Let’s say we have an island with two endangered species living on it. This situation isn’t hard to imagine. Lots of islands have their own endemic native species that are very often endangered. Most island jurisdictions do all they can to protect their endemic wildlife.
But here’s the twist: Let’s say it has been determined one of those endangered species might be a major factor for mortality in the other endangered species. What do you do?
Well, we do have a real case in which one endangered species is harming the population of another. On San Clemente Island, the local subspecies of the island fox is preying upon an endangered subspecies of Loggerhead Shrike.
In the 90’s, it looked like the San Clemente Loggerhead Shrike was on its way to extinction.
Because the foxes are also quite endangered, there was little that could be done to reduce fox numbers.
However, a plan was devised and implemented in 1998 to solve the fox predation problem. The first part of this plan was to trap the foxes and hold them until the shrike breeding season was over. The second part involved the building of an electric fence around the shrike nests.
But the third part of the plan was the most novel.
E-collars have been part of dog training for a very long time. These collars are often employed to keep dogs from running deer and to generally control predatory behavior. A similar collar is also used as an invisible fence to contain dogs to their owners’ yards.
It was decided that these collars could also be used to train the foxes to leave the shrikes alone. The foxes were trapped and fitted with e-collars that could be activated when they approached an antenna sensor. It was the invisible fence to protect the shrikes. If a fox approached the trees where the shrikes were nesting, it got shocked. (These foxes, like their mainland relatives, can climb trees to raid bird nests.)
When this three pronged plan was implemented in 1998, the shrikes had a successful nesting season, and no foxes had to be killed to save the shrikes– thanks to a little “shock therapy.”
(In case you didn’t know, island foxes are native the Channel Islands off the coast of California. They are very closely related to the more common gray fox.)
Nice. A long-term solution would be to induce a taste-aversion in the foxes. This may not be practical, since it would require the sacrifice of some shrikes for the training.
Taste aversion conditioning (in canids, at least) has to be done by triggering nausea (which can be done chemically). A shock doesn’t do it. What the foxes have learned is a location aversion.
I use the same tools, and the same idea, with client dogs who won’t leave the cat box alone. Ideally we just put the cat box somewhere the dog can’t get it, but that’s not always feasible.
I caution the clients that if they move the cat box, the training has to be repeated to instill a new location aversion.
Now that would be interesting.
They have learned location aversion, which is useful in this case because the shrikes use only a selected stand of trees.