Kestrel and Cotton Rat

I was stuck on traffic-jammed Bobby Jones Expressway in Martinez, Georgia the first time I ever saw a kestrel.  The brave feathered beauty nailed a cotton rat in the grassy median just yards from passing cars.  It’s quite amazing to witness predator-prey interaction in the middle of urban civilization.  I have since seen these diminutive falcons on several occasions, and they always appear to be hunting cotton rats on grassy roadside rights of ways.  Most people don’t realize  there is a healthy population of cotton rats in Georgia, living in the grassy areas along roadside ditches.

Male kestrel.  They’re much more colorful than the females.

Note how small a full grown kestrel is.  While perched on a telephone wire, they could easily be mistaken for a songbird.

Female kestrel.

Kestrels are so small, it’s possible I’d seen them long before my encounter on Bobby Jones Expressway, but perhaps just never noticed them.  They mostly hunt large insects, especially grasshoppers and dragonflies, and small mammals, but they also take lizards, snakes, frogs, and birds ranging in size from humming birds to mourning doves.  Cotton rats are rather small rats, but kestrels will prey upon larger non-native Norway rats and also weasels.  Kestrels often ambush bats exiting caves.  Excess meat is stored in clumps of grass where the falcons will return to feed.  The preferred habitat of the kestrel is forest edge that gives them access to hollow snags for nesting and grassy fields for hunting.

The American kestrel (Falco sparverius) is closely related to the common kestrel (Falco tinnunculus) of Eurasia, and genetic evidence suggests the 2 species diverged during the late Miocene from a common ancestor.  Pleistocene-aged fossils of American kestrels are fairly common, including one specimen found in Kingston Saltpeter Cave in Bartow County, Georgia.

Audubon kept a young kestrel as a pet after he found it had fallen from its nest.  He successfully reared it, and the bird learned to hunt on its own.  This led to its downfall.  Nero (the name Audubon bestowed upon the falcon) made the mistake of attacking some newly hatched chicks.  The mother hen rushed to their defense and pecked the little kestrel to death.

Cotton rat (Sigmodon hispidus).  Quite common in the southeast.

Cotton rats favor early successional habitat–grassy clearings and overgrown fields, thus explaining why they’re found on roadside rights of ways.  Highway maintenence workers keep highway medians in a permanent state of early successional habitat by frequently mowing the grass.  Cotton rats eat green vegetation, especially stems, leaves, and seeds.  They also consume insects and probably quail eggs.  They breed rapidly: gestation is just 27 days, and the females come into heat immediately after giving birth.  This rapid rate of reproduction explains how their populations can explode and provide food for a plethora of predators.

Photo I took of a naive young cotton rat at the St. Mark’s Wildlife Refuge in Florida last June.  It was not afraid of me at all.

Cotton rats are very common in the Pleistocene fossil record, and their ancestors likely originated in South America.

Tags: cotton rat, Falco sparverius, kestrel, Sigmodon hispidus