Predators on the Reserve

Coyotes are a well-adapted species of the Canidae family that can be found in many parts of North America ranging from cold, mountainous terrain to low, dry elevations. At the Merced Vernal Pools and Grassland Reserve, Coyotes are the largest land predator, preying on California Ground Squirrels and other small rodents and birds as well as anything else it can find. Coyotes are also largely opportunistic and there have been reports of berries and plants found in their feces when more substantial food such as meat is scarce. Coyotes tend to be solitary but can be seen in small groups and often communicate to one another through howling and yipping at night.

Two species of eagle are found on the UC Merced Vernal Pools and Grasslands Reserve. Bald Eagles are in the sea eagle family and fish is a main part of their diet but also scavenge and feed on carrion. Golden Eagles tend to be more terrestrial and like the Coyote, primarily hunt medium sized rodents such as California Ground Squirrel and Cottontail Rabbit, using speed and their large hooked talons to snare their prey.  Golden and Bald eagles mate for life and build large nests in trees or cliffs to rear their young.

California Ground Squirrels are known as a keystone species. This means that its presence greatly affects and influences other species. Burrowing Owls use old squirrel holes to nest in and amphibians like toads or the endangered California Tiger Salamander use burrows to escape the heat of the mid day sun. So not only do Ground Squirrels provide food for the predators on the reserve, but their homes are also important to other species for survival.
These species interactions are always in motion. On July 2nd I observed a coyote catch a ground squirrel from where it was drinking at the stock pond behind the barn. This was quite an experience because it is not common to catch predation in action. But it is always a possibility to see these important keystone species and if one is lucky they can see these predators in this diverse and interconnected habitat.


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Report by Katharine Cook

August 6, 2015