Any birdwatchers who do a lot of paddling on the wilder rivers of Florida should check out these two websites:
Listen to the latter's recordings of the IBW's so-called "kent" calls. They don't sound to me like "kent." Rather, they sound like a soft, old-fashioned auto's bulb horn.
Also study the way that IBW's remove bark from recently dead sweetgums and spruce pines. It is pretty distinctive.
The Choctawhatchee River is not the only river in FL with a lot of mature floodplain forestland.