The Search Continues

During the last few weeks, I have spent all my time trying to find prairie dogs.  A simple task in Boulder, it has proven to be tricky with the shier Gunnison’s prairie dog (Cynomys gunnisoni), which live in less densely populated colonies and do not clip vegetation the way that black-tails (C. ludovicianus) do. Because of these two life history traits, they are much less conspicuous, and can be difficult to spot even when you know you’re at a colony.  Furthermore, plague seems to be taking a heavy toll on populations at the edge of the Gunnison’s prairie dog range– dozens of people pointed me to colonies that had existed within the past few years, and I arrived to find only unmaintained, unoccupied burrows.

Above: Prairie dog researchers at a site that is slowly recovering from plague.

Plague is not the only threat to prairie dogs.  In many places, prairie dogs are seen as pests and are poisoned continuously over large areas.  Eliminating several populations near each other decreases the likelihood that they will be able to recover, because empty colonies can not be re-colonized from nearby animals.  The processes of extirpation (extinction of a single population) and re-colonization are known as metapopulation dynamics.  In a metapopulation, a series of populations function together, so that when one dies, it can be rescued by individuals from another population.  However, when many local populations die out simultaneously, there are no source populations to rescue those that have gone extinct.  This can lead to contraction of a species’ range, which may be what is happening to Gunnison’s prairie dogs.

Black-tailed prairie dog in Boulder County, Colorado.

Nonetheless, after much searching and asking expert opinion, I was guided to a small colony in Springerville, AZ.  In colonies with low population density, deciding where to set up traps is of the utmost importance.  Prairie dogs are trap-shy, and will avoid traps if they can.  Before attempting to catch any, we bait the traps and hold them open so that the animals can get used to getting free food out of the traps and be less apprehensive about them.

This black-tailed prairie dog is not trap-shy.

While my frustration at setting traps in 50+ mph winds mounted, various signs of life reminded me how much fun field work is, particularly in prairie dog colonies:  because they build burrows, their colonies are home to many other critters that share the burrows– lizards, rattlesnakes, rabbits, burrowing owls, toads, wyoming ground squirrels and more.  Prairie dogs also aerate the soil and move nutrients to the surface where it is more available to plants, so they can increase plant diversity in an area.  They also attract predators such as hawks, coyotes and ferrets.  Their colonies are therefore places of high species diversity– this is one reason to be concerned about prairie dog declines: many other species would also decline in concert.
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An assortment of species found on prairie dog colonies is pictured below. L-R and top-bottom (entomologists, please help!): beetles in prickly poppy, Great Plains yucca (Yucca glauca), grasshopper, prickly poppy (Argemone sp.), Hooker's evening primrose (Oenothera elata), scarlet globemallow (Sphaeralcea coccinea), caterpillar, desert plume (Stanleya pinnata), Wyoming ground squirrel (Urocitellus elegans).