i've just gone through all the flags requesting the addition of bird hybrids, and added the following; all that's left to do is activate them:

Fulica × Gallinula: https://www.inaturalist.org/taxa/1204898-Fulica---Gallinula
Fulica americana × Gallinula galeata: https://www.inaturalist.org/taxa/1204899-Fulica-americana---Gallinula-galeata
Flag requesting addition: https://www.inaturalist.org/flags/522833

Anas crecca × Mareca penelope: https://www.inaturalist.org/taxa/1204900-Anas-crecca---Mareca-penelope
Flag requesting addition: https://www.inaturalist.org/flags/522398

Cyanoramphus novaezelandiae × auriceps: https://www.inaturalist.org/taxa/1204902-Cyanoramphus-novaezelandiae---auriceps
Flag requesting addition: https://www.inaturalist.org/flags/521884

Anas bahamensis × georgica: https://www.inaturalist.org/taxa/1204903-Anas-bahamensis---georgica
Flags requesting addition: https://www.inaturalist.org/flags/519714 and https://www.inaturalist.org/flags/523030

Anser × Cygnus: https://www.inaturalist.org/taxa/1201157-Anser---Cygnus
Anser anser × Cygnus olor: https://www.inaturalist.org/taxa/1201158-Anser-anser---Cygnus-olor
Flag requesting addition: https://www.inaturalist.org/flags/519150

Aix × Mareca: https://www.inaturalist.org/taxa/1204904-Aix---Mareca
Aix sponsa × Mareca americana: https://www.inaturalist.org/taxa/1204905-Aix-sponsa---Mareca-americana
Flags requesting addition: https://www.inaturalist.org/flags/518572 and https://www.inaturalist.org/flags/518593

Anser albifrons × Branta leucopsis: https://www.inaturalist.org/taxa/1204907-Anser-albifrons---Branta-leucopsis
Anser albifrons × Branta ruficollis: https://www.inaturalist.org/taxa/1204908-Anser-albifrons---Branta-ruficollis
Anser anser × Branta leucopsis: https://www.inaturalist.org/taxa/1204909-Anser-anser---Branta-leucopsis
Anser brachyrhynchus × Branta canadensis: https://www.inaturalist.org/taxa/1204910-Anser-brachyrhynchus---Branta-canadensis
Anser brachyrhynchus × Branta leucopsis: https://www.inaturalist.org/taxa/1204911-Anser-brachyrhynchus---Branta-leucopsis
Anser caerulescens × Branta bernicla: https://www.inaturalist.org/taxa/1204912-Anser-caerulescens---Branta-bernicla
Anser canagicus × Branta hutchinsii: https://www.inaturalist.org/taxa/1204913-Anser-canagicus---Branta-hutchinsii
Anser indicus × Branta canadensis: https://www.inaturalist.org/taxa/1204914-Anser-indicus---Branta-canadensis
Anser rossii × Branta canadensis: https://www.inaturalist.org/taxa/1204915-Anser-rossii---Branta-canadensis
Anser rossii × Branta hutchinsii: https://www.inaturalist.org/taxa/1204916-Anser-rossii---Branta-hutchinsii
Flags requesting addition: https://www.inaturalist.org/flags/518554 and https://www.inaturalist.org/flags/461134

Archilochus × Calypte: https://www.inaturalist.org/taxa/1204917-Archilochus---Calypte
Flag requesting addition: https://www.inaturalist.org/flags/518470

Anas × Tadorna: https://www.inaturalist.org/taxa/1204918-Anas---Tadorna
Anas platyrhynchos × Tadorna ferruginea: https://www.inaturalist.org/taxa/1204919-Anas-platyrhynchos---Tadorna-ferruginea
Flag requesting addition: https://www.inaturalist.org/flags/517189

Sialia sialis × currucoides: https://www.inaturalist.org/taxa/1204921-Sialia-sialis---currucoides
Sialia sialis × mexicana: https://www.inaturalist.org/taxa/1204922-Sialia-sialis---mexicana
Flag requesting addition: https://www.inaturalist.org/flags/516014

Vanellus armatus × albiceps: https://www.inaturalist.org/taxa/1204923-Vanellus-armatus---albiceps
Flag requesting addition: https://www.inaturalist.org/flags/512258

Tadorna ferruginea × tadorna: https://www.inaturalist.org/taxa/1204924-Tadorna-ferruginea---tadorna
Flag requesting addition: https://www.inaturalist.org/flags/507627

Zonotrichia leucophrys leucophrys × gambelii: https://www.inaturalist.org/taxa/1204925-Zonotrichia-leucophrys-leucophrys---gambelii
Flag requesting addition: https://www.inaturalist.org/flags/506726

