a little wild   (a small slice of wildlife)

what	when	where	pic
garter snake: probably eastern garter snake, thamnophis sirtalis	2010-04-02	moose hill audubon sanctuary, meadow
trashline orb weaver, cyclosa conica	2010-04-02	moose hill audubon sanctuary, off trail

April 2, 2010 was a chilly day, more winter than spring. I’m not sure the wildlife around here knew that.

We went for a walk at Moose Hill Audubon Sanctuary with our friends Sarah and Mike. Akash was excited: guests to play with, and the first hike of the season. We chose not to go on the summit trail, instead going on a level path that took us to a grassy meadow.

Our first noteworthy encounter was with this little spider (a few mm):

It’s a trashline orb weaver, Cyclosa conica. Charming name, isn’t it? They implement vertical stabilimenta in their webs, as do many other spiders (note the thicker strands of the web in the lower picture). As far as I know, the debate over the purpose of these has not been resolved. But most trashline orb weavers go a step further and enhance their stabilimenta by adding litter into the web (the litter is often debris from insects they have killed). They then sit themselves in the center of the web in a small gap between the upper and lower lines of trash and are difficult to resolve, so it seems clear that in this case at least the purpose is as camouflage for themselves. For some reason, however, the one that we saw did not have a trashline. Just created the web and didn’t have time yet? Too early in the year? Don’t really know.

I’m impressed that it was out this early. As mentioned, it was definitely a cold day, and spiders are of course cold-blooded. How do they get their metabolism working? Does getting out in the sun play a role? I believe that this specimen was out in the sun, but it was in the woods and it wouldn’t be possible to find a spot that would consistently be in the sun over much of the day. I have read that many Linyphiids may be found actually walking around on the snow in the middle of winter — I’m impressed and puzzled.

Note that the web does not appear to have a hole in the center like the orchard spider does: http://picasaweb.google.com/lh/photo/bu0c67gyrmyuMlKJloEnpw?feat=directlink. What does this correlate to? The type of prey? They seem to live in similar environments, why would their prey be different?

The key to identifying this species, of course, is their bumpy little butt. Very distinctive and very distinguished. Truly a great tush.

Our next friend was a garter snake, Thamnophis sirtalis.

If you look at the pattern of scales, it seems pretty similar to that described on http://www.umass.edu/nrec/snake_pit/pages/cgarter.html, which would make it a common garter snake; in particular, an eastern garter snake, T. sirtalis sirtalis. As it was early April, it was probably just emerging from brumation, which is similar to hibernation except that the snakes are not asleep, but merely in state of reduced metabolism.

After arising from brumation, a young garter snake’s mind runs to thoughts of love. The males emerge first, so as to be ready to compete when the females emerge. There are many more males than females, so competition is intense. We only saw one garter snake, but were informed by other families that there were others out there. The action is centered around each female, so it would have nice to have been able to find one — cherchez la femme! Interestingly, garters are ovoviviparous — they give birth to live young. Often, viviparous reproduction has been associated with enhanced maternal care for the young — I do not know if this is true in this case.

Wikipedia (http://en.wikipedia.org/wiki/Common_Garter_Snake) says that the females store the sperm and use it when required. Interestingly, some females mate in autumn, before brumation, but if these females mate again in spring the spring sperm overrules the earlier load. This leads to lots of questions: is there a cost to the male for mating in autumn? Is there an advantage to the female? Why does the mating in spring automatically overrule the mating in autumn? Is it because mating in spring is more competitive, so the males who successfully mate in spring are more likely to be healthy? Given the preponderance of males, it seems clear that any female would be able to get as many mates as she needs in spring, so why does this practice persist?

Most of the photos of the snake were taken by me lying down in the grass. This seemed to provoke the garter into seeing the camera as a threat, perhaps another male. It came close, raised its head, flicked its tongue in and out, and moved its head from side to side: is this a threat ritual? I don’t have many talents, but one of them seems to be the ability to provoke animals to threaten me (it’s happen several times with spiders).

In the following photos, note the prominent nose. I wonder how good their sense of smell is, or if they can sense infrared like some other snakes.

Finally, we saw a large rock and just had to tip it over to see what lay beneath. Here’s the photograph. I don’t think it requires any further words of explanation. Enjoy.

We carefully placed the rock back and felt that spring was off to a good start.