Summer World_ A Season of Bounty - Bernd Heinrich [30]
I saved the torn-apart wasp nest left over from the raiding ravens, and wanting to put it to good use, I wondered what our vireos (there is a pair near our house every summer) might accomplish with a superabundance of wasp paper. Might they plaster the whole of their nest with paper? I made three bundles of the paper by wrapping wire around it and hung them in the trees near the house. The vireo sang vigorously in the summer, but I found no nest until it was revealed after the leaves came down in November. I eagerly retrieved it, and to my surprise it had about the same amount of wasp paper as many of the other nests I had seen. Do vireos, after having incorporated a little bit of wasp paper into their nest, then find that their strange urge is satisfied?
In the next year our neighbor, while sitting on her porch in a thunderstorm in July, was suddenly attacked by a wasp that went for her eye. She suffered swelling down to her chest. After she located the nest I offered to help her get rid of it, and at night I went with a net I had made of wire mesh that was large enough for wasps to get through easily, but this mesh was covered with gauze that the wasps could not get through and that I could remove later. I scraped the rim of the net along the top of the nest to try to get it to drop into the net, and I had a piece of cardboard with me to slip over the net, in case the nest really did drop in, as I hoped. I would then, still at night, transfer the captured wasps in their nest into my (now nearby) raven aviary, where the wasps would settle down to rest. Later, still in the dark, I would remove the outside gauze, and in the morning the wasps would all be at their nest in the aviary.
The results showed that ravens respect wasps: the transfer of the wasp nest appeared to be a success; in the morning the wasps were flying into and out of the nest. No raven went near it. But gradually there were more wasps leaving the nest than coming back. After two days there were no more wasps at the nest, and the ravens then destroyed it and ate all the larvae and pupae with gusto.
Word then got out that I wanted wasp nests, and another neighbor offered a wasp nest that was under her porch. I tried the same approach, except that this was a much larger nest and it just barely fit into my net—and then, to my displeasure, I failed to get the cardboard seal over the top. In seconds after I dislodged the nest, dozens of wasps leaked out, and as I made a run for it my hands and arms felt as if they were on fire from the many stings. I flung the open net with the wasp nest into the back of my pickup, jumped into the cab, slammed the door shut, and spun off down the driveway. Later, back home in the dark, I maneuvered the nest into the aviary. As before, the wasps gradually left. After they had all cleared out, the ravens again destroyed the nest and ate the contents.
Although it would have been satisfying for me to get experimental results proving that the vireos’ paper nest decorations indeed repel blue jays, chipmunks, red squirrels, and crows, negative results would not have proved that the origin of the paper is unrelated to that function. That’s because the proximate results are not necessarily coupled to the ultimate results. It is possible that the paper on a vireo’s nest now serves no useful function, and is more like our appendix, indicating to a previous function