CHANGES TO IBPAOU20.DBF (FROM IBPAOU20.DBF) BASED ON AOS (2021) This file documents all changes to species names and codes to IBPAOU21 (from IBPAOU20) performed in June 2021. These changes are based on changes to species and nomenclature as recorded in the 62nd Supplement to the AOS Checklist, made available online by the AOS in late June 2020. In all cases additions and changes were thoroughly cross-checked for new conflicts and for the release of old conflicts. Unless stated it can be assumed that no new conflicts occurred. NUMB, CAT, PNO, and ORD codes (species number, category, species status, and order) are internal codes used by IBP, in part to resolve conflicts (see Pyle and DeSante 2003, listed on IBP's alpha-code page for details). Changed: Falcipennis canadensis (Spruce Grouse) to Canachites canadensis, SPEC6 to CANCAN (from FALCAN). Inserted: Common Wood Pigeon (Columba palumbas) (after Rock Pigeon); NUMB=12513, CAT=2, SPEC=CWPI, ORD=1, SPEC6=COLPAL, ORD6=1. Re-arranged: 9 species among genus Chaetura as indicated. Changed: Calliphlox bryantae (Magenta-throated Woodstar) to Philodice bryantae, and C. mitchellii (Purple-throated Woodstar) to P. mitcheillii; SPEC6 to PHIBRY (from CALBRY) and PHIMIT (from CALMIT), respectively. Inserted: Amazilia Hummingbird (Amazilis amazilia) (after Mangrove Hummingbird); NUMB=08205, CAT=3, SPEC=AMHU, ORD=1, SPEC6=AMAAMZ, ORD6=2. ORD6 = 2 due to conflict of ORD6=1 code (AMAAMA) with that for Amandava amandava (see below). Inserted: Pallas's Gull (Icthyaetus icthyaetus) (after Franklin's Gull); NUMB=04605, CAT=2, SPEC=PAGU, ORD=1, SPEC6=ICHICH, ORD6=1. Changed: Mew Gull to Common Gull (Larus canus), NUMB to 04677 (from 04680), CAT to 2 (from 1), SPEC to COGU (from MEGU). Inserted: Short-billed Gull (Larus brachyrhynchus) (after Common Gull); NUMB=04680, CAT=1, SPEC=SBIG, ORD=2, SPEC6=LARBRA, ORD6=1. ORD=2 due to conflict with code for Slaty-backed Gull (see below). Changed: SPEC for Slaty-backed Gull (Larus schistisagus) to SBAG (from SBGU), ORD to 2 (from 1), CAT to 1 (from 2, as it now breeds sporadically in Alaska), due to new conflict with code for Short-billed Gull (see above). Changed: Phalacrocorax penicillatus (Brandt's Cormorant) to Urile penicillatus, P. urile (Red-faced Cormorant) to U. urile, and P. penicillatus (Pelagic Cormorant) to U. pelagicus; SPEC6 to URIPEN (from PHAPEN), URIURI (from PHAURI), and URIPEL (from PHAPEL), respectively. Changed: Phalacrocorax auritus (Double-crested Cormorant) to Nannopterum auritum, SPEC6 to NANAUR (from PHAAUC) and ORD6 to 1 (from 2); and P. brasilianus (Neotropic Cormorant) to N. brasilianum, SPEC6 to NANBRA (from PHABRA). Release of ORD61 code PHAAUR results in change in SPEC6 to Pharomachrus auriceps (see below). Inserted: Cinereous Owl (Strix sartorii) (after Barred Owl); NUMB=06955, CAT=3, SPEC=CIOW, ORD=1, SPEC6=STRSAR, ORD6=1. Changed: Pseudoscops clamator (Striped Owl) to Asio clamator, SPEC6 to ASICLA (from PSECLA); and P. grammicus (Jamaican Owl) to A. grammicus, SPEC6 to ASIGRA (from PSEGRA). Changed: SPEC6 for Pharomachrus auriceps (Golden-headed Quetzal) to PHAAUR (from PHAAUC), ORD6 to 1 (from 2) due to release of conflict for ord6=1 code due to change of genus for Phalacrocorax auritus (see above). Changed: Subfamily for Antillean Piculet to Picinae (from Picuminae). Sequence remains unchanged. Changed: Caracara cheriway (Crested Caracara) to C. plancus, SPEC6 to CARPLA (from CARCHE). Reordered: 69 Families in Order Passeriformes as indicated. Changed: Deltarhynchus flammulatus (Flammulated Flycatcher) to Ramphotrigon flammulatum, SPEC6 to RAMFLL (from DELFLA), ORD6 to 2 (from 1). ORD6 = 2 due to conflict of ORD6=1 code (RAMFLA) with that for Ramphocelus flammigerus (see below). Inserted: Pallas's Grasshopper Warbler (Helopsaltes certhiola) (before Middendorf's Grasshopper-Warbler); NUMB=14273, CAT=2, SPEC=PGWA, ORD=1, SPEC6=HELCER, ORD6=1. Changed: Middendorf's Grasshopper-Warbler (Helopsaltes ochotensis) to Middendorf's Grasshopper Warbler, SPEC to MGRW (from MIGW), ORD to 2 (from 1). ORD=2 SPEC needed due to conflict of ORD=1 code (MGWA) with that of CAT=1 species MacGillivray's Warbler. Changed: Regulus calendula (Ruby-crowned Kinglet) to Corthylio calendula, SPEC6 to CORCAL (from REGCAL). Inserted: