A Trip to the confluence of the NF Toutle and Green Rivers

Roving Temple of Ultraviolet Light at the ridge above the confluence of the NF Toutle and Green rivers

Written on August 29, 2023, more or less in real time: Since the first time I visited this area on the ridge above the Sediment Dam on the NF Toutle a couple years ago with my nbo Morgan, I’ve wanted to come up here and run lights. Not only is it a very nice second growth forest with a good mix of relatively mature conifers and deciduous trees, sitting on a ridge above the confluence of two of the main watersheds for the northwest side of Mt. St. Helens, it also has an old abandoned road that was cut straight through the forest, so that there 3 places with long sightlines, and my lights would be visible to anything crossing that opening for a good hundred yards in each direction. 

Open sightlines through the forest

This past summer on a nature walk through here I discovered, or more accurately my grandson Lee discovered, another reason to wander around in the dark in this area- at least a dozen little holes in the ground that I believe to be the burrows of folding door (ETA- I am going back and replacing all of the places where I said ‘trapdoor’ spider with the correct term ‘folding door’ spider, since Rod Crawford informed me that the term ‘trapdoor spiders’ is only applicable to certain members of the superfamily Avicularoidea, which does not include Antrodiaetus, and ‘folding door spiders’ is the appropriate common name for the members of the family Antrodiaetidae) spiders (probably in the genus Antrodiaetus). Since then I’ve been trying to coordinate a trip up here with Lee, but things keep getting in the way. Today was finally going to be the day we’d make this expedition, but once again unforeseen circumstances thwarted my plans, and the only adventure Lee had time for was a couple of hours of fishing. When I dropped him off I figured to just head home myself, but the more I thought about it the more I realized that it was unlikely I’d get back up here before spring, and it was only a thirty mile detour, so I got off the freeway at Toledo and headed towards St. Helens. 

NF Toutle just above the Sediment Dam

Conditions tonight are far from ideal, but I still have high hopes. Temperature at sundown, here at about 800’ elevation, is 64⁰, and there is enough wind that I staked down the Temple of Ultraviolet Light I had erected. However I am under the tree canopy, and cloud cover is about 60%, both of which should help hold the heat, but the forecast is for 80% chance of showers, so I doubt that I’ll escape getting wet. This area was not impacted directly by the eruption of Mt. St. Helens, and the forest is healthy, so there should be some invertebrates that visit the Temple, and really, if I can find even a single folding door spider I will be ecstatic. I don’t know if these spiders are attracted to UV lights, and somehow I doubt it, but some arachnids, such as harvestmen and solipugids, seem to be, so maybe I’ll get lucky. For now I’m just going to stroll slowly along this old road, and see if I can spot one with my headlamp. 

Dusk at the Sediment Dam

8:32- Almost fully dark now, and I’m getting some winged termites at the light, as well as a Herpetogramma and possibly a Homotherodes moth. It may be a fool’s errand looking for folding door spiders, since the forest floor off the immediate trail is not as open as it seemed in daylight. 

I thought this photo of the post sunset river and surrounding forest ended up looking like an impressionist painting

9:16- Temperature is down to 62⁰, and the wind has dropped to almost nothing. It is very pleasant here, and very peaceful. And, I hesitate to admit this, a little boring. I’ve slowly walked the trail for a few hundred yards on either side of my setup, and the only animals I’ve seen were a few unidentified slugs and two Allogona townsendiana (Oregon Forest Snail). After an initial flush of action at my light the number of visitors has really dropped off. It is late August after all, and many, if not most, of the moths have finished the adult portion of their lives and gone off to the big UV light in the sky. I’m not ready to pack it up yet, but I do have an 80 mile drive home and I’m not inclined to put that off until the wee hours if all I’m doing is donating blood to nourish the eggs of the local nocturnal mosquito population. 

Misumena vatia

10:24- I was disappointed in myself for my boredom, so I headed off again into the night, but this time I scanned everything, instead of just the ground. And I was soon rewarded with a male Araneus diadematus (Cross Orbweaver), and then a female. And shortly after that I found a fairly large weevil on a salmonberry leaf, and then another and then a mating pair, all of which I believe to be Panscopus gemmatus. I also found a female Misumena vatia (Goldenrod Crab Spider) lurking on an elderberry leaf, and an intact but dead Phlogophora periculosa (Brown Angle Shades Moth) stuck with its head through a chewed out hole in a leaf. Nothing spectacular, and not nearly as many insects as I’d have expected given the amount of leaves I saw that had been chewed on, but it was fun and evaporated my boredom. But what really jacked me up was getting back to my lights and finding what I believe to be a folding door spider crawling on the floor of the sheet tent! I can’t see the in-line chelicerae that definitely would mark it as a mygalomorph spider, but it matches the search image I have for Antrodiaetus (thick dark legs, large, hairless, dark carapace with a sunken center, thinner abdomen with separated spinnerets)I had to counsel myself strongly to force myself to get some in situ photographs, and sure enough it bolted after the third one, but for a change I got the container in precisely the right place and he (I’m assuming it’s a he because of the large clubbed pedipalps and the fact that it’s the males that wander about looking for a mate) ran right into it. Fingers crossed!

Male Antrodiaetus, possibly pacificus

11:08- I wandered down the trail back towards the main road this time, finding a dead and leafless shrub that was full of webs and spiders, mostly Neriene litigiosa (Sierra Dome Spider)  and more cross orb weavers. Then beside that I found a single spider in a live salmonberry, and it’s either an odd morph Cross orb weaver, or (hopefully!) my first cat-faced spider. It would appear that we are now out of prime moth season and into the time of spiders, and hopefully I’ll be able to make some positive identifications in the next 6 weeks. It’s only down to 60⁰, and it’s still not raining, but the flow of moths has shut off completely, so I think I’ll start breaking down the setup. 

Weevils making more weevils

11:58- Packing up never goes as quickly as I think it will, but for a change I wasn’t slowed down by finding interesting and hidden moths in the little niches of my setup. What I did find were 2 Monadenia fidelis snails on the underside of the tent floor! I am amazed and grateful that I hadn’t crushed them crawling around to photograph moths, and really happy to finally see some again, since the couple I had found since starting this project came when I had no means to document them, and these beautiful snails deserve to be profiled. As I was working I was serenaded by a haunting single note call, 1-2 seconds long, that was possibly a barred owl, but my ear birding skills are almost non-existent. All in all a very pleasant and productive evening, and I should be home before the 1:30am deadline I gave my wife, meaning I don’t need to chance waking her with a text, and she won’t worry if she does awaken after that time. 

Former Phlogophora periculosa

7 thoughts on “A Trip to the confluence of the NF Toutle and Green Rivers”

  1. I love reading these, I just sit here cracking up… “gone to the big UV light in the sky”… you really brighten our days with your explorations and your talent for writing Dan! I love that area, I walk on that easy boardwalk trail across from Seaquest Park alot, so enjoyable with the lily pads and all the birds. The photo of the moth is great!

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