A burrowing owl?
Sort of. It is a useful misnomer since something more accurate like ‘the burrow-inhabiting owl’ doesn’t have quite the same ring. These animals, with their seemingly paradoxical name, could be mistaken for a character in a Dr. Seuss book but can be found in the San Diego area and are a species of special concern in California.
During my time as an environmental consultant, I have conducted burrowing owl surveys in Southern California as part of several large utility projects. The surveys aim to detect the presence or absence of the owl. If present, mitigation measures can be implemented which attempt to prevent work activity from disturbing, and potentially displacing, this unusual owl.
Although this is a bird that lives underground, some of its behaviors could make this seem like the least interesting aspect of its life history. For example, it is one of many bird species that have been observed using tools. For the burrowing owl this tool is cow dung. It will collect the dung and scatter it around its burrow which attracts dung beetles. The resulting dung beetle buffet can be an important food source for a burrowing owl. In addition to this, the burrowing owl has learned to mimic the warning sound of another burrow inhabiting animal, the rattlesnake. If a predator is lurking outside the burrow of an owl, the owl can create a hissing noise that predators will mistake for a rattlesnake’s hiss/tail rattle. Like most humans, most animals would rather avoid an encounter with a rattlesnake and will usually find another burrow to investigate.
The burrowing owl suffers from the same conundrum as snakes in that it lacks the appendages necessary to create the burrows it requires. This means it must rely on other burrowing mammals to provide for them which, in the case of the western burrowing owl that lives in San Diego, is primarily the California ground squirrel. As a result, the fate of the western burrowing owl is directly linked to the presence of a species that is considered a pest. If ground squirrels are extirpated from an area, burrowing owls will likely follow.
Like most species suffering from declining numbers, the causes are usually multiple. The burrowing owl requires open grasslands where it hunts for small mammals and invertebrates during early mornings and evenings. Anyone who lives in San Diego can likely attest to the fact that an open grassland is not something you commonly see in your city. Historically the burrowing owl was found in many areas of San Diego County, but due to development it is now primarily restricted to a corner of Otay Mesa.
Luckily, the plight of this grumpy looking animal has attracted the attention of many conservation groups, and mitigation measures including trimming tall grasses in open areas to create a more natural habitat, the construction of artificial burrows, and translocations are all ongoing and seem like a promising path forward in ensuring that the burrowing owl remains a San Diego resident.
Levey, D.J.; Duncan, R.S.; Levins, C.F. (2004). “Use of dung as a tool by burrowing owls” (PDF). Nature. 431 (7004): 39. doi:10.1038/431039a. PMID 15343324.
Rowe, Matthew P.; Cross, Richard G.; Owings, Donald H. (1986). “Rattlesnake Rattles and Burrowing Owl Hisses: A Case of Acoustic Batesian Mimicry”. Ethology. 72 (1): 53–71. doi:10.1111/j.1439-0310.1986.tb00605.x.
Photo Credit: By Brian Lohstroh
William Roberts