Photo of a California Ground Squirrel who was busy gathering food for its winter snooze. They can be identified by their mottled fur containing a mixture of gray, light brown and dusky hairs. California Ground Squirrels can live up to 6 years in the wild. They give a high pitched alarm call to warn others of predators and are preyed upon by red-tailed hawks, golden eagles, coyote, fox, badgers, weasels, house cats, dogs, and snakes. #californiagroundsquirrel #groundsquirrel #squirrel #animal #outdoorphotography #wildlife #sepulvedabasin #sepulvedadam #sepulveda #lakebalboa #park #parkinglot #nature #cute #vannuys #scal #log #hike #walk (at Sepulveda Basin Wildlife Reserve) https://www.instagram.com/p/CF83eo_h3_g/?igshid=18jxslz7oodxl
Thanks to Arjun Roy on his interest on this next symbiotic relationship!
Take our next predator on the arid, grassland, habitat, the kit fox (Vulpes macrotis). Kit foxes are mostly nocturnal, but often active in daytime when it's cool weather outside.
They call underground dens their homes; their dens are multi-chambered with entrances and secret passage ways. Though kit foxes prefer to dig their own dens, sometimes they take the space of an existing ones; why reinvent the wheel, right? Sometimes kit foxes will find a den created by our unsung hero, the ground squirrel, and then tidy it up by enlarging the hole. Kit foxes will also reuse old dens made by; you think the fox rents month to month? Kit foxes tend to choose dens that are just big enough for them: small enough in diameter to exclude their own predators, the coyote.
A mother kit fox cleans here pup. Efren Adalem / Oohlookphotography.com
Let's talk specifically about the San Joaquin kit fox (Vulpes macrotis mutica), commonly found in the San Joaquin Valley and through much of Central California. The numbers for this subspecies are dropping steadily and are considered endangered; it has been on the Endangered Species list for nearly 50 years. Many scientists suspect the culprits to their decline are development- from building farms and houses, to cars and roads; others blame pesticides and outdoor poisons; others say their dwindling numbers are due to an explosive increase in their predators like the coyotes and competition for resources; and others blame climate change. Interestingly, decreases in their prey abundance caused by circumstances such as drought and too much rainfall result in decreases of reproductive success of kit foxes. Regardless, population numbers for the San Joaquin kit fox are not good.
The San Joaquin kit fox. Image by Mark A. Chappell
Learn more about the current status of the San Joaquin kit fox from this scientific paper
Hall, F. and Spiegel, L., 1986. Distribution and habitat requirements of the San Joaquin kit fox in the northern extreme of their range. Transactions of the Western Section of the Wildlife Society, 22, pp.60-70.
http://www.wildlifeprofessional.org/western/transactions/transactions_2007_5.pdf
Bring in our hero, the ground squirrel. Just like the burrow owl, not only does the kit fox relies on ground squirrels for a source of prey but they also rely on them to help create new homes for themselves and their young. Kit foxes occupy soils with a high clay content where they can modify burrow dug by other animals, such as ground squirrels.
However the ground squirrels are in trouble too. The use of pesticides to control rodents and other pests also threatens both the ground squirrel and the kit fox, either by directly through poisoning or indirectly through reduction of prey abundance.
Historically, measures such as hunting and rodenticides have been used to control rodents and reduce conflicts with livestock. This has greatly decreased the populations of these species, reducing prey availability for their predators.
Photo from https://sites.google.com/site/sanjoaquinkitfoxtp2015/feeding-habits
This relationship demonstrates the message that we all need each other to survive; either friend or enemy. What's that cliche saying? Keep your friends close, but your enemies closer. Maybe think about this in a science nature sense.
What to do with Squirrel Ph.D.s in Ecosystem Engineering
Burrowing Owls with their trademark white unibrows and yieldingly yellow binocular, beady eyes make the headlines this week, thanks to Omar Kazmi! who suggested we shine a spotlight on the raptors’ partnership with something of an underdog, the California Ground Squirrel.
POST BY: Alexandra Parvaz
Among the world’s smallest birds of prey or raptors, Burrowing Owls measure up to 10 inches in body length with a wingspan of about 2 feet and are possibly the most difficult to NOT anthropomorphize and sling some kind of caption to any and all their facial expressions.
