What black ducks really eat

greg setter

greg setter

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View attachment IMG_20181130_215045.jpg
These are not seeds, they are little snails. Black ducks eat more shellfish than anything else in the salt marshes along Delaware Bay. I have found them full of little mussels, snails like this, a few sea worms, and sometimes some plant seeds. Blacks are stronger in flavor in the salt than mallards, although when I used to hunt fresh water I didn't really notice a difference in taste. I thought some of the inlanders here would be interested in this.
 
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The gizzards of the gadwalls we shoot on Mobile Bay are full of snail fragments.
Our grassbeds are full of snails, I think the gaddies eat more snails than vegetation.
Same for all our divers too.
 
I've noticed a lot of snails in some saltmarsh black ducks in R I, and I've also noticed a stronger than normal flavor in some. I'll have to start checking the crops more regularly. I have not been getting as many blacks as I used too--I attribute this to the numerous oyster farms; there is a lot of worker and boat presence close to where they used rest and spend the night--this happens daily until the boats are frozen out. This seems to bother even buffleheads and mergansers; they used to spend a lot of time in areas which now have wall to oyster farms wall to wall on the shallow water of the south side of Ninigret pond. I often see close to a dozen boats and 20 workers in a half mile area!
 
Black ducks along our Sinepuxent Bay generally eat the same, more animal matter than plant matter up to and includeing minnows. My normal waterfowling haunt is about five miles inland and during a bay freeze some of those birds come inland looking for fresh , open water. You can always tell, just from odor when you,ve brought one of the transplants to bag during those periods. Huge difference between the blacks hanging out in the river swamp as compared to bay marshs. But even on the fresh they,re found loafing around gravel bars where small fresh water mollusks are abundant.
 
Good morning, Greg~


Yes, our coastal Black Ducks eat mostly animal matter.


On Long Island, they pick Saltmarsh Snails (Melampus) in both the intertidal Cordgrass (Spartina alterniflora) and the high marsh Salt Hay (Spartina patens). We have opened crops (proventriculi) with over 700 Saltmarsh Snails in them.



View attachment sm Bio 13 - Saltmarsh Snails.JPG



On the falling tides, they dig feeding pits on the flats and creek bottoms. They dig with their feet and sift the sediments with their bills to find food. The next tide cycle pretty much erases these pits.


View attachment sm Bio 18 - Feeding pits.JPG





The principal food items here are Duck Clams (Gemma) and Sand Worms (Nereis ?). The worms live within these tubes of glued-together sand particles.


View attachment sm Bio 20 - BB 22C.JPG





When times get tough - as in late winter - they will resort to Ribbed Mussels and Killifish - and acquire a less palatable flavor, to say the least.



All the best,


SJS

 
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Good thing about the black duck is that you get red meat and shellfish all at once. A fantastic adversary!
 
Mr. Black is a true duck hunters duck! Don,t find him sitting on the local shopping malls storm water pond as that ol gaudy mallard will do. First I shot this year was a couple weeks ago and the drake pure blk. duck came in with a mallard hen. Guess he was getting revenge for all the Drake Mallard / Blk. hen match ups!
 
They definitely zero in on the snails. As a sidenote, don't they get the sarcocystis/rice breast parasite from those snails? Or periwinkles?
 
Good morning, SJ~


I do not know the life cycle of Sarcocystis or the role of snails. A quick Google search simply showed me that it occurs in lots of species, including lots of mammals (a serious problem in horses, I gather). Anybody know the other hosts in those species of Sarcocystis that cause rice-breast?


We see it not uncommonly up here in freshwater country - especially late in the season when the diet is probably pure aquatic invertebrates because nearby fields are covered with ice and snow.


All the best,


SJS





 
Steve,

I mentioned it because I remembered seeing snails described as the primary vector to the ducks, in a paper years ago which I can't locate now. I did a little more research on the web and see repeated mention of snails and other unspecified invertebrates in the parasites lifecycle, but also that the larvae may be free-swimming and they, or eggs, may be ingested directly. Regardless of how the duck contracts it, the rice breast looks pretty nasty to me!
 
On the rice breast, some years we see it a lot, and some years not so much. I've seen it in pintails and black ducks mostly, but also in GWT. One year I shot 7 pintails, which is quite a few for my area, and 5 of them had it. But this year, it's been so slow, I'm not sure I'm going to need to worry about it. I do wonder how many ducks that I roasted whole and never saw the meat until it was cooked had it though......
 
We see ducks with rice breast every so often here in Utah, especially with birds that have been feeding on the Great Salt Lake which is rich in brine shrimp. Prime candidates here are shovelers and pintails. In 12 years of duck hunting I've only ever run across it 3 or 4 times thankfully, it's freaky looking!
 
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