Look what cropped up

• Photos

Dissection Of A Mallard Gizzard

A ducks gizzard is the large digestive organ that grinds up food. By taking a look inside you can get a snapshot of what these birds are eating.

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A Duck’s Dinner

Ducks swallow sand and small pebbles to help grind up seeds, bugs, and other plant parts that they digest.

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As you are laying out in the marsh, watching clouds roll by, waiting for the next batch of ducks to come into sight, do you ever wonder what they are looking for?

Why would a Mallard want to land right here? Do the decoys look “real”? Is it my amazing ability to mimic a seductive hen’s voice? Does that patch of corn or weeds look like an amazing buffet that is just too good to resist?

Well, like many questions that I ponder in the marsh, there probably isn’t one clear cut answer. Granted, a good stiff wind will aid in the motion and “realness” of my decoys. I could always improve on my calling skills. And depending upon a variety of factors the ducks may be looking for one type of food over another. As to which detail is more important at any given time, we will probably never really know.

Opportunistic diners

Waterfowl by nature are opportunistic creatures. The fact that they migrate thousands of miles to take advantage of seasonally flooded resources is proof of that. Another indication of the opportunistic nature of these birds can be done by taking a closer look at the digestive system and what they dine on. Ducks don’t have a true crop, but they do have extra storage capacity in their esophagus so they can cram a lot of food in during a short period of time and then take flight before becoming dinner themselves. The next organ is the crop, proventriculus is the more technical term, which starts to break down food items. Bugs deteriorate quickly here and may not make it to the gizzard, which is the next organ. This part of the bird is very muscular and essentially grinds up tougher foods, like seeds, with the help of ingested sand and pebbles.

Depending upon the season, availability, and the energetic needs, a Mallard’s diet will vary. Typically, early in the season moist soil seeds provide the energy and nutrients needed to sustain these birds. As conditions become harsher, “hotter” foods such as corn or acorns can provide the carbohydrates or energy that these birds require.

What were they packing?

Last week after a successful hunt I decided to take a look to see what the Mallards at Duck Creek had been dining on. After breasting out the birds, I examined the esophagus and crop within the duck's neck. This portion was clear of food, so apparently the birds I harvested had been roosting prior to being shot.

Continuing my search, I cut into the large, hard gizzard. Amid the gravel and grit, these birds had eaten a ton of dark round seeds with flat sides. These seeds belong to a species of smartweed, that grew up on Duck Creek despite the lack of management due to the ongoing construction. Nodding smartweed germinated in many of the hunting pools in Unit A and could have been seen in late summer with a long cluster of white flowers that droop or “nod”, hence the name. Their seeds are slightly smaller than another common smartweed, known as the Pennsylvania smartweed. Both are high in protein and contribute to a balanced diet for migratory waterfowl.

Most of the birds I harvested that day had nodding smartweed seeds in their gizzards, but one drake contained the larger Pennsylvania smartweed seeds. Perhaps he had spent a day down at Otter Slough or jumped over into a different habitat patch over at Mingo for a dinner the night before. Who knows…once again I find myself with more questions than answers.

Well, the next time you have a successful day out in the marsh staring at the sky, questioning, and shooting. Take a closer look at your harvested birds; who knows what will crop up.