It is so easy to walk by small things in nature – either unseen or simply not understood.
While on a field excursion to Elmer’s Island, near Grand Isle, with a Louisiana Master Naturalist of Greater New Orleans workshop, we were discussing the ecology of the lagoon behind the barrier island. We noticed some little piles of crumbled seashells along the water margins, and began attempting to identify the source.
I earlier mentioned finding similar clusters on Grand Isle, but with more form – seemingly shell pellets. As we found more, someone suggested a bird had eaten the mollusks and pooed them out. This seemed plausible, except that there was no fecal material, nor form, to the piles.
It seemed more likely that birds consumed the shells, identified as coquina or bean clams (Donax variabilis), ground them in their crops, swallowed the clam meat, and regurgitated the shell fragments.
But how could we be sure? We needed evidence.
We soon found a pile of shell fragments, and about six inches away, a pile of feces. Hmmm. Our hypothesis became that a bird urped up shells, then defecated. The distance between the two piles was about the body length of a willet!
Willets were common in the area, and we watched them closely. Finally, we saw one flexing as if regurgitating something, and we moved toward it. As good luck would have it, we found a pile of shell fragments and a pile of feces, with willet footprints in between – toes facing the shells! Proof positive, in my humble opinion.
These observations also confirmed our opinions back in 2011 that the shell pellets were regurgitated by willets.
The nice thing about field trips to natural habitats is that one often learns the basics of how critters live.
A small pile of crushed bean clams (Donax variabilis) found on Elmer's Island in Aprl 2015. Photo by Bob Thomas.
The suspect, a willet feeding along a beach. Photo by James Beck.
|The first clue was a pile of crushed bean clam shells about a willet body length from a pile of bird poo. Photo by Bob Thomas.||The clinching evidence - a willet stood facing the left, erped out a pile of crushed bean clam shells, then pooed in releaf. Photo by Bob Thomas.|
Here a couple of friends were enjoying a meal together, and ridded themselves of the after effects before flying away. Photo by Bob Thomas.