So it appeared that the first group of birds used the only information available to them—the smell to which they had been exposed at the first site—and therefore oriented in the wrong direction. On the other hand, the second group, having the advantage of the more up-to-date and relevant olfactory information, chose the right direction. This was ingenious, but it did not satisfy everyone. Critics of Papi’s theory have carried out similar “false release site” experiments, in which they exposed pigeons to nonsense, artificial odors at the “false” release site—odors that could not have provided them with any useful navigational information. They found that these birds were just as well oriented at the actual release site as controls exposed to the real, local air. They briskly concluded that “olfactory exposure provides no navigational information to pigeons whatsoever.” In their view, the smells, whether nonsense or real, serve only to alert the birds to the fact that they are somewhere strange, thereby triggering some completely different navigational system; they do not supply any other navigationally useful information.