The following public domain (PD, CC 0) images were all downloaded from Pixabay:

toucan
https://pixabay.com/en/toucans-bird-556025/
https://pixabay.com/en/toucan-bird-bill-colorful-close-up-245174/

hummingbirds
https://pixabay.com/en/hummingbirds-birds-trochilidae-63107/
https://pixabay.com/en/hummingbird-flower-bird-nature-2747561/

hornbill
https://pixabay.com/en/animal-bird-hornbill-175033/
https://pixabay.com/en/wrinkled-hornbill-hornbill-colorful-1352493/
https://pixabay.com/en/rhino-horn-pachyderm-zoo-big-game-936288/

woodpecker and kingfisher
https://pixabay.com/en/woodpecker-bird-wildlife-nature-3184234/
https://pixabay.com/en/kingfisher-bird-alcedo-atthis-1338235/