Archive for December, 2009

Things That Go “Whoosh” at the Beach

Friday, December 25th, 2009

Julia’s involved with the snowy plover recovery effort at Coil Oil Point, which makes me really proud (and jealous). On December 13 she was the docent on duty when someone told her that a jogger had made a channel between Devereux Slough (which was very full at the time) and the ocean. The slough had been close to breaking through, and the docents were on the lookout for that to happen naturally as a result of rain or high tide, but for a human to engineer it was officially frowned upon.

Here’s what the slough looked like before:


Here’s what it looked like when she got to the place where the jogger had made the channel:


Once that channel was made it didn’t take long for things to get exciting. Julia headed back to the docent office, made a call to her boss, and a few minutes later was back at the channel. Here’s a short video she made when she got back, before her camera’s battery ran out:

A few minutes after that, Harold Marcuse made the following video from the other side of the channel. You can see Julia on the far bank:

Harold has some more photos in his blog posting I found at Edhat: Devereux Slough Breached. According to Julia, it was a pretty exciting event. The “whoosh” of the water exiting the slough was really loud.

On the subject of things that go “whoosh” at the beach, Julia also took some video of an event down at Padaro Beach, just west of Carp, yesterday (Christmas Eve). My sister M’Liz, my brother-in-law Steve, and my nephew Jamie were up for a visit, and they gave William an early Christmas gift of a model rocket, and helped us set it off.

The first launch didn’t go so well; we were using an older motor that didn’t have enough oomph to get the rocket off the launchpad (though it did have enough oomph to start a small fire and melt the pad, which was fun):

We did a quick repair with duct tape (hooray for duct tape!) and used a newer motor on the next try:

I was surprised by how much altitude we got. We were using a C5-6 black powder motor, which didn’t mean anything to me beforehand, but which I now know was rated to generate 5 Newtons of thrust, and to fire its streamer-deploying charge 6 seconds after burnout. The rocket arched slightly in the direction of the ocean as it ascended, such that Jamie commented, “that’s going in the water” (which you can hear on the video). We lost sight of the rocket at apogee, and apparently the streamer never deployed. If the streamer had deployed, I think there’s a good chance the rocket would have drifted back onto the beach with the gentle sea breeze, but without the streamer the rocket landed in the ocean, because that’s where we eventually noticed it, floating just outside the surfline.

After a few minutes of staring at it and trying (unsuccessfully) to flag down a passing paddleboarder, William demonstrated why he’s such an awesome kid by stripping off his shirt and swimming out to recover it. I don’t think this particular rocket is ever going to fly again, but at least now we have it for forensic analysis:


Bolas spider (Mastophora cornigera)

Saturday, December 12th, 2009

Last Saturday I was able to bird the “middle” portion of the Carpinteria salt marsh (normally inaccessible to outside visitors). Even better, I got to go in with Peter Gaede and Andrea Adams-Morden, two of my favorite people when I want to learn more about birds or plants (respectively). That’s damning with faint praise, though, in that Peter and Andrea are just fun to be with. They’re interested in everything going on in the natural world, always noticing things and always happy to share what they’ve noticed.

We entered on Estero Way, and worked our way out to the mouth of the marsh. Then we retraced our steps, and wrapped around next to the railroad tracks until we could walk out along the dike on the west side of the Santa Monica Creek channel. Toward the southern end of the dike there is a large patch of an invasive non-native with tall spindly stalks; Andrea tentatively ID’d it as black mustard (Brassica nigra). Here’s a shot looking past one of those stalks back toward the northwest:


I took that photo because Andrea had notice something interesting in the plant. Here’s a closer view:


It’s a collection of six spherical objects suspended in a loose web; Andrea’s guess was that they were spider egg sacs. Here’s a close-up:


There was one more interesting thing we noticed: Where the stem holding the spheres met the main stalk of the plant, there was a triangular structure that appeared to be made from the same silk as the web. You can see it on the left side of this picture:


Here’s a close-up:


We couldn’t find any spider to go with the putative egg cases, but after I got home I posted photos on, and within 15 minutes Charley Eiseman, co-author of the upcoming book Tracks & Sign of Insects & Other Invertebrates (which I can’t wait to buy) had ID’d the spheres for me. They are indeed the egg cases of a spider, specifically the Bolas spider Mastophora cornigera.

The spider is nocturnal; it hides in plain site during the day by looking exactly like a rounded bird dropping. (When I mentioned that to Andrea, she replied that she actually had noticed what she thought was a bird dropping on the plant not far from the egg sacs. I didn’t notice it at the time, and I can’t find it in any of my photos, unfortunately.)

