What conditions are best for searching for anthropods on snow?
I seem to have the best luck finding arthropods on snow on days when there is fresh snow on the ground and temperatures 20 to30F (-5 to 0C). A few snow flurries in the air are OK, but if there's heavy snow falling, the spiders and insects are nowhere to be seen. I also found more creatures in the deep woods than out in the open. How about you? In your experience, what weather conditions make a good day for arthropod hunting on snow?
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My three contributions so far here were on warmer days, up to 7C, with snow on the trail that was heavy and granular from the partial thaw. The thaw could've signaled them to come out, perhaps to breed or feed, but also the thaw meant I'd be more likely to be out enjoying the day, increasing my chances. So I'm unsure which factor, or if both were in play. It's too small a sample size across too many different organisms (3 different species) to draw broad conclusions from.
Chionea are best observed during heavy snowfall and immediately afterward, at temperature between 0 and -5 degrees.
This has been a really good winter for finding arthropods compared to other years. I have had luck with -1 C and warmer, those most sightings the temperature has been above zero. Sunny seems to be preferred but I have also found them on cloudy days. The majority of my observations have been in open areas vs wooded areas. I have observed Spiders literally climb over Snow Fleas and don't appear to consume any :) For some reason I find a lot in "boot prints" in the snow.
According to my observations, snowflies prefer darkness over daylight
Forests are said to be better, as the vegetation (tree trunks, etc.) create more passageways from the subnivean zone to the surface. I think fresh snow helps primarily because it makes them easier to spot. Clear days have been less productive for me than cloudy ones.
I chanced upon my arthropod (winter stonefly) on a day when the temp was in the mid-40's after several days of sub-freezing temperatures, and it was a bright sunny day. There was about a foot of snow on the ground, after two snowfalls several days apart. The first snowfall left a crust of ice upon which more snow fell, about a week prior to the observation, and there had been a small sprinkling overnight. I found it in an undisturbed wooded area near a wide creek which flows all the time, summer and winter.
Undisturbed woods, near a creek, after snow. All great conditions!
@erikamitchell Good point, I've only ever found winter stoneflies close to creeks and streams. And not just any stream will do, but only those with the proper substrate. Some of the more disturbed, muddy-bottomed creeks around Burlington don't seem to host winter stoneflies at all.
The creek I mentioned above has a rocky bottom - I guess "stoneflies" like rocks!
I found my recent arthropods (wolf spider, Trichocera, Isotoma) on an unusually warm day for here in New Brunswick (7 C in mid Feb!!!) and they were closest to my compost pile (which receives weekly donations from our rabbit litter boxes year-round), and also near my hay storage shed. Except for the Hypogastrura, which were just everywhere!
I'll have to go look at the stream on the trail near my home next time!
Wow--7C is warm for February in NB. Do check near the stream for stoneflies. If you have some wood so walk in, check there for spiders and scorpionflies, especially on snowy days.
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