Collecting at Canyon Trail Park 4/10/17

Our first trip to Canyon Trail Park (El Cerrito, California) of 2017.

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It was a nice sunny day today after a rainy and windy week and the season has just started for much of the wildlife around here. We decided to take our first 2017 trip to Canyon Trail Park to see what we could find. We mainly had in mind the three local swallowtails, Battus philenor hirusta (pipevine swallowtail), Papilio rutulus (western tiger swallowtail) and Papilio zelicaon (anise swallowtail) since their host plants are all very abundant there (pipevine, willow, and fennel, respectively). When we got there, we slowly made our way through the trail scanning all the plants, starting with the willows. We didn't find much except for a few western tussock cateripillars (Orgyia vetusta). Next we headed to the fennel, but most plants were small and smothered in all the other weeds there so we couldn't find anything there either. Finally, we made our way to the pipevine, which grows very vigorously at this time of year, but the leaves were completely uneaten and there was not a single egg cluster on any of the vines. We did, however, see several pipevine swallowtails flying along the trail and high up in the trees. Though the butterflies themselves are out, it seems that it is probably slightly too early for them to lay eggs, as the weather has not warmed up quite as much as it should be at this time of year. 

Since we didn't have any luck with the swallowtails, we decided to move on and just look around the place for anything else that might be there. Historically, we have found many European mantis (Mantis religiosa) oothecas along the wooden fences around here, but they were always already hatched. However, this time when we looked on the fences, we found two egg cases, one small and clearly open (the case was damaged and the zipper was a mess), but the other one was very large and looked completely perfect in condition and unhatched! The zipper was completely sealed and it looked much cleaner than all the open egg cases we have found in the past; the coloration even looked a bit darker. We eagerly removed and collected the unhatched ootheca from the fence. 

When we brought the unhatched ootheca home, we compared it to all the open oothecas found in the past and weighed them all. Sure enough, the one we found today was much heavier, at 0.7 g, while the others hardly registered on the scale, only weighing 0.2 g at the most. Hopefully this ootheca will hatch soon so we don't have to care for it too long and risk it dying. The ootheca we had last year had already hatched on 4/1/16, so it probably won't be long for this to. 

While along the trail, the most abundant insects there were by far the damselflies and dragonflies. Dozens, maybe hundreds, were flying around the hill and along the creek. Most of the smaller ones looked like vivid dancers (Argia vivada) and other common damselflies. However, there was a very large red dragonfly in the mix that we decided to catch. Based on the coloration, it looks like a male red skimmer (Libellula croceipennis), though Odonata is not our expertise. 

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​Authors
Alan Liang

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