Tyrannus couchii × verticalis: https://www.inaturalist.org/taxa/1204926-Tyrannus-couchii---verticalis
Flag requesting addition: https://www.inaturalist.org/flags/505322

Leucosticte tephrocotis littoralis × tephrocotis: https://www.inaturalist.org/taxa/1204927-Leucosticte-tephrocotis-littoralis---tephrocotis
Flag requesting addition: https://www.inaturalist.org/flags/523000

Ara ararauna × chloropterus: https://www.inaturalist.org/taxa/1204928-Ara-ararauna---chloropterus
Flag requesting addition: https://www.inaturalist.org/flags/504727

Anas platyrhynchos × chlorotis: https://www.inaturalist.org/taxa/1204930-Anas-platyrhynchos---chlorotis
Flag requesting addition: https://www.inaturalist.org/flags/503411

Phylidonyris novaehollandiae × niger: https://www.inaturalist.org/taxa/1204931-Phylidonyris-novaehollandiae---niger
Flag requesting addition: https://www.inaturalist.org/flags/502698

Zonotrichia leucophrys × albicollis: https://www.inaturalist.org/taxa/1204935-Zonotrichia-leucophrys---albicollis
Zonotrichia leucophrys × querula: https://www.inaturalist.org/taxa/1204936-Zonotrichia-leucophrys---querula
Zonotrichia atricapilla × albicollis: https://www.inaturalist.org/taxa/1204937-Zonotrichia-atricapilla---albicollis
Spizelloides × Zonotrichia: https://www.inaturalist.org/taxa/1204938-Spizelloides---Zonotrichia
Spizelloides arborea × Zonotrichia querula: https://www.inaturalist.org/taxa/1204942-Spizelloides-arborea---Zonotrichia-querula
Flags requesting addition: https://www.inaturalist.org/flags/501039 and https://www.inaturalist.org/flags/467476

Anas platyrhynchos × Tadorna variegata: https://www.inaturalist.org/taxa/1204952-Anas-platyrhynchos---Tadorna-variegata
Flag requesting addition: https://www.inaturalist.org/flags/487171

Pipilo maculatus × erythrophthalmus: https://www.inaturalist.org/taxa/1204953-Pipilo-maculatus---erythrophthalmus
Flag requesting addition: https://www.inaturalist.org/flags/487066

Archilochus × Selasphorus: https://www.inaturalist.org/taxa/1204955-Archilochus---Selasphorus
Archilochus alexandri × Selasphorus rufus: https://www.inaturalist.org/taxa/1204956-Archilochus-alexandri---Selasphorus-rufus
Flag requesting addition: https://www.inaturalist.org/flags/485443

Selasphorus flammula × scintilla: https://www.inaturalist.org/taxa/1204965-Selasphorus-flammula---scintilla
Flag requesting addition: https://www.inaturalist.org/flags/478579

Archilochus colubris × alexandri: https://www.inaturalist.org/taxa/1204969-Archilochus-colubris---alexandri
Flag requesting addition: https://www.inaturalist.org/flags/478020

Calypte anna × Selasphorus rufus: https://www.inaturalist.org/taxa/1204971-Calypte-anna---Selasphorus-rufus
Calypte anna × Selasphorus sasin: https://www.inaturalist.org/taxa/1204972-Calypte-anna---Selasphorus-sasin
Flag requesting addition: https://www.inaturalist.org/flags/478015

Somateria mollissima × Mergus merganser: https://www.inaturalist.org/taxa/1204974-Somateria-mollissima---Mergus-merganser
Flag requesting addition: https://www.inaturalist.org/flags/478009

Amazona viridigenalis × oratrix: https://www.inaturalist.org/taxa/1204977-Amazona-viridigenalis---oratrix
Flag requesting addition: https://www.inaturalist.org/flags/477743

Sericulus × Ptilonorhynchus: https://www.inaturalist.org/taxa/1204978-Sericulus---Ptilonorhynchus
Sericulus chrysocephalus × Ptilonorhynchus violaceus: https://www.inaturalist.org/taxa/1204980-Sericulus-chrysocephalus---Ptilonorhynchus-violaceus
Flag requesting addition: https://www.inaturalist.org/flags/475022

Petrochelidon pyrrhonota × fulva: https://www.inaturalist.org/taxa/1204981-Petrochelidon-pyrrhonota---fulva
Flag requesting addition: https://www.inaturalist.org/flags/471664

Calothorax × Calypte: https://www.inaturalist.org/taxa/1204982-Calothorax---Calypte
Calothorax lucifer × Calypte costae: https://www.inaturalist.org/taxa/1204984-Calothorax-lucifer---Calypte-costae
Flags requesting addition: https://www.inaturalist.org/flags/471630 and https://www.inaturalist.org/flags/471369

