All pair bonds are heterosexual.
T he exact mechanisms involved in pair formation in parrots are obscure. In A. albifrons, pair formation appears to be a slow process with a gradual strengthening of the bond over time by means of allopreening and allofeeding . . . Only paired birds that copulated and bred were birds that exhibited allofeeding. One pair that was engaged in allopreenings did not attempt to breed in 1978 but began allofeeding in 1980 and bred that year. It thus seems that in the development of the pair-bonds, allopreening precedes allofeeding . . .