Saturday, June 16, 2012

A royal surprise

It's been hot and dry here so mushrooms were the last thing I expected to find in the woods at Howarth Park! Agaricus augustus is also known as The Prince. They are considered to be quite tasty but a seething mass of larvae got there first.




Read more about The Prince:
Tom Volk's Fungus of the Month, August 2002
California Fungi
Morel mushroom hunting
Wikipedia

Monday, June 4, 2012

Why do Western skinks have bright blue tails?

Youthful blue tail fades then turns dirty orange.

In my last post I mentioned seeing Western skinks (Plestiodon sketonianus) hanging out with Western fence lizards. I always thought skinks were shiny because they're moist, like salamanders, but, really, it's that their scales are so smooth and rounded that they reflect light like a piece of glass. When they're young their tails are a bright, screaming blue. As they age the blue fades and eventually their tails are a dull orange brown. When I first began to watch them I thought that blue tail, though really pretty, seemed like a terrible idea. It's awfully easy to find the youngsters as they hunt just by watching for that flash of blue. It's like a bright neon sign pointing the way to an otherwise secretive creature.

A breeding male with paler tail and orange on chin and face

When I asked Google why skinks have blue tails I found many websites promoting slightly different versions of the same story, which is that Western skinks have blue tails so that predators are attracted to the tail rather than the skink's body. Then, when the predator grabs the tail, the skink separates itself from the tail and runs off to be free, if quite a bit shorter. Each time I read the story I became more skeptical about it. For instance, why would only the young skink need that kind of protection? For that matter, why would any creature want to attract a predator to any part of it's body? Why not be like so many drably colored creatures that blend beautifully into their surroundings? I decided that this explanation of the blue skink tail was a very poor one and kept following links, hoping to find something more plausible.

Western skink lying in wait for breakfast

Several pages into my Google search I came across an article written in 1970 for a publication called Herpetologica. The authors shared my skepticism about what they called the decoy theory. Although their article was about a different species of skink, they proposed that the blue tail was a way of letting mature males know not to get territorial and aggressive toward the youngsters they crossed paths with during breeding time. The authors conducted a not entirely conclusive study to support their theory. Their explanation and theory seem a bit more convincing but I think that, for now, blue tail might just be one of those lovely mysteries that must remain unsolved. For now, anyway.

Another day, another young skink hunting.
References:

•Kaweah Oaks
•Function of the Blue Tail-Coloration of the Five-Lined Skink (Eumeces fasciatus)Author(s): Donald R. Clark, Jr. and Russell J. HallReviewed work(s):Source: Herpetologica, Vol. 26, No. 2 (Jun., 1970), pp. 271-274. Published by: Herpetologists' LeagueStable

Thursday, May 24, 2012

A gathering of lizards

Where the lizards gather
 I've read that Western fence lizards (Sceloporus occidentalis) tend to be loners, defending their territory fiercely. There's a rocky place at Howarth Park where I like to sit and watch lizards, birds, insects and the occasional California ground squirrel go about their business. In winter the lizards are tucked away under rocks and in the ground but when the sun warms up those rock, the lizards come out of hibernation.

Fence lizards and a skink hanging out
One morning in early spring I arrived just as the sun hit the rocks and was pleasantly surprised to find a gathering of several lizards andl Western skinks (Plestiodon skiltonianus) hanging (literally) together on the vertical face of the rock. As I watched a few more emerged from holes in the wall and within an hour most had dispersed and could be found hunting within view.

Western fence lizards easing out of a tiny cave in a big wall of rock
Entranced, I returned several mornings in a row. The first couple of days the gathering was large. The weather became unseasonable warm and by the time I arrived (between 7:30 and 8 a.m.) the lizards were already out hunting. The skinks appear to come out later than the lizards and I was usually able to see them straggle out, sun for a bit and then glide off for some breakfast. After a few days, the gathering was much smaller but when I looked closely I could see lizards and a few skinks scattered among the rocks, hunting and defending territory.