Oenanthe hispanica × pleschanka: https://www.inaturalist.org/taxa/1204986-Oenanthe-hispanica---pleschanka
Flag requesting addition: https://www.inaturalist.org/flags/466593

Colaptes auratus × chrysoides: https://www.inaturalist.org/taxa/1204987-Colaptes-auratus---chrysoides
Flag requesting addition: https://www.inaturalist.org/flags/463122

Selasphorus rufus × sasin: https://www.inaturalist.org/taxa/1204989-Selasphorus-rufus---sasin
Flag requesting addition: https://www.inaturalist.org/flags/430455

Selasphorus rufus × calliope: https://www.inaturalist.org/taxa/1204991-Selasphorus-rufus---calliope
Flag requesting addition: https://www.inaturalist.org/flags/429974

Selasphorus platycercus × calliope: https://www.inaturalist.org/taxa/1204992-Selasphorus-platycercus---calliope
Flag requesting addition: https://www.inaturalist.org/flags/429973

Ara ararauna × macao: https://www.inaturalist.org/taxa/1204929-Ara-ararauna---macao
Flag requesting addition: https://www.inaturalist.org/flags/331015

Carduelis × Chloris: https://www.inaturalist.org/taxa/1204993-Carduelis---Chloris
Carduelis carduelis × Chloris chloris: https://www.inaturalist.org/taxa/1204994-Carduelis-carduelis---Chloris-chloris
Flag requesting addition: https://www.inaturalist.org/flags/418867

Agapornis roseicollis × fischeri: https://www.inaturalist.org/taxa/1204995-Agapornis-roseicollis---fischeri
Agapornis roseicollis × personatus: https://www.inaturalist.org/taxa/1204996-Agapornis-roseicollis---personatus
Flags requesting addition: https://www.inaturalist.org/flags/461128 and https://www.inaturalist.org/flags/408944

Aglaiocercus × Metallura: https://www.inaturalist.org/taxa/1204997-Aglaiocercus---Metallura
Flag requesting addition: https://www.inaturalist.org/flags/429971

Carduelis × Serinus: https://www.inaturalist.org/taxa/1204998-Carduelis---Serinus
Flag requesting addition: https://www.inaturalist.org/flags/397647

Anas rubripes × Mareca americana: https://www.inaturalist.org/taxa/1204999-Anas-rubripes---Mareca-americana
Flag requesting addition: https://www.inaturalist.org/flags/340474

Archilochus alexandri × Calypte anna: https://www.inaturalist.org/taxa/1205000-Archilochus-alexandri---Calypte-anna
Flag requesting addition: https://www.inaturalist.org/flags/301373

Rallus elegans × crepitans: https://www.inaturalist.org/taxa/1205083-Rallus-elegans---crepitans
Flag requesting addition: https://www.inaturalist.org/flags/523051

