Saturday, February 06, 2010

I am NOT a Mouse!

Okay, I know I'm cute, I get that, but please don't think I'm a mouse. (Smelly pesty little rodent...) Au contraire, I'm a "fastidious, beautiful animal" and "hardly deserve the negative stereotype most people have" of my kind. And that's according to the Colorado expert on such things. Photo credit: National Park Service.

When The Husband called me to look at a little critter jumping in and out of the chicken feed bucket late last month, I leaped to a quick conclusion. Despite my hasty conviction that the little guy is a Woodrat, I'm open to corrections.

Historical Perspective: Back in 1877, while hunting dinosaurs near Morrison, Colorado, Arthur Lakes preferred the outdoor life:
For myself I still adhered to my tent life & adjourned every evening to my canvas dog tent pitched by the side of the stream. At last however after one or two snowstorms it became rather dismal to leave the warm stove and go out through the snow to the cold tent & so I cam in & for the first night slept on the floor but the mountain rats kept up such a racket that sleep was impossible. So I turned my tent into a swinging hammock & swung myself up into the rafters above the boys head.

In annotating this journal excerpt for a local publication, I wrote:

Bushy-tailed Woodrat (Neotoma cinerea)
Lakes' "mountain rat" is likely to be the bushy-tailed woodrat, better known as the packrat of western lore. Of some 20 species of woodrats in the west, five [six*] occur in Colorado. The other 15 species occur mostly in Mexico and Central America, where some subspecies are considered endangered.

The bushy-tailed woodrat, as its alternate name implies, is best known for its acquisitive habits. The Mexican woodrat occurs in southern Colorado and extends its range northward through our area, taking advantage of the milder microclimates provided by the hogback and adjacent foothills. The larger, more common bushy-tailed woodrat occurs well into the mountains and ranges from Alaska to Mexico. Woodrats eat a variety of plants, preferring the leaves, quantities of which are stored in crevices for winter use. Woodrats generally nest among rocky outcrops in vertical cracks, caves, or shelves, although they also use old mines and outbuildings, as Lakes discovered.

*According to my favorite mammalogist, there are six species of woodrats in this state: Mexican, gray, white-throated, eastern, desert... (I can't figure out his sixth from that article, and don't have his book handy.) Most sources I found neglected to distinguish among—or provide a scientific name for— the species, but here's a Colorado list, courtesy NatureServe:

White-throated Woodrat Neotoma albigula
Bushy-tailed Woodrat Neotoma cinerea
Eastern Woodrat Neotoma floridana
Desert Woodrat Neotoma lepida
White-toothed Woodrat Neotoma leucodon

Other sources do list a gray woodrat, the Southern Plains Woodrat (N. micropus), so that or the white-toothed may be the sixth species in Armstrong's list. I'm guessing these little guys are tough for a novice to tell apart.

Meanwhile, back to Our Story:
As you can tell from the previous post, it took several tries before we were able to capture this little fellow at all clearly (window and screen notwithstanding). Mostly my shutter finger was not quick enough. I got several nice photos of the empty bucket, though.

But as he traveled back and forth from the feed bucket to the stash many times, we were finally able to catch him going in... and out of... the bucket. He was quick!

(The feed bucket is 9.5 inches/24 cm in diameter. Armstrong says the smallest Colorado species of woodrat is 12 inches/30 cm long. Is he including the tail? I can't imagine a local rodent more than 12 inches long, except rock squirrels and marmots. Anyway, bigger than a mouse, for sure.)

We weren't the only ones appreciating the show! The cats, trapped behind glass, enjoyed it even more!

The first personal encounter I recall with woodrats was a sad one many years ago. A woman, startled by the appearance of this creature in her brand new foothills mansion, captured it in a glass canning jar and brought it to the museum where I worked at the time to get an ID. Without punching holes in the lid. Horrified, I told her what the freshly suffocated creature was, but was not nearly as welcoming as I would have been with most visitors. An educational opportunity lost: I suspect she never set foot in the place again!

For some time, we've known that woodrats occupied the peripheral spaces of the chicken coop. Sometimes I even see (more often, hear) them in the ceiling or under the floor when I collect eggs and count beaks each evening. Occasionally one of the cats leaves a half woodrat on the doorstep. Last week, the entire ceiling of one part of the coop collapsed, exposing a collection of mummified lilac twigs complete with leaves, chewed foam panels, nesting material, and a vast accumulation of waste material. We were on our way to a veritable packrat midden.

Yes, woodrats, aka packrats aka trade rats, particularly in the southwest, are benefactors to humankind. Their middens, one of which is pictured here, are archeological time capsules that record vegetation, climate (via pollen trapped therein), and other conditions dating back as far as 40,000 years! Being fastidious, as Armstrong says, they deposit their refuse in discrete areas, where it accumulates to form deposits that are almost geologic in scope. Cemented and preserved by crystallized urine, the mass is capable of preserving most anything in it and, thus, a boon to researchers. More on this photo.

Our woodrat continues to live under the front step, where I hope he will elude the cats, live long, and prosper. He still enjoys sunflower seeds and chicken scratch, although to date he's shown no signs of leaving us any shiny baubles in return.

More on woodrats:

Nice writeup on the Colorado species of Neotoma.

At Wikipedia (see also species pages and links)

Species of concern, on Univ. of Calif Santa Cruz campus, which has some good photos of the "stick-pile" nests they build when not living in rocky cliffs. We saw a lot of these in the deserts of Arizona.


Okay, it must have been a really lousy photo. I'm awarding the prize to Swampy, at Swamp 4 Me, who at least got it to the right Order (Rodentia). Thanks, everyone, for chiming in! Swampy, send me your address to claim your original historic postcard of this fabulous local spot where you can see packrat middens.


Ellen Rathbone said...

Well, of course! Now that we know what we are looking at it is easy to see a small mammal in that original photo! Not a piece of leaf lettuce after all!

Sally said...

Ellen, it was a good guess, and I appreciate your playing-- that's actually a reflection of a grape ivy leaf from inside the house!

Thanks for checking back!

Allison said...

Thank you for your nice web site. This enabled me to identify the 'huge mouse' that took up residence in my garage during the floods last week in Boulder. We finally ran them out. Stinky but awfully cute. Have enjoyed learning about them since!