觀無量壽佛經義疏 2.115

2.115

"‘Its light transforms into birds with the colors of a hundred jewels, harmonious and elegant in their singing, constantly praising mindfulness of the Buddha, mindfulness of the Dharma, and mindfulness of the Saṅgha.’" This corresponds to the white swans and peacocks in the Smaller Sūtra, and to the wild ducks, geese, and mandarin ducks mentioned below in the present sūtra; thus one knows that the precious birds are not of only one kind. Here it merely brings up the colors of their plumage to encompass all of them. They praise the Three Jewels in order to make [beings] take refuge in them. Fourth, concluding summary.