Monday, July 24, 2017

18-July-2017 North Mountain, Washington

Site location map. Click to enlarge.
Since habitats on the east side of the Cascades are now too dry to be productive, Rod Crawford and I decided to head north to North Mountain, a mid-elevation site near Darrington in Snohomish County. We collected in the area in May of 2016, but at lower elevations. I was excited to reach to fire lookout atop North Mountain and take in the views of Whitehorse Mountain, Mount Baker and perhaps even get a glimpse of Glacier Peak. Oh, and collect spiders there, too...

Rod on final approach to the
fire lookout.
Mt Baker as seen from the lookout. The
view was hazy due to moist marine air.
After some confusion as to which road was the one leading to the lookout, we arrived at the locked gate and continued the final 1.5 miles on foot. It was a hot and somewhat humid hike, but a refreshing breeze was blowing through the lookout, which was under renovation and therefore had no windows. The views were just as stunning as I'd hoped.

But to work! After feasting my eyes on the scenery, I came back down to earth and set about tapping Douglas-fir (Pseudotsuga menziesii) cones near the base of the lookout. Except for a few harvestmen, however, those cones were arachnid-free.

Female Orodrassus canadensis
guarding her egg sac.
Female Pardosa mackenziana with
egg sac
The renovation work on the lookout meant that there were pieces of wood scattered about, so I next began looking beneath them for spiders. I didn't find many, but what I found certainly made the effort worthwhile. One wooden post on a concrete slab was sheltering a male Cybaeus reticulatus (Cybaeidae) and a female Orodrassus canadensis (Gnaphosidae). When I rolled the post aside, the top of the Orodrassus' nest-refugium got pulled off. This left her and her egg sac visible for a nice photo. I also found a few female Pardosa mackenziana (Lycosidae) under stones in a roadside outcrop a few hundred feet below the lookout.

Male Misumena vatia stepping onto
draglines that led to...
...a female Misumena vatia eating
a fly.
Big swaths of goatsbeard (Aruncus dioicus) were in full and glorious bloom along the roadside, so while Rod searched for conifer litter to sift, I began examining goatsbeard inflorescences. Not surprisingly, everyone's favorite crab spider Misumena vatia (Thomisidae) was numerous therein and conspicuous. I spent quite some time observing a male traveling on draglines between two adjacent inflorescences. Each inflorescence had an actively-feeding penultimate female near its apex.

Clubiona pacifica nest in goatsbeard
Opening the Clubiona pacifica nest
made in goatsbeard leaflet
As fun as it always is to watch Misumena vatia, the really exciting, novel observation of the day came as Rod and I began our walk back down to the car. As Rod was diligently sweeping roadside herbs, I was quite honestly just enjoying a leisurely downhill ramble while photographing the occasional bee or spider in the nearly endless stream of roadside goatsbeard. That's when I noticed that something had folded the end of a goatsbeard leaflet into a neat, triangular package.

Opened Clubiona pacifica
nest after removal of female.
Clubiona pacifica nest in alder leaf
Upon opening it, we discovered a female Clubiona pacifica (Clubionidae) and her egg sac inside! Water droplets on the inside of the silk-lined package indicated that this was perhaps a moisture-retention mechanism as well as a predator control device.

Clubiona pacifica juvenile in silken tube
Shortly thereafter I spotted another triangular C. pacifica nest, this time made from an alder (Alnus) leaf. I also found a third, albeit juvenile Clubiona in a tubular silken structure in a goatsbeard leaflet that had been folded in half lengthwise.

Lower Doug-fir cone site
Productive Doug-fir cones
Heading back down the mountain, we stopped in a stretch of mature Douglas-fir and red-cedar (Thuja plicata) forest where Rod spotted some old stumps and downed wood he wanted to tap. I decided to take another crack at tapping Doug-fir cones, and this time had some luck. I tapped 100 cones and collected 16 spiders from 3 families. At 7 individuals, Cryphoeca exlineae (Agelenidae) dominated the sample and was the only identifiable species present.

Read Rod's account here.

A female clodius parnassian (Parnassius clodius) near the
North Mountain lookout

View of Whitehorse Mountain as seen from a clearcut on North Mountain.
Fireweed (Chamaenerion angustifolium) in foreground.

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