Bahama Nuthatch (Sitta insularis) (after Pygmy Nuthatch); NUMB=13722, CAT=3, SPEC=BANU, ORD=1, SPEC6=SITINS, ORD6=1. Changed: Tropical Gnatcatcher Polioptila plumbea to White-browed Gnatcatcher Polioptila bilineata, SPEC to WBGN (from TRGN), SPEC6 to POLBIL (from POLPLU). Reordered: 11 species in family Polioptilidae as indicated. Inserted: Grass Wren (before Sedge Wren); NUMB=14118, CAT=3, SPEC=GRWR, ORD=1. Scientific name (Cistothorus platensis) and SPEC6 remain unchanged. Changed: Cistothorus platensis (Sedge Wren) to Cistothorus stellaris, SPEC6 to CISSTE (from CISPLA). Changed: Spotted Nightingale-Thrush (Catharus dryas) to Yellow-throated Nightingale- Thrush, SPEC to YTNT (from SPNT). Changed: Lonchura oryzivora (Java Sparrow) to Padda oryzivora, SPEC6 to PADORY (from LONORY). Changed: SPEC6 for Amandava amandava (Red Avadavat) to AMAAMN (from AMAAMA), ORD6 to 2 (from 1) due to conflict with newly inserted species Amazilis amazilia (see above). Changed: Estrilda caerulescens (Lavender Waxbill) to Glaucestrilda caerulescens, SPEC6 to GLACAE (from ESTCAE). Changed: CAT for Tricolored Munia (Lonchura malacca) to 2 (from 3). Reordered: 12 species in family Estrildidae as indicated. Inserted: West Mexican Euphonia (Euphonia godmani) (before Scrub Euphonia); NUMB=16987, CAT=3, SPEC=WMEU, ORD=1, SPEC6=EUPGOD, ORD6=1. Changed: Euphonia elegantissima (Elegant Euphonia) to Chlorophonia elegantissima, SPEC6 to CHLELE (from EUPELE); and E. musica (Antillean Euphonia) to C. musica, SPEC6 to CHLMUS (from EUPMUS). Reordered: 17 species in subfamily Euphoniinae as indicated. Changed: Amphispiza quinquestriata (Five-striped Sparrow) to Amphispizopsis quinquestriata. SPEC6 (AMPQUI) remains unchanged. Inserted: Chestnut-capped Warbler (Basileuterus delattrii) (after Rufous-capped Warbler), NUMB=16393, CAT=3, SPEC=CCAW, ORD=2, SPEC6=BASDEL, ORD6=1. ORD=2 SPEC needed due to conflict of ORD=1 code (CCWA) with that of CAT=2 species Crescent-chested Warbler. Changed: SPEC6 for Ramphocelus flammigerus (Flame-rumped Tanager) to RAMFLG (from RAMFLA), ORD6 to 2 (from 1) due to new conflict with Ramphotrigon flammulatum (see above). Inserted: St. Kitts Bullfinch (Melopyrrha grandis) (after Puerto Rican Bullfinch), NUMB=17483, CAT=3, SPEC=SKBU, ORD=1, SPEC6=MELGRA, ORD6=1. Other Changes Inserted at request of a user: Hawaiian Duck X Mallard Hybrid Anas wyvilliana x platyrhynchos (after Hawaiian Duck); NUMB=01645, PNO=2, CAT=2, SPEC=HDMH, ORD=1, SPEC6=ANAWYP, ORD6=1. Changed: SPEC6 for Leucolia viridifrons (Green-fronted Hummingbird) to LEUVIR (from LEUVIF), ORD6 to 1 (from 2) to correct an oversight from 2020. Changed: SPEC6 for Chlorestes candida (White-bellied Emerald) to CHLCAD (from CHLCAN), ORD61 to 2 (from 1) to correct an oversight from 2020. Changed: NUMB for White-winged Parakeet (Brotogeris versicolurus) to 06130 (from 06133) to correct previous oversight. Changed: SPEC for Mayan Antrhush (Formicarius moniliger) to MAAN (from MYAN) to correct a previous error. Inserted at request of a user: Unidentified Pewee (Contopus sp.) (after Lesser Antillean Pewee); NUMB=11445, PNO=2, CAT=1, SPEC=UNPE, ORD=1, SPEC6=CONSPE, ORD6=1. Changed: SPEC for CAT=3 Hooded Crow to HCRO (from HOCR), ORD to 4 (from 1) in anticipation of conflicts in ORD=1 and ORD=2 codes resulting from the addition of CAT=2 species Hooded Crane (in 2022). ORD=3 code for Hooded Crow (HCRO) conflicts with that of CAT=2 species Hawaiian Crow. Inserted at request of a user: Pacific/Winter Wren (Troglodytes pacificus/hiemalis) (after Pacific Wren); NUMB=14115, PNO=2, CAT=1, SPEC=PWWR, ORD=1, SPEC6=TROPAH, ORD6=1 Changed: SPEC for Spot-breasted Wren (Pheugopedius maculipectus) to SOBW (from SBSW), ORD to N (from 4) due to conflict for ORD=4 code with those of Stripe- breasted and Speckle-breasted wrens. Inserted at request of a user: Eastern/Western Meadowlark (Sturna magna/neglecta) (after Eastern Meadowlark); NUMB=18015, PNO=2, CAT=1, SPEC=EWME, ORD=1, SPEC6=STUMAN, ORD6=1 Acknowledgments We thank Heather E. Brown, Peter Donaldson, Nathan Hentze, Anne-Marie Hudson, Danielle Kaschube, and Ron Taylor for corrections and feedback to the 2020 list, Carla Cicero and Terry Chesser for assistance with database cross-checking, and Bob Wilkerson for web assistance. .