The observation field Holding bin (birds) includes all of the forms and many of the slashes and spuhs from the eBird taxonomy (which can be downloaded here). The following eBird slashes and spuhs directly correspond to a taxon already in iNat (genus, family, order, etc.), so have been removed from the list of allowed values for the observation field – instead, observations should simply be identified as the relevant taxon on iNaturalist:
accentor sp. = Prunella
Accipiter sp. = Accipiter
Acridotheres sp. = Acridotheres
Acrocephalus sp. = Acrocephalus
Aethopyga sp. = Aethopyga
african barbet sp. = Lybiidae
african cuckooshrike sp. = Campephaga
African seedeater sp. = Crithagra
african trogon sp. = Apaloderma
albatross sp. = Diomedeidae
alcid sp. = Alcidae
Alcippe sp. = Alcippe
Amazilia sp. = Amazilia
Amazona sp. = Amazona
Ammodramus sp. = Ammodramus
Ammomanes sp. = Ammomanes
Anabacerthia sp. = Anabacerthia
Anairetes sp. = Anairetes
Anna's/Costa's Hummingbird = Calypte
Anser sp. = Anser
Antrostomus sp. = Antrostomus
ant-tanager sp. = Habia
antthrush sp. = Formicariidae
antvireo sp. = Dysithamnus
Apalis sp. = Apalis
Aphelocoma sp. = Aphelocoma
Aplonis sp. = Aplonis
Apus sp. = Apus
Aquila sp. = Aquila
aracari sp. = Pteroglossus
Arborophila sp. = Arborophila
Ardea sp. = Ardea
Arizelocichla sp. = Arizelocichla
asian barbet sp. = Megalaimidae
asian broadbill sp. = Eurylaimidae
asian trogon sp. = Harpactes
Asio sp. = Asio
Atlapetes sp. = Atlapetes
attila sp. = Attila
Aulacorhynchus sp. = Aulacorhynchus
Austral/Andean Negrito = Lessonia
Austral/Slender-billed Parakeet = Enicognathus
Automolus sp. = Automolus
Aythya sp. = Aythya
Basileuterus sp. = Basileuterus
Batis sp. = Batis
Batrachostomus sp. = Batrachostomus
becard sp. = Pachyramphus
bee-eater sp. = Merops
bird sp. = Aves
Black-bellied Plover/golden-plover sp. = Pluvialis
blackbird sp. = Icteridae
Black-casqued/Yellow-casqued Hornbill = Ceratogymna
black-cockatoo sp. = Calyptorhynchus
Black-crested/Gray-crested Finch = Lophospingus
Black-legged/Red-legged Kittiwake = Rissa
Black-tailed/Green-tailed Trainbearer = Lesbia
black-tyrant sp. = Knipolegus
blue cotinga sp. = Cotinga
blue flycatcher sp. = Cyornis
Blue-and-white/Zappey's Flycatcher = Cyanoptila
bluebird sp. = Sialia
boobook sp. = Ninox
booby sp. = Sula
boubou sp. = Laniarius
Brachypteryx sp. = Brachypteryx
Bradornis sp. = Bradornis
Bradypterus sp. = Bradypterus
Branta sp. = Branta
bristlebill sp. = Bleda
Brotogeris sp. = Brotogeris
Brown/Gray Trembler = Cinclocerthia
brown-dove sp. = Phapitreron
Bubo sp. = Bubo
Bucconidae sp. = Bucconidae
Burhinus sp. = Burhinus
bush warbler sp. = Horornis
bustard sp. = Otididae
Buteo sp. = Buteo
Buteogallus sp. = Buteogallus
buttonquail sp. = Turnix
cacique sp. = Cacicus
Cacomantis sp. = Cacomantis
Calandrella sp. = Calandrella
Calidris sp. = Calidris
Camaroptera sp. = Camaroptera
Campephilus sp. = Campephilus
canastero sp. = Asthenes
Cantorchilus sp. = Cantorchilus
Capito sp. = Capito
Caprimulgus sp. = Caprimulgus
Catamenia sp. = Catamenia
Cathartes sp. = Cathartes
Catharus sp. = Catharus
Celeus sp. = Celeus
Cercococcyx sp. = Cercococcyx
Cercomacroides sp. = Cercomacroides
Cettia sp. = Cettia
chachalaca sp. = Ortalis
Chaetocercus sp. = Chaetocercus
Chaetura sp. = Chaetura
Chamaeza sp. = Chamaeza
Charmosyna sp. = Charmosyna
chat-tyrant sp. = Ochthoeca
chickadee sp. = Poecile
Chlidonias sp. = Chlidonias
Chloephaga sp. = Chloephaga
Chloroceryle sp. = Chloroceryle
Chlorospingus sp. = Chlorospingus
Chlorostilbon sp. = Chlorostilbon
Chlorothraupis sp. = Chlorothraupis
Chrysococcyx sp. = Chrysococcyx
Ciccaba sp. = Ciccaba
Ciconia sp. = Ciconia
Cinclodes sp. = Cinclodes
