NZ's flower expert Phil Garnock-Jones has an article in The Conversation on some of NZ's distinctive native plants that flower around Christmas time.
"Pōhutukawa flowers reflect strongly in both the red and ultraviolet wavelengths, but they absorb most of the blue and green wavelengths also found in sunlight. This is a pattern characteristic of bird-pollinated flowers, as is the fact that the flowers have no scent but produce a lot of nectar. Pōhutukawa flowers are also visited and pollinated by pekapeka, native short-tailed bats."