Birds in the News

Table for Two

The discovery of Brown Jays foraging on a sloth’s hairy coat raises questions about the animals’ relationship.

A rolling stone may gather no moss, but the opposite is true for Costa Rica’s three-toed sloth. These creatures move so slowly that over the course of one’s lifetime, it gathers an entire ecosystem on its back: fungi, algae, moths, beetles, ticks, mites, flies, and more. The sloth’s guests help it in a whole host of ways: When the moths die, they act as fertilizer for the fungi, which in turn feed the algae. The algae isn’t only nutritious sloth food (it’s rich in lipids!); it camouflages the sloth, too—protecting it from airborne predators.

The sloth’s fur also provides a plenty of food for the cloud forest’s Brown Jays, according to new findings published this month in the journal Frontiers in Ecology and the Environment. Kelsey Neam, a graduate student at Texas A&M, was in Central America to study the sloth’s spatial ecology when she noticed a trio of Brown Jays hovering nearby One of them was foraging for food in the sloth’s coat, and the sloth, Neam writes, “appeared to be unfazed.”

She captured the jay’s snack-attack on video:

Brown Jays have been known to eat everything from insects and spiders to lizards, frogs, and wild fruits, but this is the first time one has been seen finding its food in a sloth’s body hair. It’s still unclear what exactly the Brown Jays were eating, but Neam observed the phenomenon twice (and her colleague saw it once, confirming the sighting). The particulars will make a big difference when it comes to characterizing the relationship between the bird and the sloth, Neam writes. If the bird is eating the moths, for instance, it is depriving the sloth of its algae supply and possibly making it more vulnerable to predators—not a good thing. But if it’s feasting on parasitic mites and ticks—the service African oxpeckers provide for zebras and rhinoceroses—then Neam’s discovery could be the start of (research on) a beautiful friendship. 

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