In fact, published studies referenced below found in Louisiana's coastal master plan denote how critical SAV prevalence is to gadwall prevalence. Yep, ask US how we know after the little experiment that was the 2023-2024 waterfowl season in our (too) saline marsh. Even after tropical systems we have SAV in our interior ponds, but last year even the most interior were zapped, not a sprig hardly to be had.
Gadwall are more dependent on submerged aquatic vegetation (SAV) than many other dabbling ducks (White, 1975; Leschack et al., 1997; Hartke et al., 2009). Plant matter makes up 95-97% of the diet on the wintering grounds (Leschack et al., 1997). The occurrences of gadwall in different marsh types are probably tied to nearby SAV. White (1975) found that foraging was most common in areas with 70-100% SAV coverage. There was little use of areas with less than 30% SAV coverage. In Louisiana, the diet is comprised of algae, dwarf spike rush (Eleocharis parvula), widgeon grass (Ruppia maritima), Eurasian water milfoil (Myriophyllum spicatum), and coontail (Ceratophyllum demersum) (Paulus, 1982).
Yea, we saw that.
But already this year, with a whole lot of growing season to go:
Scouted future Redhead Pond blind build site so I can get some pre-fab work going for that at my house soon. All pond flats surrounding it are covered in it. Then ventured to my favorite hole, our usual, and cleaned out blind there. Removed benches and took measurements for a bench install and probably will be doing a floor over top of this one. Also removed old brush from last season, and left the stuff that's growing. The ants falling out of all of it kept things interesting for sure.
The big ponds had plenty food coming along, and the important small potholes were pretty thick with it, which are places they go for hiding out and actually holding on the property. Long way to go with both growing season and of course tropical concerns, but looks really good for now.