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Unlike other owls and for that matter all other raptors that nest and roost in trees, these head-bobbing critters strictly live in tunnels or burrows underground. However, rather than build their homes themselves, they almost exclusively rely on dens built by Prairie Dogs and Ground Squirrels. These rodents are called fossorial mammals since they specialize in digging out burrows and mostly live underground. They are also called Ecosystem Engineers or Keystone Species, which despite their relatively small population sizes significantly affect the survival and existence of many other species, and play a huge role in determining the overall vegetation makeup and soil conditions that define a given ecosystem. And this captures…my response.
While they don't share the same burrows, more often the owls take over abandoned squirrel burrows and live alongside the ground squirrels or prairie dogs, offering their fossorial allies some protection from other predators...even as the Burrowing Owl eats it’s allies, too. Why waste too much energy for home and food when you can find it all with a squirrel?!
Hunting for the next generations.
Since they are most alert in the daytime and Diurnal, another contrast from the rest of the owl family that is usually Nocturnal, they hunt primarily at dawn and at dusk for an array of creatures that they can snatch up in their claws. They may swoop down and pounce on small rodents, frogs and snakes, chase after and ensnarl a frenzied lizard on foot, or catch insects like moths or small birds like sparrows in mid-air with one or two clean chomps.
Given their hunting and flying habits, they PREFER and reside in open low-vegetation valleys and treeless marshlands. All across western North America and Florida, from Canada through Mexico and the Caribbean to South America, these owls have been iconic residents in dry grasslands, agricultural and arid rangelands, as well as golf courses, cemeteries, airports and even near busy interstate highways.
A weird and yet special (save for the shameless go-pro advertisement) owl dance-off in Mary Lopez’ front lawn.
It would appear that these squishy owls fancy land types that, seemingly to their benefit, are quite common in a heavily urbanized world. Nonetheless, their populations are in decline as urban industrial humans compete rather aggressively for the same prime habitat. Much of their favored lands and the burrows they find left by squirrels are razed over for intensive agricultural purposes or leveled under buildings. In human-built environments like airports or grassy knolls near highways, another problem they may face is that the plants introduced there may end up being too tall that it hinders their ability to hunt. Pesticides used to control grasshoppers or other insects considered pests also pose huge health threats. But even more dangerous to the owls are the many ground squirrel or prairie dog eradication programs that in effect are wiping out the population of borrowers so critical for owl nesting sites. For these reasons, burrowing owls are Endangered in Canada and several U.S. states, Threatened in Mexico and considered a “Species of Concern” throughout the Rocky Mountain West and California.
Although these owls are protected under the Migratory Bird Treaty Act that prohibits selling, capturing, or directly killing them, we lack enough protective measures to secure more habitat that is safe from further urban development in the long-term.
Seeking to re-stabilize and build up healthier population levels, several conservation scientists, state officials and passionate bird advocates are working together to educate the community and developers to create more nesting sites for the birds. In San Diego County, California, the San Diego Zoo Institute for Conservation Research has been monitoring the efficacy of artificial burrow sites and how well existing and or new pairs of birds adopt them.
A prototype of an artificial burrow.
An even more exciting effort, though, is the translocation of the sacred California Ground Squirrel to select grassland sites from other areas where they’ve been captured so that they can naturally create new bonafide burrows for the raptors. Many of these new sites are areas that for decades have been disturbed by cattle, agriculture or other development projects.
Picture taken in 2011 as researchers released one of the near 350 squirrels in San Diego County as part of San Diego Zoo’s Conservation program.
Some of these squirrels are collected from eager-to-cooperate landowners who want nothing more than squirrel-free property, providing a win-win situation. With the squirrel’s voracious appetite helping manage the surrounding vegetation and it’s knack for digging out tunnels to Burrowing-Owl standards, these bushy tailed wizards may also create conditions that over time restore native plants and animals that have declined after years of former cattle-grazing. Although the translocation project seems to be making some progress, however, scientists still face some challenges with making the squirrel stay put in their new homes and saving them from being the ‘popcorn-catch’ of hawks and coyotes.
With a greater appreciation for the Burrowing Owl’s dependence on the Ground Squirrel, and implementing easy ways we can live alongside one another in the urban environment, hopefully, these critters can burrow evermore.
