The abbreviations for species are stored in the Taxon table in the Recorder 6 database, and in the Index_taxon_name table, but they aren’t all populated for names made up of 2 or more words, some are wrong and for many birds, but not all, the 5-character abbreviation has been replaced by the 2-character BTO code. Hence resqu will find Red Squirrel on the lists where the common name is Red Squirrel but not on lists where the common name is Eurasian Red Squirrel (abbreviation eured). The abbreviation for harlequin duck is hq so haduc won’t find it. Hrlad is the abbreviation for harlequin ladybird but it should be halad. The last time I checked the abbreviation field wasn’t populated for user added species.