Students get unexpected lesson in the food chain

 
By Mark Spreyer
Stillman Nature Center
Posted6/8/2018 12:53 PM
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  • A large bullfrog at Stillman Nature Center in Barrington recently demonstrated how the food chain doesn't always work the way we'd like it to.

    A large bullfrog at Stillman Nature Center in Barrington recently demonstrated how the food chain doesn't always work the way we'd like it to. Courtesy of Karen Lund

Do you feel sorry for a worm slurped down by a robin, or a crayfish gobbled up by a raccoon? Probably not.

Now, let's turn the table. Instead of a warm-blooded, feathery bird eating a coldblooded fish or worm, what if a coldblooded creature eats a warm-blooded, baby bird?

Well, it happened here at the nature center in front of a group of fourth-graders

Late one May, fourth-graders from a nearby school were on their field trip to Stillman. As is our custom, we divided the group in two. Half start with a walk and then do pond study while the other half starts at the pond and then walks through the woods.

As I was bringing the first group to the pond, a pair of startled wood ducks took off leaving their newly hatched chicks behind. All but one of the ducklings headed east, but one dumb duck hung around.

As the fourth-graders reached into the water with dip nets, the wood duckling headed our way. Sure enough, he came on shore and the students were very excited to see the little guy. I told the kids that it would be best if "junior" joined his siblings back in the lake.

So, I picked him up and headed around the building to our other dock. Here, I ran into the other half of the school group that was about to trade activities with my group.

I explained the situation, released the wayward duckling in sight of its nestmates and the children then headed back to finish up with the first pond study class.

A couple of minutes later, the second group arrived, and did they have a predatory story to tell. Shortly after I left the duckling to find his mates, a large bullfrog found "junior." The frog came from under the duckling and swallowed it from behind. As one of the chaperones explained it to me, the last thing that was seen was the head of the peeping duckling being pulled under by frogzilla.

As you might imagine, this graphic demonstration of the food chain had an impact on the audience. Here's a sampling from the students' thank you letters:

"That little chick was cool until it got eaten."

"The funniest part of all, and sad at the same time, is [sic] when the bull frog ate the baby duckling ..."

"I really enjoyed everything. I learned about the food chain (even though you didn't plan to teach us that)."

Actually, I did. For obvious reasons, though, I'm more likely to talk about plant-eating ducks and bug-eating birds then puppy-eating alligators and bird-eating frogs.

As you can tell, this incident gave me a chance to revisit the food chain. Specifically, as Thomas Tyning wrote in his guide to amphibians and reptiles, "Don't be shocked if you see a bullfrog going after 'unfroglike' meals. They are known to eat ... fish, snakes, birds, and other frogs ..."

I was also reminded that nature shows no favorites, warm-blooded or coldblooded, and has no mercy. As naturalist and essayist John Burroughs wrote, "Nature is not benevolent; Nature is just, gives pound for pound, measure for measure, makes no exceptions, never tempers her decrees with mercy, or winks at any infringement of her laws."

• Mark Spreyer is executive director of the Stillman Nature Center in Barrington. Email him at stillnc@wildblue.net.

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