Cinnycerthia sp. = Cinnycerthia
Cinnyris sp. = Cinnyris
cisticola sp. = Cisticola
Coccyzus sp. = Coccyzus
Colluricincla sp. = Colluricincla
Columba sp. = Columba
Common/Somali Ostrich = Struthio
Common/Spotted Sandpiper = Actitis
Common/Thick-billed Murre = Uria
conebill sp. = Conirostrum
coot sp. = Fulica
Coracina sp. = Coracina
cordonbleu sp. = Uraeginthus
corella/cockatoo sp. = Cacatua
cormorant sp. = Phalacrocoracidae
Coua sp. = Coua
coucal sp. = Centropus
Cracidae sp. = Cracidae
crane sp. = Gruidae
Cranioleuca sp. = Cranioleuca
Crimson/Fiery Topaz = Topaza
Criniger sp. = Criniger
crombec sp. = Sylvietta
crossbill sp. = Loxia
crow/raven sp. = Corvus
Crypturellus sp. = Crypturellus
cuckoo sp. (Cuculidae sp.) = Cuculidae
cuckooshrike sp. = Campephagidae
Cuculus sp. = Cuculus
cupwing sp. = Pnoepyga
curlew sp. = Numenius
currawong sp. = Strepera
Cyanocorax sp. = Cyanocorax
Cyanoderma sp. = Cyanoderma
Cyanoramphus sp. = Cyanoramphus
Cypseloides sp. = Cypseloides
dabbling duck sp. = Anas (or Anatini)
Dacnis sp. = Dacnis
dark swiftlet sp. = Aerodramus
Dark-eared/White-eared Myza = Myza
Daurian/Chestnut-cheeked Starling = Agropsar
Dendrocincla sp. = Dendrocincla
Dendrocolaptes sp. = Dendrocolaptes
Dendrocopos sp. = Dendrocopos
Dicaeum sp. = Dicaeum
diving-petrel sp. = Pelecanoides
doradito sp. = Pseudocolopteryx
drongo sp. = Dicrurus
Drymophila sp. = Drymophila
Dryocopus sp. = Dryocopus
Dusky/Sooty Grouse = Dendragapus
Edolisoma sp. = Edolisoma
eider sp. = Somateria
elaenia sp. (genus Elaenia) = Elaenia
elaenia sp. (genus Myiopagis) = Myiopagis
Emberiza sp. = Emberiza
Empidonax sp. = Empidonax
Epinecrophylla sp. = Epinecrophylla
Eremomela sp. = Eremomela
Erythropitta sp. = Erythropitta
estrildid finch sp. = Estrildidae
Euchrepomis sp. = Euchrepomis
euphonia sp. = Euphonia
Euplectes sp. = Euplectes
Eurillas sp. = Eurillas
European/Spotless Starling = Sturnus
fairywren sp. = Malurus
falcon sp. = Falco
fantail sp. = Rhipidura
Ficedula sp. = Ficedula
finch sp. = Fringillidae
firefinch sp. = Lagonosticta
flameback sp. = Dinopium
flamingo sp. = Phoenicopteridae
flatbill sp. = Rhynchocyclus
flowerpecker sp. = Dicaeidae
flowerpiercer sp. = Diglossa
flufftail sp. = Sarothrura
flycatcher sp. (Tyrannidae sp.) = Tyrannidae
forest-falcon sp. = Micrastur
forktail sp. = Enicurus
Formicarius sp. = Formicarius
Forpus sp. = Forpus
friarbird sp. = Philemon
frigatebird sp. = Fregata
frogmouth sp. = Podargidae
fruit-dove sp. = Ptilinopus
Fulvetta sp. = Fulvetta
Furnariid sp. = Furnariidae
Galbula sp. = Galbula
Garrulax sp. = Garrulax
Gavicalis sp. = Gavicalis
Geokichla sp. = Geokichla
Geospiza sp. = Geospiza
Geranoaetus sp. = Geranoaetus
gerygone sp. = Gerygone
Glaucidium sp. = Glaucidium
gnatcatcher sp. = Polioptila
godwit sp. = Limosa
grackle sp. = Quiscalus
Grallaria sp. = Grallaria
Grayish/Pale Baywing = Agelaioides
Greater/Gunnison Sage-Grouse = Centrocercus
grebe sp. = Podicipedidae
Green/Striated Heron = Butorides
green-magpie sp. = Cissa
ground-dove/Inca Dove sp. = Columbina
ground-tyrant sp. = Muscisaxicola
gull sp. = Larinae
gull/tern sp. = Laridae
Gyps sp. = Gyps
Haemorhous sp. = Haemorhous
Haliaeetus sp. = Haliaeetus
hanging-parrot sp. = Loriculus
harrier sp. = Circus
hawk-cuckoo sp. = Hierococcyx
helmetcrest sp. = Oxypogon
Hemitriccus sp. = Hemitriccus
hermit sp. = Phaethornis
heron sp. = Ardeidae
Herpsilochmus sp. = Herpsilochmus
Hippolais sp. = Hippolais
Hirundapus sp. = Hirundapus
honeyguide sp. = Indicatoridae
hornbill sp. = Bucerotidae
Horned/Temminck’s Lark = Eremophila
hornero sp. = Furnarius
house-martin sp. = Delichon
hummingbird sp. = Trochilidae
Hydropsalis sp. = Hydropsalis
Hydrornis sp. = Hydrornis
Ianthocincla sp. = Ianthocincla
