I’ve been known to joke that a useful “wetland indicator” is the presence of wood duck nest boxes. These structures are quite ubiquitous! I’d say the only nest structure more common in wetlands than wood duck boxes, is the classic sawed-off blue-plastic barrel (platform nest for geese, etc.). Anyway, wood duck nest boxes are placed (singly, or multiples) on metal poles in the marsh, or on trees in the forested floodplain. And yes, I’ve seen them in use—they really do work.
So, I was not surprised when I saw several Wood Duck nest boxes at a wetland in Grundy County. I was visiting Holland Marsh which seemed a natural choice for a guy from Pella, an employee of Central College (Go Dutch!). What DID surprise me was the variety in styles of the nest boxes and their placement. A duplex of two different steel canisters sat atop a steel pole along a meander in the floodplain of Holland Creek (photo above). Fun facts I recently learned about such “boxes” include that they were originally developed right here in Iowa, at Union Slough—one of my 99wetlands! Also, the canisters are typically emptied Freon containers…something I’ll ponder next time I use my air conditioning.
Nearby, behind a long angled berm, is a constructed marsh. There I found the other common type of wood duck nest box: an actual wooden box! This one had slipped down its mounting pole, so I could examine and photograph it. A typical example of the style, it was tall, with a wire mesh inside provided to allow a bird (fledgling) to climb up and out when ready to leave the nest. Although presently in disrepair, a box such as this can be reassembled and used again and again. But please consider the importance of keeping a nest box in good condition. Even a box appearing from the outside to be in perfect condition should be inspected and cleaned at the start of breeding season, and carefully monitored while in use. My observations suggest that too many nest structures (all over, not just in wetlands) are installed with good intentions but not subsequently maintained. An argument could be made that it’s counterproductive—a nest structure prone to predator or parasite problems might be an invitation to disaster for bird parents.
Kevin from the County Conservation Board suggested that perhaps the wood box is more popular with the ducks than the canister type—that seems to be the observations of others as well (see link above). In the battle of the boxes, old-school wood is still best! He also mentioned that routine maintenance of nest boxes is on the To Do list; hopefully that box gets on the schedule. As a cooperative of several conservation organizations (Pheasants Forever, Ducks Unlimited and Iowa Natural Heritage Foundation) work at Holland Marsh will have multiple objectives, in addition to promoting wood duck populations. I was delighted to hear, for example, that Blanding’s Turtles have been noted at the site.
I enjoyed walking around this wetland, enjoying its quiet beauty on a winter’s day. Thin, transparent ice showed the pondweeds beneath, and walking the berm provided a bird’s-eye view of the snaking, meandering Holland Creek. Although overcast, the wind was calm and a raptor soared around me, perhaps enjoying an even better bird’s-eye view. It’s fun to think about all the life still out and about, active all winter long. Perhaps I’ll find more of them…or their tracks, scat, and whatnot…in future wetland wanderings. I hope you’ll join me. Thanks for stopping by!