Thursday, May 13, 2010

habitat ~ 05/13/10 ~ Elkhorn Slough - NERR

Elkhorn Slough - NERR entrance
May 13, 2010

Simply uploading pics that provide a sense of where I was on this day and what the weather was like. I brushed off at least two dozen ticks while on Hummingbird Island. Oy vey! Well... okay, my usual slick, hiking pants were in the laundry, so I wore my clingy, black workout pants. Bad idea! I think it's going to be a boomer tick year. I tried to take pictures of several small snakes, but they slithered into the tall grass before I could get my camera out. We also saw more rabbits along the paths than we could count. Why do I always think of Watership Down when I see so many rabbits? A couple volunteers cornered us and insisted we not go anywhere near the barn due to an owl being down. Huh? They have a couple owl nests in there, but I didn't catch what was wrong with the owl.

cliff swallow ~ 05/13/10 ~ Elkhorn Slough

cliff swallow
Hirundo pyrrhonota

I was amused to see the mass numbers and enclosed shape of the cliff swallow nests compared to the single, open barn swallow nest I found in Oregon last year. These cliff swallows look stern to me; maybe it's the white brow.

Growing up in the Central Valley, we had "mud" swallows attempt to build numerous nests on our house. Every weekend my dad would wash off the mud from the eaves with a hose. I'm guessing they were cliff swallows now that I know cliff and barn swallows are the only ones to build mud nests in California and the differences between the two.

It seems to me Elkhorn Slough folks used to try to keep the swallows away from the nature center and research buildings with reflective strips of ribbon. Now, there's a "Shhh!" sign to caution visitors from disturbing the nests. I can imagine by the end of the nesting period, that artistic splatter of droppings could well end up being a significant pile of poop.

I usually don't link to IPM sites, but both links in the common and scientific names above are for management. In a previous entry I gave the Cornell-supplied genus of Petrochelidon. I'm not sure which name is now most commonly used.

milk thistle
Silybum marianum

Just looking at photos, you'd think this plant is attractive. However, I could really do without milk thistle on hikes. The leaves are extremely prickly and hurt through thin hiking pants. I wasn't surprised to find out it's an invasive plant.

ps 04/14/11 - Found this blog post from FeralKevin about preparing thistles as food. See comments below for how I got to this.
granary tree of an acorn woodpecker
granary tree of a Melanerpes formicivorus

ps 12/05/10 - After considering Blue Jay Barrens recent post of woodpecker holes, I'm back-posting this with a quick embedded link above. The tightly packed holes shown above are very different looking than what Steve featured on his blog. I usually see several granary trees grouped together.

ps - 03/04/11 - I edited the above and removed the embedded links, because Steve removed his blog from public access. Interesting idea... Say, do you notice one trunk is totally hole-ridden and the one next to it looks basically intact?
American white pelican
Pelecanus erythrorhynchos

This is about as close as I've been able to get to white pelicans. The last time I saw them was in Morro Bay last June. Can you believe they have a 9-foot wingspan? I knew they were big, just not that big. Unlike solitary brown pelicans that do incredible dives into the water, the white pelicans fish in groups, as seen above. There are several other types of birds in the picture, but they were too far away to get any detail.

CA hedgenettle ~ 05/13/10 ~ Elkhorn Slough

orange-rumped bumble bee on California hedgenettle
Bombus melanopygus on Stachys bullata

So, where's the orange rump? According to an old post from Seattle, WA, only females have the orange band??? I thought this bumble bee would be easy to identify to species. Nope. After pulling my hair out the other morning over paintbrushes and owl's clovers IDs, I was ready to simply call this a Bombus sp. and call it a day. This is definitely not one of the two most commonly mentioned CA species, the yellow-faced bumble bee (B. vosnesenskii) nor the Sonoran bumble bee (B. sonorus). Thanks to a lovely photo ID site from UC Irvine (also linked in common names here), I'm fairly confident of this ID even though I read somewhere there are 27 described species of bumble bees in CA (and probably several more undescribed).

As evidence of why I prefer photos of the living, versus collection specimens, check out this Discover Life site of pinned B. melanopygus. I dare any lay person to look at those pinned bees and think, oh yeah, that's what I saw. With the explosion of macro photography and institutions wanting to share their resources online, I predict we'll be seeing better and better ID sites in the near future. Often one photograph is not enough; it's preferable to have a whole collection of photographs. Sometimes this can be a burden, especially when those photo collections are not always reviewed for accurate identification. However, I'm still glad to see this trend.

I'm fairly confident of the plant ID, too. The other possibility is rigid hedgenettle (Stachys ajugoides ssp. ajugoides), but it just didn't have the right face to me.

There's also another insect next to the bumble bee. I can't tell from my pictures if it's a plant bug or a beetle. My pictures are still much improved from last year.
Asian horn snail / Japanese false cerith
Batillaria attramentaria

Eww! What are those things? Listen here, I'm generally not a squeamish person, save for slimy, crawly maggots... unless I'm raising flies to feed mantids, but that's a story for another time. For some reason these mud snails really gross me out. They're similar to our native horn snails (Cerithidea californica), but hail from Japan. Simply based on the massive numbers shown above, I'm guessing these are the invasive species. Click on the common names above for more information on local research.

leopard shark and anchovy ~ 05/13/10 ~ Elkhorn Slough

While hiking at Elkhorn Slough with a friend this afternoon, we came across this unusual sight of people in the water with a huge net. What are they doing?!? So, we stuck around to watch.

Oooh, there's something moving in that net! There are two somethings! Leopard sharks! The sharks were not happy campers at being caught, but they didn't flail about as much as I thought they would. They looked incredibly strong, though.

After checking the sex and recording some basic data, these folks then proceeded to collect all those little silvery fish in the net and count them. I overheard that some were anchovies and identified mainly by their large jaws.

leopard shark
Triakis semifasciata

Within 10 minutes the researcher fellow let the sharks loose back in the water. I would have jumped in to ask questions, but these folks appeared to be extra busy collecting those little silvery fish. Link forward to learn more about monitoring sharks at Elkhorn Slough. Cool!