Iduna sp. = Iduna
Illadopsis sp. = Illadopsis
imperial-pigeon sp. = Ducula
inca-finch sp. = Incaspiza
Iole sp. = Iole
Ixothraupis sp. (speckled tanager sp.) = Ixothraupis
jacamar sp. = Galbulidae
jacana sp. = Jacanidae
jaeger/skua sp. = Stercorarius
jery sp. = Neomixis
jewel-babbler sp. = Ptilorrhoa
Keel-billed/Broad-billed Motmot = Electron
kingfisher sp. = Alcedinidae
kinglet sp. = Regulus
Lalage sp. = Lalage
Lamprotornis sp. = Lamprotornis
lapwing sp. = Vanellus
large albatross sp. = Diomedea
large honeyguide sp. = Indicator
large macaw sp. = Ara
large toucan sp. = Ramphastos
lark sp. = Alaudidae
Larus sp. = Larus
leafbird sp. = Chloropsis
leaftosser sp. = Sclerurus
Lepidocolaptes sp. = Lepidocolaptes
Lepidothrix sp. = Lepidothrix
Leptotila sp. = Leptotila
Lesser/Greater Roadrunner = Geococcyx
Locustella sp. = Locustella
Lonchura sp. = Lonchura
longbill sp. = Macrosphenus
longclaw sp. = Macronyx
loon sp. = Gavia
Lophoceros sp. = Lophoceros
Lophotriccus sp. = Lophotriccus
Louisiana/Northern Waterthrush = Parkesia
lovebird sp. = Agapornis
Lucifer/Beautiful Hummingbird = Calothorax
Macropygia sp. = Macropygia
Malacopteron sp. = Malacopteron
malimbe sp. = Malimbus
manakin sp. = Pipridae
mango sp. = Anthracothorax
martin sp. (Progne sp.) = Progne
Megalurus sp. = Megalurus
Melanerpes sp. = Melanerpes
Melanocharis berrypecker sp. = Melanocharis
melidectes sp. = Melidectes
Meliphaga sp. = Meliphaga
Meliphagidae sp. = Meliphagidae
Melipotes sp. = Melipotes
Melithreptus sp. = Melithreptus
metaltail sp. = Metallura
Microeca sp. = Microeca
Mimidae sp. = Mimidae
miner sp. (Geositta sp.) = Geositta
miner sp. (Manorina sp.) = Manorina
minivet sp. = Pericrocotus
Mionectes sp. = Mionectes
Mirafra sp. = Mirafra
Mississippi/Plumbeous Kite = Ictinia
Monarcha sp. = Monarcha
Monasa sp. = Monasa
motmot sp. = Momotidae
mousebird sp. = Coliidae
mouse-warbler sp. = Crateroscelis
Muscicapa sp. = Muscicapa
Muscicapid sp. = Muscicapidae
Mycerobas sp. = Mycerobas
Myiagra sp. = Myiagra
Myiarchus sp. = Myiarchus
Myiobius sp. = Myiobius
Myioborus sp. = Myioborus
Myiophobus sp. = Myiophobus
Myiotheretes sp. = Myiotheretes
Myiothlypis sp. = Myiothlypis
myna/starling sp. = Sturnidae
Myrmelastes sp. = Myrmelastes
Myrmotherula sp. = Myrmotherula
myzomela sp. = Myzomela
Neophema sp. = Neophema
new world barbet sp. = Capitonidae
new world oriole sp. = Icterus
new world piculet sp. = Picumnus
new world quail sp. = Odontophoridae
new world trogon sp. = Trogon
new world vulture sp. = Cathartidae
nighthawk sp. = Chordeiles
nightjar sp. = Caprimulgidae
niltava sp. = Niltava
Nisaetus sp. = Nisaetus
Northern/Southern Giant-Petrel = Macronectes
Northern/Southern Rough-winged Swallow = Stelgidopteryx
Northern/Wattled Jacana = Jacana
Nothoprocta sp. = Nothoprocta
nunlet sp. = Nonnula
nuthatch sp. = Sitta
Oceanites sp. = Oceanites
Oceanodroma sp. = Oceanodroma
old world oriole sp. = Oriolus
Oreothlypis sp. = Oreothlypis
Oreotrochilus sp. = Oreotrochilus
oropendola sp. = Psarocolius
owl sp. = Strigiformes
owlet-nightjar sp. = Aegotheles
oystercatcher sp. = Haematopus
Pachycephala sp. = Pachycephala
paradise-flycatcher sp. = Terpsiphone
pardalote sp. = Pardalotus
Parid sp. = Paridae
parrotbill sp. = Paradoxornithidae
Parus sp. = Parus
Passer sp. = Passer
Passerina sp. = Passerina
passerine sp. = Passeriformes
Patagioenas sp. = Patagioenas
pelican sp. = Pelecanus
Pellorneidae sp. = Pellorneidae
Penelope sp. = Penelope
penguin sp. = Spheniscidae
Petrochelidon sp. = Petrochelidon
Petroica sp. = Petroica
Peucaea sp. = Peucaea
pewee sp. (Contopus sp.) = Contopus
phalarope sp. = Phalaropus
Pheucticus sp. = Pheucticus
Pheugopedius sp. = Pheugopedius
Philydor sp. = Philydor
