Friday, September 28, 2012

Trackers at the Dipper Ranch

The Bay Area Tracking Club visited the Dipper Ranch on September 9, 2012. With about 20 people attending, we set off on a dirt road towards the Newt Pond and the Newt Spring to look for animal sign.

Curious trackers examine the evidence.
There were lots of deer tracks and some coyote and bird tracks, and we found two types of hairs caught on a strand of a barbwire fence about 8 inches above the ground. Coyote and a high-jumping rabbit, coyote dragging rabbit under the fence?

Canyon live oak twig nipped by a dusky-footed woodrat. These oaks were very tall which means the woodrat climbed up about 40 feet to get to the branch tips and then down again.
At the top of a steep ascent under the canopy of tall canyon live oaks, there were several twigs on the road. The  twigs were about 6 inches long, included both leaves and acorns, and had an angled cut on the end. This time of year, I frequently see twigs and partially chewed bay fruit on this part of the road, and have always assumed they were the work of sloppy squirrels. Random Truth pointed out that squirrels would take just the acorns and not bother to nip off the twigs. A critter that would collect both leafy twigs and acorns would be a dusky-footed woodrat. He described woodrats as busy collecting material to fill their larders this time of year. They climb up a tree, bite through branch tips, allow the twigs to drop to the ground below, and then climb back down the tree and gather up the twigs to carry to their stick nest. Random Truth has lots of good photos at his blog showing woodrats busily collecting and stashing twigs of all sorts.

The shed skin of a snake dangling inside a hollow tree.
At the Newt Spring, someone discovered the shed skin of a snake dangling inside of a hollow stump. Freaky! We cautiously peeked in and discussed whether the very long and banded skin was from a gophersnake, rattlesnake or kingsnake. I voted for gophersnake because the biggest snakes I see around the Dipper Ranch are gophersnakes, not rattlers (thank goodness!).  Some brave soul reached in and gently pulled the skin out of the hollow so that we could examine it more closely.

Examining a skin which shows the the scale patterns and faintly shows the coloration of the snake from which it was originally shed.
It had faint alternating dark and light bands of about one inch width. I was still guessing gophersnake when someone turned the skin inside out and to the gasps of all observers, suddenly the pattern was very distinct and definitely the somewhat flattened hexagonal blotches of a Northern Pacific rattlesnake. Not only did the inside of the shed skin show the original colors of the snake clearly, but it also showed the small keels rattlesnakes have on each dorsal scale. As we turned the head portion of the skin inside-out, the multiple small scales between the eyes were apparent (whereas gophersnakes have large scales between the eyes), and the slightly raised supraocular scales (we called them "eyebrows"because they are the scales above the eyes) popped up.

Turning the shed skin inside out, this is unquestionably the markings of a rattlesnake. The long scales to the right are the belly scales.
Factual Interlude - (Warning, this is where I get off on tangents in this blog and look up stuff until I find an answer to my "Why?" question and then feel the compulsion to share the answer because surely you must have the same question. You can skip this paragraph and get back to the description of the trapping day if you are not a compulsive "Why?" person like me.) Why would the inside of the shed skin have a darker imprint of the snake's coloration? After referring to my favorite snake book, Smithsonian's Snakes In Question, I've determined it probably has to do with how a snake sheds its skin. As it gets ready to shed, the snake produces a layer of new cells underneath its outermost sheath. The cells on the bottom side of the sheath die and dissolve thus separating, usually as one piece, from the new skin cells. The snake rubs its head against a hard object and loosens the skin at the edges of its lips which starts the process of the entire dead layer folding back against itself. With continued rubbing, the snake peels the old skin back from its head and then catches the loose flap against a rock or squeezes through a narrow space to pull the entire skin inside out and off its body. Thus when we picked up the shed skin, we were initially looking at the inside layer, the layer which dissolved to start the loosening process. When we turned the shed skin inside out, we were looking at the outside layer which although exposed to weathering of the environment, retains more of the coloring associated with the snake's pattern because those cells are thick and keratinous and do not dissolve as part of the shedding process. Who said snakes were boring?

