"Do You Like My Hat?"

"Why?" you may ask, "is that jay perching on that deer's head? And why doesn't she knock it away with a flip of her ears?" The answer is mutualism. Mutualism is a long-term interaction between two different species that benefits both. Think Finding Nemo: the clownfish sheltering within the sea anemone. One gets protection from predators while the other receives nutrients.

 

Unfortunately, our cute little Bambi friend hosts a harmful parasite—the deer tick. What we're seeing in the picture is a prime example of mutualism. As the scrub jay forages for its tick dinner, the deer receives pest control.

 

Although Monterey County is a hotspot for several varieties of tick, the most common is the Pacific Coast Tick (Dermacentor occidentalis). These ticks use multiple hosts. They feed on rodents as subadults and on cattle, horses, deer, and humans as adults. The Western Blacklegged Tick (Ixodes pacificus) also feeds on deer as adults but prefers moister habitats than our typical chaparral provides.

 

The California Scrub-jay (Aphelocoma californica) combines a beautiful azure blue head, wings, and tail, a grayish back, and white underparts. Scrub Jays are quite plucky and have been observed stealing acorns from woodpecker caches. Along with primates and dolphins, they are believed to be among the most intelligent animals. Studies have shown that they plan ahead for the future, a trait associated with higher intelligence. It is perhaps this combination of brains and audacity that led to such an unusual symbiosis.

 

And what do the deer get out of the deal? As the name suggests, the California Mule Deer (Odocolleus hemionus, subspecies black-tail) exhibits large, mule-like ears. The male has branching antlers, which divide into main beams, each forking into tines. The number and health of tines is dependent on age, genetics, and nutrition. A mature buck with a heavy tick load may be unable to grow symmetrical antlers. The pathogenic load leaves less energy available for antler development. And to a fawn, tick infestation can be fatal. Ticks covering their faces and ears can weaken or blind them making an already vulnerable animal an easy target.

 

According to the Cornell Lab website, "You might see California Scrub-Jays standing on the back of a mule deer. They're picking off and eating ticks and other parasites. The deer seem to appreciate the help, often standing still and holding up their ears to give the jays access."