Shallow Thoughts : tags : newts

Akkana's Musings on Open Source Computing, Science, and Nature.

Sun, 10 Jul 2011

Newt larvae at Sanborn

It's always fun to look for newts when we go on walks in the woods. We're always reading that amphibians are in mortal danger -- they're more susceptible to environmental toxins than other vertebrates, and they're dying off at frighteningly high rates. So seeing newts, salamanders or frogs always makes me happy ... and seeing a new generation of them makes me even happier.

[ Newt tadpole ] [ Newt tadpole ]

Therefore, in spring and early summer, I always check the ponds for tadpoles and newt larvae. Usually I don't find any. But this year I got lucky: the little decorative pond at Sanborn county park had newt tadpoles when we checked last month (June 18), and yesterday we saw one in that pond and two in the lower pond.

[ Adult and larval newt ] Photographing tadpoles is tougher than photographing adult newts. Of course, they're always under water, so there are reflections and refraction to deal with; and it's usually mossy stagnant water, so you have to wait for them to come out from under the moss. They're also shy, and dart away if they see motion above them -- not surprising for something so small and defenseless. (Adult newts are pretty casual and it's easy to get fairly close to them ... maybe because they're poisonous.) [ Detail of larval newt from previous photo ]

So, okay, not exactly National Geographic material. But I was excited to get any photos at all that show both legs and gills, as well as one showing an adult newt with a larva right next to it. Coincidence, of course: newts don't care for their young. But it's fun to see the difference in size and shape between adult and youngster, and equally fun to see how much the larvae changed in three weeks' time from the first shots to the second.

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[ 12:42 Jul 10, 2011    More nature | permalink to this entry | comments ]

Wed, 20 Jan 2010

Newt nookie!

[Newt nookie at Lake Ranch] Last weekend, on a tip posted on a local birding list, we hiked up to the little pond at Lake Ranch, above Sanborn county park, where a major California newt orgy is in progress.

There were thousands of newts throughout the lake, but especially by the dam, where they were mating and laying eggs.

I had never realized how much the male newts' appearance differs from the females -- or possibly, it doesn't except at this time of year. Most of the year, when we see newts they look like these females, with orange-red skin and lizard-like feet. But here the males look very different: larger, darker, often patterned with stripes or spots, with huge flipper-like feet and greatly flattened tails.

Most of the females were gravid with eggs already. The males seem to be able to tell when a female has already been fertilized, but only from up close: they'll pursue a female to a few inches away, then turn back if she's recently mated.

We saw some multi-newt orgies, with two or three males nosing each other to get access to a female; but mostly we saw pairs clasped in long-lasting embraces. We watched a few pairs for five or ten minutes.
[California newt laying her egg sac]

Some of the females laid their grape-sized egg sacs near where they mated, by the dam; but upstream, closer to the Black Rd end of the pond, we found a nursery where the pond floor was just covered with egg sacs. Is it safer for the eggs here, away from the newt festivities? Or is the temperature or oxygen content different?

Photos are a bit challenging. There's a lot of reflection off the surface of the water. The raw photos are just a sea of murky green, but a little contrast boosting in GIMP, and sometimes a bit of layer mode/layer mask work, brings out a lot more detail than I expected.

There were a few frogs singing, too. We couldn't see the frogs, but we did see a few schools of what might have been tadpoles (or else tiny fish). We also saw one huge tadpole, with a head like a squashed ping-pong ball. I hope the bullfrogs from Walden West pond haven't migrated up to Lake Ranch. It's fun to watch them at Walden West, but bullfrogs could wreak havoc on the pond's other wildlife. (Can bullfrogs eat newts? Most animals can't -- newts have poisonous skins. But we've never seen any newts at Walden West.)

If you go to see the newts, watch your step on the trails. After egg-laying, the females apparently leave the pond and go wandering cross-country. (Where do the males go?) We saw at least three females heading down the steep trail toward Sanborn, and a couple more on the flat trail above the lake that heads toward Black Rd. They move slowly and purposefully, and can't scurry out of your way to keep from getting stepped on. So be careful, and enjoy the show!

Newt nookie photos here.

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[ 11:06 Jan 20, 2010    More nature | permalink to this entry | comments ]

Thu, 21 Aug 2008

Pond denizens struggle against mud

On a short afternoon hike at Sanborn today, Dave and I decided to go by the tiny koi pond near the visitors' center to see if any newts were left this late into summer. [newt stuck in mud]

What a scene! In the current semi-drought, the pond has become a mud flat, its surface criss-crossed with tracks and squirming with newts and crayfish trying to push themselves out of the sticky mud.

In the few holes where the water was more than a couple inches deep, fish flopped -- several 6-8" long golden koi plus something brown but similarly large. A few of the newts thrashed in the water holes, too, seemingly trying to get clean of the mud that coated them; but most of the newts wriggled across the shallower mud flats, heading nowhere in particular but looking very unhappy. The crayfish seemed most numerous at the dryer edges of the pond, pushing themselves laboriously up out of the mud with their claws and dragging themselves across the mud.

Newts normally migrate, and can go surprisingly long distances (miles) across land, so I think at least some of these newts will survive. The fish, I must assume, are doomed unless someone rescues them. I wonder if the rangers have considered selling the non-native koi to someone who wants them, and replacing them with native fish? Are there any fish native here this far upstream? Penitencia Creek (at Alum Rock) has small fish (up to about 3" long), but it carries more water in dry seasons than any creek near Sanborn.

What about the crayfish? Can crayfish survive long out of water, bury themselves in mud (the ones here didn't seem too happy about that idea) or migrate overland?

I suspect there will be some happy park raccoons tonight.

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[ 20:21 Aug 21, 2008    More nature | permalink to this entry | comments ]