phoebe sp. = Sayornis
Phyllastrephus sp. = Phyllastrephus
Phyllomyias sp. = Phyllomyias
Phylloscartes sp. = Phylloscartes
Phylloscopus sp. = Phylloscopus
Pica sp. = Pica
Picoides sp. = Picoides
Piculus sp. = Piculus
Picus sp. = Picus
pigeon/dove sp. = Columbidae
Pionus sp. = Pionus
pipit sp. = Anthus
Pipreola sp. = Pipreola
Pitta sp. (genus Erythropitta/Hydrornis/Pitta) = Pittidae
Pitta sp. (genus Pitta) = Pitta
Ploceus sp. = Ploceus
plover sp. = Charadriidae
Podiceps sp. = Podiceps
Poecilotriccus sp. = Poecilotriccus
Poicephalus sp. = Poicephalus
Pomatorhinus sp. = Pomatorhinus
pond-heron sp. = Ardeola
potoo sp. = Nyctibius
pratincole sp. = Glareola
prinia sp. = Prinia
prion sp. = Pachyptila
Prionochilus sp. = Prionochilus
Procellaria sp. = Procellaria
Procellariid sp. = Procellariidae
pseudo-babbler sp. = Pomatostomus
Psilopogon sp. = Psilopogon
Psittacara sp. = Psittacara
Psittacula sp. = Psittacula
ptarmigan sp. = Lagopus
Pterodroma sp. = Pterodroma
puffback sp. = Dryoscopus
puffin sp. = Fratercula
Pulsatrix sp. = Pulsatrix
Pycnonotidae sp. = Pycnonotidae
Pycnonotus sp. = Pycnonotus
pygmy-parrot sp. = Micropsitta
Pyrilia sp. = Pyrilia
Pyrrhura sp. = Pyrrhura
pytilia sp. = Pytilia
quelea sp. = Quelea
racquet-tail sp. = Prioniturus
Rallina sp. = Rallina
Rallus sp. = Rallus
Ramphocelus sp. = Ramphocelus
Ramphotrigon sp. = Ramphotrigon
Red/Black Kite = Milvus
Red-billed/Yellow-billed Chough = Pyrrhocorax
Red-billed/Yellow-billed Oxpecker = Buphagus
redpoll sp. = Acanthis
redstart sp. = Phoenicurus
Riparia sp. = Riparia
robin-chat sp. = Cossypha
rock-thrush sp. = Monticola
roller sp. = Coracias
rosefinch sp. = Carpodacus
rosy-finch sp. = Leucosticte
Ruby-throated/Black-chinned Hummingbird = Archilochus
Rufous-browed/Black-billed Peppershrike = Cyclarhis
Rufous-winged/Maroon-breasted Philentoma = Philentoma
Rusty/Brewer’s Blackbird = Euphagus
Sagebrush/Bell’s Sparrow (Sage Sparrow) = Artemisiospiza
saltator sp. = Saltator
sandgrouse sp. = Pterocles
sapsucker sp. = Sphyrapicus
sawwing sp. = Psalidoprocne
Saxicola sp. = Saxicola
Scarce/Schouteden’s Swift = Schoutedenapus
Schiffornis sp. = Schiffornis
Schoeniparus sp. = Schoeniparus
Scolopacidae sp. = Scolopacidae
scops-owl sp. = Otus
scoter sp. = Melanitta
screech-owl sp. = Megascops
scrub-flycatcher sp. = Sublegatus
scrub-robin sp. = Cercotrichas
scrubwren sp. = Sericornis
Scytalopus sp. = Scytalopus
scythebill sp. = Campylorhamphus
Seicercus sp. = Seicercus
Selasphorus sp. = Selasphorus
Serinus sp. = Serinus
Serpophaga sp. = Serpophaga
Setophaga sp. = Setophaga
shorebird sp. = Charadriiformes
shrike sp. = Lanius
shrike-babbler sp. = Pteruthius
shrike-tyrant sp. = Agriornis
sierra-finch sp. = Phrygilus
sirystes sp. = Sirystes
small albatross sp. = Thalassarche
small bittern sp. = Ixobrychus
small honeyguide sp. = Prodotiscus
small plover sp. = Charadrius
Smithornis sp. = Smithornis
snake-eagle sp. = Circaetus
snipe sp. = Gallinago
Snow/McKay’s Bunting = Plectrophenax
softtail sp. = Thripophaga
spadebill sp. = Platyrinchus
spiderhunter sp. = Arachnothera
Spinus sp. = Spinus
Spizaetus sp. = Spizaetus
Spizella sp. = Spizella
spoonbill sp. = Platalea
Sporophila sp. = Sporophila
Squirrel/Black-bellied Cuckoo = Piaya
Stachyris sp. = Stachyris
steamer-duck sp. = Tachyeres
Sterna sp. = Sterna
stilt/avocet sp. = Recurvirostridae
stork sp. = Ciconiidae
storm-petrel sp. = Hydrobatidae
Straight-billed/Zimmer’s Woodcreeper = Dendroplex
Streptopelia sp. = Streptopelia
Streptoprocne sp. = Streptoprocne
Suiriri/Chapada Flycatcher = Suiriri
sulid sp. = Sulidae
Sunbird/Yellow-bellied Asity = Neodrepanis
swallow sp. = Hirundinidae
swan sp. = Cygnus
swift sp. = Apodidae