A big skunk visited the spring several days before the tracks were discovered and a little skunk visited the spring the night before the trackers arrived.
Moving on, we checked tracks on the road near the spring. One set of tracks was approximately one inch long and consisted of five toes with nail marks (see links below for photos). Garth guessed these tracks were from a skunk. There had been a brief spattering of rain a few days earlier which made the road surface crusty and the prints somewhat indistinct. I kept my cheating mouth shut because I had just checked the photos on a wildlife camera that was mounted at the nearby spring. Once the group thoroughly examined and discussed the tracks, I whipped out a portable viewer and showed everyone what had showed up on the wildlife camera in the last few days: deer, bobcat, striped skunk. Garth was right.

Photo of the hole taken after I originally discovered it and several weeks before the tracking event. Possibly a badger dig.
At the end of our hike, we dashed up a steep hill above the orchard to look at signs of vigorous digging. I had first noticed these holes a few weeks earlier when I was standing in the kitchen door brushing my teeth and saw a series of three long and narrow fans of freshly thrown dirt. They looked different than the usual gopher mounds or coyote digs. It seemed like a lot of dirt had been moved in a precise manner in a short period of time. The Dipper coyotes are lazier than that when they dig, however, the coyote pups were dispersing, so it could be youthful coyote enthusiasm.

Scat found near one of the possible badger digs when I originally discovered them. It looks similar in size and shape to the scats I find near the summer coyote den.
Although they were not fresh, when we got up close to the holes, we noticed that all three were approximately eight inches wide, greater than a foot deep and two bent sharply to the side as they continued deeper. These were possibly badger holes as badgers are accomplished diggers and Random Truth says they often dig several holes right after another on the same grade. We looked for hairs in the entrances but found none. We did find one scat but were unable to determine whether it was badger or coyote pup. I have never seen a badger at the Dipper Ranch but one of my co-workers has and we have seen badgers or badger sign at Windy Hill, Russian Ridge and Skyline Ridge Open Space Preserves in the last few years. The trackers suggested I set up a wildlife camera on any fresh, similar diggings. I accepted the assignment and agreed to brush my teeth outside as often as possible.

The larvae of a California newt in the Newt Pond approaching the waving red threads of  bloodworms (midge larvae) which zip back into the mud when disturbed.
My fellow trackers posted more photos of the day and a video of the unusual bloodworm phenomenon at the Newt Pond here, here, and here.  The Bay Area Tracking Club meets the second Sunday of every month at Gazos Creek Road on Highway 1 (north of Santa Cruz, California between Ano Nuevo State Park and Pigeon Point Lighthouse). I expect to be joining them and I hope they will be visiting the Dipper Ranch again because trackers are a most curious group of adventurers.

We made casts of three tracks at the Newt Pond. I'll report on these later once I get more coaching on how to clean casts.
See Also:
Black-tailed deer, Odocoileus hemioanus columbianus
Coyote, Canis latrans
Bobcat, Lynx rufus
Dusky footed woodrat, Neotoma fuscipes
Northern Pacific rattlesnake, Crotalus oreganus oreganus

Pacific gophersnake, Pituophis catenifer catenifer
Striped skunk, Mephitis mephitis
American badger, Taxidea taxus
Canyon live oak, Quercus chrysolepis

Snakes in Question, The Smithsonian Answer Book. Carl H. Ernst, George R. Zug. The Smithsonian Institute. 1996. 
Rattlesnakes: Their Habits, Life Histories, & Influence on Mankind. Abridged Edition. Laurence M. Klauber. University of California Press. 1982. 


  1. You are right about the snake shed. You weren't turning it inside out, it was already that way. You were bringing the outside back out!

  2. I'm sorry I missed this, Cindy. I had written it down on my calendar, but then the weekend turned out busier than most. That's really interesting about the inside out shed skin. Say, do you have any posts about ring-necked snakes? I did a search of your blog and didn't find one.

    1. Katie: much later, here is a response. I do occasionally see ring-necked snakes at the Dipper Ranch and briefly mentioned them with a photo here:


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