Tuesday, May 15, 2012

Another slug

Reticulate tail dropper

A few weeks ago it had rained a bit and, as I sketched a Banana slug (Ariolimax columbianus) devouring the leaves of a Wild cucumber (Marah oreganus) plant, this little fellow ambled across the rock I was sitting on and buried itself in debris that had built up in a crevice in the rock. It was gone before I had a chance to sketch it but I lucked out the next day when I saw a white mushroom glowing in a patch of Poison oak (Toxicodendron diversilobum) and went closer to inspect it. Not only did I find fungi but I found two of these little slugs having a feast. I was able to pick up the mushroom and take it out of the Poison oak and sketch one of the slugs while it ate, then return the mushroom to it's original location with the slugs still attached.

Though slugs don't actually have tails this native species is called Reticulate tail dropper (Prophysaon andersoni) because they're able to self-amputate the back end of their bodies much in the same way that lizards release their tails when captured.

 Learn more about Tail droppers:
Identification Guide to Land snails and Slugs of Western Washington
Wikipedia
Living Landscapes

Sunday, May 13, 2012

Slug and Manroot

Banana slug stealthily eating manroot leaves
A few weeks ago we were having unseasonably cold weather and I found myself looking, though unsuccessfully, for Banana slugs (Ariolimax columbianus) as I walked in the cold, gray early mornings. Then it got a bit warmer and rain gave way to blue skies and sun. I gave up on the slugs and went off to look at a Manroot or Wild cucumber plant (Marah oreganus) that I'd been admiring in a somewhat secluded rocky area.

Headed home for the day
I noticed an odd color in the depth of the plant and lo and behold! I'd finally found a banana slug! Wild cucumber produces upright stalks of small white flowers and the deer scat near the slug told me who had eaten nearly every flower off of the plant. As the sun rose higher in the sky the slug began it's journey home. I was thrilled because I've often wondered where these creatures go when the sun is out.
The slug moved slowly, producing enough slime, as it traveled, to help carry it safely over dried leaves, twigs and rocks. I had plenty of time to admire it's moves, contemplate the meaning of life and rearrange my bag. I was even able to plot it's course and identify it's home before it actually arrived at the small cave in the rocks and disappeared slowly into the dark.

A young banana slug
The weather remained cold for several days and I returned a few more times. In all, I found three different banana slugs eating the Manroot leaves at different times. One was quite small (3.5 inches long) and must have been a youngster. The other two were adults and easy to tell apart because one had almost no spots and the other had many.

It'll be a while before I see any of the Banana slugs again. During the dry summers here in Santa Rosa these native creatures estivate (the summer version of hibernate).

Think you know all there is to know about slugs? Think again:
 Slugs: A Guide to the Invasive and Native Fauna of California by Rory McDonnell
 CreationWiki
San Francisco State University Department of Geography
treehugger.com
National Parks Traveler
Birds Amoré

Monday, May 7, 2012

Dressing up to do battle

One afternoon, at the end of March, I went looking for one of my favorite spring wildflowers, Marah oreganus, also known as Manroot and Wild cucumber. It sprawls along rocky places and I had recently discovered that it grows wantonly  in a partially quarried rocky area in Howarth Park. As usual, I had trouble figuring out how to draw this long, sprawling plant and was thinking about giving up when I heard a tiny ruckus on the next rock over. I looked up to see two Western fence lizards (Sceloporus occidentalis), in colors I'd never seen before, fighting and posturing with great vigor. I thought there might be a female involved and I soon found her, peering out of a crevasse on a ledge below the action. The males continued to interact with one another for quite a while. Then one of them left, only to return again, and they picked up where they'd left off. A bit later they both went to opposite ends of the slab and rested up for the next round. The female had climbed out of the crevasse and looked a bit exhausted, though she began to recover (from what?) before very long. As the males resumed their battle, a young lizard climbed up the to view the proceedings from the edge of the rock. One of the males chased him away and I watched as he headed my way, only to stop short when he noticed me noticing him. When I once again turned my attention to the territory struggle, the female had climbed up the cliff and was standing next to one of the males. The other male turned around and headed off slowly through the grasses at the edge of the battleground. I watched him until he disappeared and when I looked back at the victor and his mate, I was astonished to find that his brilliant colors and pattern had reverted to a pattern almost identical to her drab brown!