Partnership: Blue-faced Honeyeater

The fluffy flowers were waving in the light breeze when suddenly, a Blue-faced Honeyeater flew into the tree and began to probe the blossoms. The blooms had long, thin, white anthers that ended in pink. Each must have been an inch or more long. The nectar was at their base in what looked like a tight cluster, and a dozen or so flowers came off each of them, and there were multiple flower clumps up from the main branch. Just on this small section, the tree had plenty of places for this bird to find sweet food.

Here, we were witnessing another case of mutualism. The flower design is perfect for covering the bird’s face with pollen. In advertently, the bird then carries pollen to another tree in the honeyeater’s quest to find food, and, in the process, it pollinates that tree’s flowers. The bird eats, and the plant achieves the goal of mixing genes from different individuals. Australia is unique among the continents in that the majority of trees are pollinated through a partnership with birds, bats, and marsupials. In all other continents, most trees are pollinated either by insects or the wind. Sure, hummingbirds pollinate plants in the Western Hemisphere, but it is mostly shrubs and herbaceous vegetation.

Coevolution

The partnership began some 20 million years ago when Australia began to dry, creating new habitats and shrinking the tropical forests to the coast where those forests had previously covered most of the continent. Ecologists think the partnership supported the diversification of both the trees and honeyeaters. Four genera of trees, Eucalyptus, Melaleuca, Banksia, and Grevillia, evolved into more than a hundred species each, adapting to unique conditions across the continent. Honeyeaters have more than 70 species in Australia and another hundred in the Austral-New Guinea region.

The Blue-faced kept probing in and out of the flower cluster, and I continued to marvel at my luck in being able to see this. Here was the essence of Australia in many respects.