Sylvia sp. = Sylvia
Synallaxis sp. = Synallaxis
Syndactyla sp. = Syndactyla
Tachycineta sp. = Tachycineta
Tachyphonus sp. = Tachyphonus
tailorbird sp. = Orthotomus
Talegalla sp. = Talegalla
tanager sp. (Piranga sp.) = Piranga
Tangara sp. = Tangara
tapaculo sp. = Rhinocryptidae
Tarsiger sp. = Tarsiger
Tauraco sp. = Tauraco
Tchagra sp. = Tchagra
tern sp. = Sterninae
tesia sp. = Tesia
Thamnophilus sp. = Thamnophilus
Thlypopsis sp. = Thlypopsis
thornbill sp. = Acanthiza
thornbird sp. = Phacellodomus
Thraupis sp. = Thraupis
thrush sp. = Turdidae
Thrush-like/Tepui Antpitta = Myrmothera
tiger-heron sp. = Tigrisoma
tiger-parrot sp. = Psittacella
tinamou sp. = Tinamidae
Tinamus sp. = Tinamus
tinkerbird sp. = Pogoniulus
tit-spinetail sp. = Leptasthenura
Tityra sp. = Tityra
Tockus sp. = Tockus
Todiramphus sp. = Todiramphus
Todirostrum sp. = Todirostrum
Tolmomyias sp. = Tolmomyias
Touit sp. = Touit
Toxostoma sp. = Toxostoma
treecreeper sp. = Certhia
treeswift sp. = Hemiprocne
Treron sp. = Treron
Tringa sp. = Tringa
Trochalopteron sp. = Trochalopteron
tropicbird sp. = Phaethon
trumpeter sp. = Psophia
turaco sp. = Musophagidae
Turdoides sp. = Turdoides
Turdus sp. = Turdus
Turtur sp. = Turtur
Tyrannus sp. = Tyrannus
Upucerthia sp. = Upucerthia
Vangidae sp. = Vangidae
Veniliornis sp. = Veniliornis
Vidua sp. = Vidua
violetear sp. = Colibri
vireo sp. = Vireo
wagtail sp. = Motacilla
warbler sp. (Parulidae sp.) = Parulidae
waterfowl sp. = Anatidae
wattlebird sp. = Anthochaera
wattle-eye sp. = Platysteira
waxbill sp. = Estrilda
Western/Clark’s Grebe = Aechmophorus
wheatear sp. = Oenanthe
whistling-duck sp. = Dendrocygna
whistling-thrush sp. = Myophonus
white-bellied swiftlet sp. = Collocalia
white-eye sp. = Zosteropidae
woodcreeper sp. = Dendrocolaptinae
woodhoopoe sp. = Phoeniculus
woodhoopoe/scimitarbill sp. = Phoeniculidae
woodpecker sp. = Picidae
wood-quail sp. = Odontophorus
wood-rail sp. = Aramides
woodswallow sp. = Artamus
wood-wren sp. = Henicorhina
wren sp. = Troglodytidae
xenops sp. = Xenops
Xiphorhynchus sp. = Xiphorhynchus
Yellow-bellied/Slaty-chinned Longbill = Toxorhamphus
Yellow-billed/Mountain Kingfisher = Syma
Yellow-billed/Orange-billed Lorikeet = Neopsittacus
yellow-finch sp. = Sicalis
yuhina sp. = Yuhina
Zapornia sp. = Zapornia
Zimmerius sp. = Zimmerius
Zonotrichia sp. = Zonotrichia
Zoothera sp. = Zoothera
Zosterops sp. = Zosterops

There are four special cases that I've left as allowed values: two slashes which correspond to genera with two described species but also an undescribed form (Chestnut-tailed/Zimmer's Antbird and Yellow-chinned/Red-and-white Spinetail); Black-crowned/Rufous Night-Heron (there are several extinct species in the genus Nycticorax that aren't currently on the Clements checklist but could be added in the future – not that anyone will be reporting any of those to iNaturalist); and babbler sp. (which currently has the scientific name Timaliidae sp. in the eBird taxonomy, but the common name makes it unclear if the scientific name is an error and if it's meant for Pellorneidae, Leiothrichidae, etc. as well). (If anyone thinks of anything else in the above list that could be re-added as an allowed value, let me know.)
In addition, a few of the two-species genera that correspond to a slash may not contain two species forever (e.g. Eremophila, Milvus), and the scope of some of the spuhs could potentially change – just something to keep in mind for whoever’s editing the allowed values for this field after the next Clements update (and the next, and the next… I’ll volunteer to do it, but just in case I can’t for whatever reason or I haven’t updated them in a reasonable amount of time or something like that)