This taxon is Not Recognised as a species by BirdLife International.
Oceanodroma castro (Sibley and Monroe 1990, 1993) has been split into O. castro and O. monteiroi following Bolton et al. (2008). All Oceanodroma species have since been moved to Hydrobates (del Hoyo and Collar 2014).
BirdLife International (2016) Species factsheet: Hydrobates castro. Downloaded from http://www.birdlife.org on 03/12/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 03/12/2016.