Spiders aren’t birds, but birders in Utah County who are heading out to enjoy fall migration need to be on the lookout for tarantulas. The western desert tarantula or desert tarantula (Aphonpelma iodius) is the only species of tarantula regularly recorded in Utah County – out of more than 800 species found worldwide – but these massive spiders can be an unwelcome surprise for unwary birders.
About Utah’s Tarantulas
Despite their fearsome appearance – with a hairy body and a leg span up to 4 inches – these spiders are relatively docile and are not known to attack humans or pets, though they can bite or may throw irritating hairs at assailants if they feel threatened. The bite will feel similar to a bee sting and while the venom is not typically toxic, dangerous allergic reactions can occur and anyone who is bitten should seek immediate medical attention.
It is most common to see tarantulas along desert roads in open areas in September and October, when males are leaving their burrows and seeking out mates. Females rarely leave the vicinity of the burrow, and any burrows that are found should be left alone, particularly if there is webbing or dead insects around the mouth which would indicate recent occupation. The western part of Utah County, including along Redwood Road south of Saratoga Springs, is a common area to see tarantulas in fall, with greater activity around sunset as these nocturnal arachnids venture forth. Unfortunately for birders without an affinity for spiders, this is also a prime time and location for seeing short-eared and burrowing owls or looking for migrating raptors, and it is always wise to watch where you step and avoid the edges of roadways to steer clear of tarantulas.
If You See a Tarantula
These large spiders can be easy to spot along asphalt and gravel roadways, but if you see one, don’t overreact. They will not jump or charge, and if you stay several feet away, the tarantula is likely to go about its business looking for insects or small lizards for dinner or seeking out a mate. Do not attempt to touch, capture, or harm the spider, and keep pets or children from investigating closely. And don’t forget, tarantulas are part of the desert ecosystem as well. More than one spider has provided a meal for a hungry American kestrel or other raptor, so watch them carefully and enjoy all the wildlife of Utah County.