Limpkins in Louisiana

Come for the seafood, stay to raise a family

Recently Jessa's cousin Rebekah pointed out a bird to me and asked what it was. Its appearance was distinctive, and despite never having seen one before—and despite not having expected to see one here—I was able to immediately identify it as a limpkin. (Does obsessively poring over bird books constitute a misspent youth?)

All of my field guides list Florida as the only place in the U.S. to find limpkins, but they were first seen in Louisiana in Lafourche Parish in 2017, just six years ago. The following year a breeding pair was documented in nearby Terrebonne Parish, and over the next few years reports continued to come in from these coastal parishes, where non-native Pomacea maculata apple snails had made an appearance in the mid-2000s. 

The invasive apple snails, notes non-game ornithologist Robert Dobbs of the Louisiana Department of Wildlife and Fisheries, were the key to these reported sightings and especially breeding records. Limpkins may have arrived with a storm, or under their own power, but they almost certainly would have left again without Pomacea:

They wander around naturally. They've wandered up the east coast in the past and around the southeast. Typically, when they show up out-of-range, they eat clams and other mollusks for a while, and then they leave. They generally don't persist in those odd places well outside of their core range. It's possible we had some birds wandering around and they happened upon the Terrebonne-Lafourche area, which is full of apple snails. So why leave? There's a ton of food. The habitat is good. Presumably the climate is okay. They've persisted thus far...

Persisted and spread, apparently. We saw our limpkin—and crucially, heard at least one other—at Irish Bayou in Orleans Parish. Bucks to beignets this ends up being another breeding locality for the newcomers.

A specialist uses specialised tools, and Jessa's photos—these are all hers, by the way—show a gap near the end of the bill, with the mandible tips crossing slightly. (Click to embiggen.) To extract an apple snail from its shell, the limpkin removes the operculum and extracts the snail with the forceps-like tip of the bill; when feeding on bivalves, the limpkin uses scissoring movements of the bill tip to sever the adductor muscles.

Even with these adaptations, however, limpkins are not a panacea for Louisiana's Pomacea problem. (P. maculata threatens both agricultural crops and native vegetation, and competes with crawfish as well as native snails). Robert Dobbs again:

At this point, there aren't enough limpkins to make much of an impact on the apple snail population. But if this trend continues and limpkins really do become established, it's possible that they could provide some level of bio control.

Meanwhile, birdwatchers such as ourselves can enjoy this recent addition to Louisiana's avifauna and the wild calls they add to the soundscape of the wetlands.