Hauling in the net

 

A few years ago, I was excited to write about one of our local tube snails, Petaloconchus montereyensis.  (You can review that post from 11 June 2012).  

I mentioned that Petaloconchus produces mucus nets to capture food particles from the water.  Well, just last month, Eric caught some of their feeding behavior in a short video.

Before watching the video, it will be helpful to remember a few things:

Petaloconchus has two sets of tentacles: the cephalic tentacles are larger, darker, closer to the edge of the shell, and near their base, have a black spot, which is the eye.  The pedal tentacles are smaller, paler, and closer to the operculum (the round "trap-door").  Look for both types of tentacles in the photo below and in the video.  (The pedal tentacles help guide the mucus nets when feeding.)

 

To feed, Petaloconchus spreads a large mucus net into the water for capturing drifting particles.  Then they use their radula (tongue-like organ lined with rows of shiny teeth) to grasp the mucus net and haul it back into the mouth using a very rhythmic motion.  This is one of the behaviors highlighted in the video.

vermetid feeding sanford from Jackie Sones on Vimeo.

These tube snails are relatively small — the largest tube openings are ~2 mm across — so Eric filmed them under a microscope.  Otherwise, it wouldn't be easy to observe this behavior and to watch these fascinating snails in action.  Thanks, Eric!

Just starting

 

Surfbird (Aphriza virgata), Bodega Bay, 16 March 2015

I wrote about molting Surfbirds a couple of years ago, but I can't help posting another picture tonight.  I missed seeing Surfbirds this winter— there didn't seem to be many around on Bodega Head for some reason.

I encountered a flock near Pinnacle Gulch today and it felt good to see them.  I zoomed in on this one.  If you look closely, you can see a few new feathers just starting to come in.  [Click on the picture for a larger version.]  Most of the older feathers are brown and worn, with tattered edges.  The new feathers have dark gray centers and clean edges.  You can review the post from 25 March 2013 for other examples.

It was interesting to compare the molt timing in these two years.  It seemed like the birds in 2013 were farther along, and the date of those pictures is only about one week away this year.  I'm not sure what drives the start of their molt in this area — do you know?

Patterns

 

Neat patterns on the water today.  The ocean was very calm, with southwest winds at ~5 mph.

When I went to look at the ocean, I noticed a pair of ravens on the bluff, one of which was gathering nesting material.  I love the patterns made by their feathers:

 

Among the leaves and flowers

 

I had fun learning about Nuttall's Woodpeckers (Picoides nuttallii) today, 14 March 2015.  

I know some of you are familiar with this species, and some of you aren't.  If you have spent time with the similar Downy Woodpecker, some notable differences in Nuttall's include:

- black-and-white barring extending across the back (Downy's have a vertical white stripe)

- an extensive red patch on the back of the male's head (a male Downy's patch is smaller)

- some black spotting on the underparts (Downy's have none)

 

I watched this male Nuttall's Woodpecker foraging in an oak in Santa Rosa.  It spent most of its time among the new leaves and flowers.  I hadn't really watched a woodpecker do that before, so when I returned home, I read more about Nuttall's Woodpeckers and their feeding behavior.

It's true that Nuttall's Woodpeckers like oaks — especially Live Oaks, Valley Oaks, and Blue Oaks.

But it turns out that they're known for being different — i.e., they don't often peck wood vigorously and forage deep below the bark like many other woodpeckers.  Instead they tap gently from the side, probe near the surface, and glean from the surface itself.  Miller and Bock (1972) also observed that they spend a lot of time scanning foliage and twigs.

 

Nuttall's Woodpeckers eat insects (e.g., beetles, ants, bugs, caterpillars, etc.), and they also eat "vegetable matter" (e.g., seeds, berries, and flower buds).

Now this gets tricky.  Was this woodpecker eating oak flowers, or insects attracted to the oak flowers and leaves...or both?

Only the woodpecker knows...

 

P.S.  I'm not sure how to identify all of the local oaks yet.  My guess is that this is a Valley Oak (Quercus lobata), but please let me know if that's wrong.

