 1996.  A guide to marine coastal plankton and marine invertebrate larvae, 2nd ed.  Kendall Hunt Publishing, Dubuque, Iowa. 


We think there's something about the structure of the setae that causes light to be reflected in various colors (mostly blue and green, with occasional orange).  



When a mitraria larve is disturbed, or threatened (e.g., by a predator), it spreads its setae wide in a radiating pattern, perhaps as a defensive strategy (to make it less palatable).


Although the pictures give you some idea about the wonderful color patterns created by the setae, there's nothing like seeing this "light show" in video form.  

Watch, and wonder!

(Click on the title of the video to see a high resolution version highly recommended!) 



Thanks to Emily and Kate for sharing this wonderful larva with us...and with you!
 

Friday, July 10, 2015

Ripples

 
Pacific Loon (Gavia pacifica), Bodega Harbor, 8 July 2015

Thursday, July 9, 2015

Rebound

Can you guess what this is?


Today I was walking by a pool, noticed rain drops on the surface, and thought it might be fun to photograph them to document the rain showers on 9 July 2015.


When I checked the pictures to see if the lighting looked okay, I noticed something interesting:  I had caught some rebounding droplets on film!

The first image above is a clear example.  I looked through more pictures, and found several other examples of this phenomenon.

Most of the droplets represented complete rebounds i.e., the droplets were free of the surface.  How many rebounding droplets can you spot in the image below?


I think there are four rebounding droplets three that are very easy to see, and a fourth very small droplet near the top edge of the picture. 

Later I tried to learn about drop impact dynamics.  It's fascinating to think about the complexity of this interaction.  When a droplet hits the surface, four basic results are possible: splashing, spreading, receding, or bouncing.  The factors that influence the results include things like the properties of the droplet (e.g., its size and density), the surface tension of the liquid that the droplet is hitting, and the impact velocity.

Sometimes a column of water is sent up from the impact zone and sometimes a droplet forms at the top of the column (see below).  The column of water is called a "Worthington jet."  If the droplet remains attached to the jet, it's termed a "partial rebound."  If the droplet is sent upward and breaks free from the jet, it's called a "complete rebound."

(Below, I'm not sure if the droplet broke free after I took the picture, but I'm guessing it did.)


It was so nice to see some rain, especially in July during a drought.  And then there was the additional bonus of a foray into drop impact dynamics.  Perhaps these photos will also inspire you to explore and wonder about the fate of rain drops!


P.S.  Some of the facts above are from Yarin, A.L.  2006.  Drop impact dynamics: Splashing, spreading, receding, bouncing...Annu. Rev. Fluid Mech. 38: 159-192.

Wednesday, July 8, 2015

Semi-gloss

Remember the "Gargoyles by the sea" from 26 June 2015?  I went back to check on them, so here's an update:


All four raven chicks appear to be doing well.  They've grown quite a bit in the 12 days between these visits.  The chicks are now ~3.5 weeks old.  


I'm guessing they probably have a couple more weeks in the nest.  After fledging, they'll stay in the area for at least a few weeks, still being fed by the parents. 

It's fun to see their glossy feathers, and the development of classic raven postures and behaviors.