"Precursor" is a controversial prehistoric bird genus from the Early Eocene. It was established based on fossils found in England, e.g. in the famous London Clay deposits. Three species have been named, but the supposed "genus" seems to be a chimera composed from remains of different and quite unrelated Neornithes.
At least some of the remains seem to belong to a sort of psittaciform, of which today various parrots and cockatoos exist. Initially, it was even supposed that the fossils belonged to some family that is still extant. By now, it seems more likely however that the psittaciform material of the "Precursor" paratype belongs into the Pseudasturidae (of which Halcyornithidae may be the correct name). These were either basal in or immediately outside the Psittaciformes, and looked more like puffbirds in habitus though they were almost certainly not at all closely related to the latter. True parrots probably originated in the approximate region of Australia or perhaps neighboring Antarctica and did not reach Europe until less than 30 million years ago.
Unfortunately, it is unknown what the affiliations of the holotype material are. The fact that it was originally perceived to be something similar to a pratincole or courser suggests that the revised taxon Precursor may belong into the Charadriiformes. Certainly the Glareolidae are an ancient lineage, possibly originating more than 60 million years ago. If the "charadriimorph" remains are indeed Glareolidae, they should already be rather autapomorphic.