P.P.S.  Facts above from the Birds of North America account by Lowther (2000), and Miller, A.H. and C.E. Bock.  1972.  Natural history of the Nuttall Woodpecker at the Hastings Reservation.  Condor 74: 284-294. 

 

Barking up the right tree?

 

Can you see the material in this titmouse's bill?

On 7 March 2015, we noticed this Oak Titmouse (Baeolophus inornatus) gathering nest material.  We weren't sure what the material was at first, but eventually figured out that she had a bill full of thin strips of bark.

I checked the Birds of North America account and learned a few things about nesting titmice (in Central California):

- They begin inspecting territories from late February-March

- They build nests primarily between mid-March and April

- The female builds the nest, and takes ~4-10 days to complete it

The base of the nest can be made of a variety of materials.  I was curious about how often bark was used.  (I felt the bark on this shrub and was surprised at just how soft it was.)

Of a survey of 188 nests, here's a basic rundown of what percentage of nests contained these different materials:

- grass (65%)

- hair (35%)

- moss (27%)

- feathers (26%)

- shredded bark (13%)

- sheep wool (11%)

- straw (6%)

- twigs (4%)

- plant down/fibers (2%)

- rope/string (2%)

- oak blossoms (1%)

- snakeskin (1%)

- sycamore seed balls (0.5%)

- rootlets (0.5%)

- leaves (0.5%)

- wood chips (0.5%)

The summary didn't say where the nests were from, and if the materials varied by site.  Are some materials more common in certain areas, or do these percentages stay the same wherever titmice are found nesting?

Have you seen titmice gathering nest material near you?

P.S.  Facts above from the Birds of North America account by Carla Cicero (2000).

White splash

I was finishing up work on Bodega Head at the end of the day and a white splash offshore caught my eye.  I took my binoculars out of my backpack, and then when I saw what had caused the splash, I dropped my field notebook and scrambled to get my camera.  

Sadly, the animals were too far away for photographs, but it was still very exciting to see a small group of Orcas — my first from shore in California!

It was hard to tell, but there were between 4-6 smaller animals (females or juveniles)...all actively swimming north towards Goat Rock and the Russian River area.

Then I glanced south and saw one very large dorsal fin — a male — separate from the rest of the group.

It was probably my imagination, but other animals seemed to be hugging the shoreline.

A group of California Sea Lions:

 

Two passing Gray Whales:

 

This is *not* an Orca from tonight, but instead one from Monterey, photographed from a boat.  I can't remember the exact year (it's from a scanned 35 mm slide), but it's probably from the early 2000s:

 

Although Orcas are rarely seen from shore in this area, keep your eyes open!  Conditions like today — flat, calm, gray seas — offer great viewing conditions.

 

Dashing around

There were quite a few Blue Dicks or Wild Hyacinths (Dichelostemma sp.) in bloom along the North Sonoma Mountain Trail on 7 March, and I started to wonder what might pollinate them.

 

Eventually I spotted a few insects visiting the flowers...and one of them was a nice surprise for me:

 

Although it might look like a moth at first because of its overall brown coloration, note the knobs (or swellings) at the tips of the antennae, indicative of a butterfly.

This is a fast-moving species, and I didn't get great pictures.  But here's a slightly different angle:

 

This is a Propertius Duskywing (Erynnis propertius).  [Propertius was a Latin poet, but I can't find an explanation for why this butterfly was named after him.]  Its caterpillars feed on oaks, many of which surrounded this grassland, so this was good habitat for this species.

I haven't spent much time around oaks since moving to California, so this is my first duskywing sighting.  It brought back memories of scrub oak habitat on Cape Cod...and the same feelings of frustration watching duskywings dashing around, hardly ever stopping, making it difficult to see their field marks and to photograph them.  As soon as I saw the way it flew, I knew it was a duskywing, and that it was going to be challenging.

Duskywings are territorial and this one was true to form.  It chased other butterflies that tried to nectar on nearby flowers.  Here's a shot of the duskywing after it dove at a lady (the butterfly at the lower right):

 

It will be fun to go back and try for better views.