By: Kara Tyler-Julian | Biologist
In the forgotten back corner of a suburban yard, many small weeds are sprouting, overlooked by the homeowner who is otherwise occupied. These small weed sprouts are spotted, however, by a family of small rodents. The movement at the back of the yard attracts my attention and I notice this mother and her two little ones grasping the weed sprouts in their tiny front paws and delicately plucking them from the ground by their roots. They would then contentedly consume the entire plant- roots and all before moving onto the next sprout.
The “weed” was the native wildflower Bidens alba, better known by its common name of Spanish needle. It can be quite aggressive where it is allowed to spread thanks to its prolific seeds that stick to the clothes or fur of any creature that passes. This scene occurred about one year into our adventure of gardening with native plants to support wildlife and it was clearly working! However, I wasn’t yet familiar with this species of rodent that was lending me a hand in tending my garden. Being ever the studious biologist, I had to immediately identify this organism and discover its origins, life history, and behavior. Was this a native Florida creature, or one of the hundreds of invasive animals plaguing our ecosystems by no fault of their own? After all, it is humans who have introduced these many exotic species to our state where the animals are then forced to carve out an existence in a foreign land motivated only by their instinct to survive. Perhaps invasive isn’t a fair term to describe these creatures but rather “misplaced” might be more fitting.
After photographing and observing the creature I conducted a search online. I concluded based on the physical appearance of the “hispid” coloration and the way that the rodents hopped rather than scurried that my new friends providing the free weed control were the native Hispid cotton rats (Sigmodon hispidus). I was overjoyed to know that these were native rodents finding a home in my garden, rather than one of the invasive species of rats that can cause damage to human structures and spread the plague. The hispid cotton rats are omnivorous with a healthy preference for leafy greens, i.e. herbaceous vegetation, such as the young Spanish needle sprouts that they were eating. Hispid cotton rats can be found in a wide range of habitats but seem to prefer grassy areas with some shrubby overstory, which is what our yard was at the time. In the pine flatwoods areas their population can vary from 2 to 47 rats per hectare and usually have a home range between one half to one acre, which meant that this small family was likely the total population in our yard and the neighboring lots. The invasive rat species tend to make their nests on or in human structures and present in much higher numbers of individuals, so this small family of respectful native rodents was a much-preferred sighting.
The hispid cotton rats are one of the native species of wildlife that have been found sheltering in the burrows of gopher tortoises. They are a food source for many native predatory birds, snakes, and even panthers. Being a small, ground-dwelling prey item means that they are also vulnerable to attack by non-native feral and outdoor house cats. Indeed, the presence of house cats in our outdoor environments presents a severe threat to our native wildlife species including small rodents, birds and reptiles. A great way to help protect and support native wildlife in addition to planting native plants and conserving habitat is to keep all pets indoors and supervise them when they are outdoors in fenced-in yards. As their native habitat continuously shrinks, we must do everything we can to be respectful neighbors to the wildlife that we share our neighborhoods with.