The spider also has an interesting way of hunting: It dangles a strand of silk with a sticky ball on the end, and swings it with one of its legs to capture flying insects. The ball gives off a scent that mimics moth pheromones, and researchers have found that the spider can vary the scent over the course of an evening to appeal to different moth species that are active at different times of night.

Here’s a segment from David Attenborough’s Life in the Undergrowth showing M. cornigera hunting:

One mystery I still haven’t solved: What was that triangular silk structure at the base of the stem? I tried sending an email to Peter Bryant, a biologist at UC Irvine who has posted some neat photos of Bolas spiders on the web. I wrote him as follows:

I came across what I believe are some Mastophora cornigera egg cases yesterday at the Carpinteria Salt Marsh. I’m curious about one thing, though: There was an odd triangular structure, apparently built out of spider silk, at the point where the stem from which the egg sacs are suspended meets the main stalk of the plant. You can view a photo of the structure in relation to the egg sacs here:

…and a closeup of the triangular structure here:

At first I was thinking the structure might be a hiding place for the spider, but now that I’ve had some help identifying the species, and have looked at the wonderful photos you’ve posted of the adult female, I don’t think that structure would be large enough to hide one (and it doesn’t sound like they go in for that sort of thing, anyway, given their impressive bird-dropping mimicry).

I’m trying to figure out what purpose that structure might have. My lay speculation so far consists of:

* The aforementioned hiding place for the adult spider.
* A structural reinforcement, to prevent the weight of the egg sacs from causing the stem to break off the plant.
* A barrier to help prevent egg-sac predators from traveling from the stalk to the stem.

I’m curious if you know the answer, or would be willing to speculate. Thanks!

Dr. Bryant wrote me back, but unfortunately he didn’t have any ideas about that triangular silk structure. He suggested visiting the location again to see if the spider is nearby, which I’d love to do, but so far I haven’t had a chance (and I’d need to go with Peter, or someone else with official permission to enter that part of the marsh).

More Bolas spider links:

Upper Santa Monica Creek!

Tuesday, December 8th, 2009

I haven’t done a Christmas bird count in more than 30 years. But on December 19, 2009, I’ll be fixing that. Carp is going to have its own count this year, thanks to the efforts of Rob Denholtz, one of my fellow salt marsh docents, and I can’t wait.

I set up some Google maps of the count circle, and have been scouting likely locations. Last Saturday I had a really thrilling day of birdwatching. I started before dawn at Carpinteria Creek, then went into the normally-inaccessible part of the salt marsh with Peter Gaede and Andrea Adams-Morden (more about that in a future post), and then got to do something really special.

I’ve talked before about Santa Monica Creek. The lower, channelized part of the creek runs through my neighborhood, but upper Santa Monica Creek, which is not channelized, is a little harder to visit. It runs though Rancho Monte Alegre, which used to be a working ranch, but now is owned by RMA Partners, a development firm that is building a number of high-end houses there. A few years ago RMA Partners got together with The Land Trust of Santa Barbara County and The Trust for Public Land, and placed more than 3,000 acres along upper Santa Monica Creek into a permanent conservation easement controlled by The Land Trust.

Eventually there is supposed to be public access to the area via a series of trails, but for now one can only visit it by special arrangement. With the upcoming Christmas count as my incentive, I got in touch with Tad Buchanan at RMA Partners, and he agreed to let us enter the parcel for a scouting trip, and again on the count day. Last Saturday we did the scouting trip.

It’s beautiful. Here’s the view we had as we started hiking up the dirt road that parallels the creek:


One of the neat things about the trip was that Peter Gaede came along. Peter is one of the best birdwatchers I’ve ever met; I always learn a lot when I get to go birding with him. Do you think he’s excited about getting a chance to check out habitat that hasn’t been actively birded in years, maybe decades?


Here are all my companions from the scouting trip. From left to right, that’s Peter Gaede, Andrea Adams-Morden, Geoff Stearns, and Rob Denholtz. They’re enjoying the view of the salt marsh, which was at a max high tide of about +6.3 at the time.


We saw lots of birds (naturally) but the most exciting thing we saw (for me at least) were all the fresh tracks on the road. Along this one stretch of road there were tracks of coyote, roadrunner, weasel, bobcat, and bear — two of them, a mother and her cub, I assume. That’s mama bear’s track on the left, and baby bear’s on the right:


This old cabin was just a few yards from the creek:


Finally, here’s some really nice riparian habitat where I know we’re going to get some great birds on the count day: