C. teauteensis is considered valid, based on the argument that as with many New Zealand birds, it is reasonable to assume that North and South Island populations were at least distinct subspecies, if not species. But even though Kálmán Lambrecht mentioned a putative holotype tibiotarsus (which still exists in the BMNH) he explicitly stated that Forbes' names were both invalid. In addition, harrier bones of comparatively recent age in the collection of Walter Mantell, assigned to C. gouldi (an obsolete name of C. approximans) by Richard Lydekker, seem to be of a more robust bird judging from the published descriptions; this material may now be lost, but all things considered it is not unlikely to be the first remains of Eyles' harrier known to science.
C. teauteensis is deemed valid, considering that like many New Zealand birds, it's reasonable to assume North and South Island populations were at least distinct subspecies, if not species. However, even though Kálmán Lambrecht mentioned a potential holotype tibiotarsus (which still exists in the BMNH), he explicitly stated that Forbes' names were both invalid. Additionally, harrier bones of recent age in Walter Mantell's collection, attributed to C. gouldi (an obsolete name for C. approximans) by Richard Lydekker, appear more robust based on published descriptions; this material might be lost but is unlikely to be the first known remains of Eyles' harrier.