One group of birds is relatively scarce in the lowlands of South Asia: insect eaters. A study published in Ecology Letters may explain why. Weaver ants—forest-dwelling ants that live in the lowlands and ferociously prey on small invertebrates—might be gobbling up the birds’ food source and pushing them to higher elevations.

“That’s a big-time idea, that it’s ants that shape insect-eating bird communities,” says School of Biological Sciences Assistant Professor Ben Freeman. He added though, while it’s an intriguing pattern, he would like to see future work test the hypothesis experimentally.