U2 means umbrella cockatoos.
Well here's a whole list of abbreviations.
AKEET = American Parakeet
B&G = Blue and Gold Macaw
BC = Blue Crown Conure
BCC = Black Capped Conure
BE2 = Bare Eyed Cockatoo
BFA = Blue Front Amazon
BP2 = Black Palm Cockatoo
BSL = Blue Streak Lory
BWP = Bronze Winged Pionus
C2 = Citron Cockatoo
CAG = Congo African Grey
CBP = Coral Bill Pionus
CM = Catalina Macaw
DP = Dusky Pionus
DYH or DYHA = Double Yellow Head Amazon
E2 = Eleanora Cockatoo
ECKY = Eclectus
EKKIE = Eclectus
EKEET = English Parakeet
G2 = Goffin Cockatoo
GB = Great Bill
GC = Green Cheeked Conure
GCC = Gold Capped Conure
GCP = Grey Cheeked Parakeet
GE = Grand Eclectus
GS2 = Greater Sulphur Crested Cockatoo
GW or GWM = Green Wing Macaw
HH = Hawk Head Parrot
HM = Hahn’s Macaw
HMC = Half Moon Conure
HYM= Hyacinth Macaw
IR or IRN = Indian Ringneck
KEET = Parakeet
LP = Lineolated Parakeet
LS2 = Lesser Sulphur Crested Cockatoo
M2 = Moluccan Cockatoo
MBC = Maroon Belled Conure
MGM= Miligold Macaw
MM = Military Macaw
MM2 = Major Mitchell (Leadbeater) Cockatoo
MRHA - Mexican Red Head Amazon
MS2 = Medium Sulphur Crested Cockatoo
MP = Maximillian Pionus
OW or OWA = Orange Winged Amazon
PC = Painted Conure
Plet = Parrotlet
POW = Princess Parrot
QP = Quaker Parakeet
RB2 = Rose Breasted Cockatoo
RLA = Red Lored Amazon
RM = Ruby Macaw
RSE = Red Sided Eclectus
RV2 = Red Vented Cockatoo
SIE = Solomon Island Eclectus
SM = Scarlet Macaw
T2 = Triton Cockatoo
TAG = Timneh African Grey
TC= Timor Cockatoo
TIEL = Cockatiel
TOO = Cockatoo
U2 = Umbrella Cockatoo
VE = Vosmaeri's Eclectus
WCP = White Cap Pionus
WFA = White Fronted Amazon
WF = White Faced Cockatiel
YCM = Yellow Collared Macaw
YNA = Yellow Naped Amazon
