Posts Tagged ‘winter’

February trapping

March 9, 2012

I traveled to Portal again Feb 18-20, this time meeting a crew of people from New Mexico State University.

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Chaetodipus pencillatus, desert pocket mouse.

Karen Mabry has been especially helpful for finding volunteers and keeping Portal going through our lower-funding times. She also studies rodents, with most of her work with Peromyscus at the Quail Ridge Reserve in California. So she was excited to see that diversity at the site is returning quickly–we’re back up to 10 different species!–and that we caught several incredibly cute cactus mice (Peromyscus eremicus). We also continue to catch the harvest mice (Reithrodontomys megalotis and montanus), which was fun for visiting grad student Katie Smith, who studies the endangered salt marsh harvest mouse in California.

Katie Smith holds a small harvest mouse. Photo by J. Smith.

With so many experienced rodent-trappers, we were able to get through all the captures pretty quickly and leave extra time in the afternoon for Jane Smith to take some measurements for her project. Also an NMSU grad student, she has been investigating the effects of small mammals on soil organic carbon, using the experimental manipulations at our site.

I’ve never captured so many birds before, but 11 of our 110 traps this month has birds in them rather than rodents! Pictured above is a white-crowned sparrow (photo by J. Smith). These were most common, along with black-throated sparrows and a canyon towhee.

Katie Smith, Kristin DaVannon, Sarah Supp, and Karen Mabry (left to right) process the rodents from the exclosure plots. Photo by J. Smith.

(Above) Kristen, an undergraduate student at NMSU, learns that handling rodents is fun! Photo by J. Smith.

The winter plant census is fast approaching, and many flowers were already beginning to bloom in February! I’m optimistic that it will be another beautiful spring. Keep posted for the plant update!

escholtzia mexciana

Poppies are already in bloom! Photo by J. Smith.

Lupinus coccinus.

January trapping update

February 14, 2012

One of the best things about working in the desert (especially when you’re doing long-term ecology!) is that things are always changing. After the recent drought, we saw a decline in biodiversity at the site that rivaled anything seen throughout the course of the 35 years of study, including the dominance of the rodent community by a very small-sized species (Desert pocket mouse, Chaetodipus penicillatus) which surprised us all. After some decent rains in 2011, diversity is slowly returning to the rodent community as we have been seeing more of the generalist species return. These species seem to be more transient at the site, popping up when conditions are right for them. I was still a bit surprised, however, to catch several plain’s harvest mice (Reithrodontomys montanus) in January! This is a species that I hadn’t seen in a few years, so it took me a moment to determine what I was seeing.

Another of the generalist species that has been popping up this winter is the cactus mouse (Peromyscus eremicus). We even found a nesting pair in our trap shed this past month! They were pretty cute, but since our trap shed has recently been inundated with other living things–pack rats and most recently, at least one rattlesnake and a badger living underneath the shed, I chased them out. I really don’t want the shed to seem like a larder for our resident rattlesnake. Pictured below, is my volunteer of the month, Loren Sackett, from University of Colorado at Boulder.

Loren studies prairie dog populations, genetic divergence and pathogens in the southwest. You can read about her adventures at the prairie dog blog.

Meanwhile, the rain seems to have slowed from earlier in the winter but the plants are still growing! We’re headed down to the site again in March to have another rodent-trapping-plant-field-extravaganza.

Above, Rumex, Erodium, and Guterrezia all green up. The vegetation at the site seems hard to categorize and we’ve had trouble finding just one or two field guides to use when we do the plant surveys. Luckily, over 25 years of work at the site has led to the compilation of an amazing  mini-herbarium of pressed plants and identifying characteristics that we can bring down with us when we do our plant surveys. I’m currently working to update this herbarium and have found several websites that are also really helpful for plant identification in the area, such as this NMSU website, this Arizona wildflowers website, and this New Mexico flora website. I’d love to hear any other suggestions of websites or books that are helpful for plants in the Portal area–please share!

Seed pods from Devil’s claw (Proboscidea parviflora) on the fence of a rodent exclosure, Chiricahua mountains in the background.

It was pretty small, but I’ve never seen a tarantula in January before!

Loren sets traps at sunset.

 

Holiday season with the Portal rats

December 21, 2011

Trapping at Portal is usually done on the weekend closest to the new moon. This is done for a number of reasons: 1) trapping at the same time each month lends consistency to our methods, and 2) evidence suggests that rodent may be most active outside of the nest under the cover of the darkest time of the month (but then again, maybe not). This year, the new moon fell on the day after Thanksgiving and again on Christmas Eve. As much as I enjoy handling rodents, I pushed back the monthly Portal trips to the first (Dec 2-4) and third quarter (Dec 16-18) of the lunar calendar.

When the temperatures drop, many of our smaller species disappear for the winter as they enter torpor to save energy and remain warm in their burrows. Although larger species, such as the kangaroo rats and grasshopper mice stay active year round, they are still susceptible to cold desert nights, which commonly dip as low as 20 F in the winter! Getting wet, even a little bit, when it is so cold can kill even these larger individuals. So when I arrived in Arizona on Dec. 2nd to see rain clouds in the sky,  I knew that trapping that weekend was just not going to happen.

rainy Portal road

Given the total lack of rain last winter in southeastern Arizona, and the nasty fire season they experienced this past summer, the rain is much needed. So although we weren’t able to set out traps, Tim Bean, visiting from UC Berkeley (where he studies the endangered giant kangaroo rat!), helped me with some site maintenance activities.

Erosion around the gates in our fences has continued as the rain falls, so we took advantage of the damp soil to rebuild little ‘ramps’ for the rodents to use to ensure that immigration and emigration from fenced plots can still happen.

While walking around all the plots, we also filled in holes that seemed to go under our fences. Here, a badger has successfully created a superhighway into one of our total rodent exclosure plots, right under the bottom of the buried wire mesh.

Here, Tim valiantly fills in the hole. Not a very good substitute for getting to see cute kangaroo rats, but it had to make do.

Germination has already begun, and if the rain keeps up, there should be a lot of vegetation this spring!

For the second December trip, I brought along ASU researcher with the CAP LTER, Julie Ripplinger, and we were lucky enough to be able to set traps one night, despite rain clouds lurking in the sky.

Julie is pictured here holding a cactus mouse (Peromyscus eremicus), which seem to be relatively abundant right now! We caught nearly all of them in pairs, one trap right next to the other and nearly all were in breeding condition. Cactus mice may breed year-round if conditions are right. They are also quite pretty mice with their orange-y sides, large ears, and very soft fur.

In addition, we continue to catch a solitary Bailey’s pocket mouse (Chaetodipus bailey); the species that was once our most dominant seems to be hanging around nearby…

Rain clouds hung around all day on Saturday (Dec 17) so we erred on the side of safety and didn’t set traps on our final night. Instead we completed more plot maintenance, this time focusing on stabilizing our trap shed. The shed is one of those snap-together plastic outdoor sheds which works fine for our purposes, but from time to time begins to fall apart and needs snapped back together. During the past two weeks, something dug a large hole underneath so it was completely destabilized. I wanted to take it completely off its cobbled-together rock base and rebuild it, but Julie stopped me when she saw the tail of a mojave rattlesnake poking from underneath the shed near my hand. Again deciding to err on the side of safety (snakes often overwinter in large groups, called a hibernaculum), I satisfied myself with carefully filling in the part of the hole I could see and stabilizing the roof of the shed.