Hawaiian forests now have motion cameras, and they recently captured short-billed honeycreepers bypassing the openings of deep lobelioid blossoms.
A research team started tracking the behavior to see how long-billed pollinators are reshaping the flora of the area.
Avian extinctions are changing ecosystems. Species that survive have to change the way they feed. When evolutionary partners disappear, the island’s bird-plant relationships change.
How evolutionary partnerships alter island forest ecosystems
Hawaiian lobelioid flowers evolved long, curved corollas that match the shapes of native honeycreeper bills.
The plants get fertilized when a bird reaches in to get nectar and its head brushes against the pollen structures. When the bird moves on to the next flower, the pollen is transferred.
Habitat loss, disease, and invasive predators have seen several long-billed species disappear over the last century. There are deep lobelioid plants secured in native reserves, but the original pollinator birds have vanished.
One surviving species is the Hawaiʻi ʻamakihi. While they frequently access nectar from the base of certain blooms, their feeding behavior varies by plant species and includes normal front-opening visits that contribute to pollination.
They do not pass up the food, though; they access the nectar from the outside base of the bloom.
Their strategy involves poking through the tissue of the lower petal. But this way, they avoid contact with the pollen structures. There is a name for this behavior: nectar robbing.
While nectar-robbing visits bypass the flower’s reproductive structures, the plant can still be pollinated through subsequent visits or self-fertilization.
Ecological consequences for endangered flora must be measured
Researchers wanted to figure out how often this happens. They set up motion-activated cameras in native forest sites.
What the footage showed was short-billed birds legitimately making pollination visits to shorter flowers. But then they robbed the longer lobelioid blooms.
A pattern became clear across wide areas of the island. Local birds’ beaks are no longer long enough to match the depth of the flowers.
The nectar robbing-process is risky for rare plants. Energy is extracted, but the petals get damaged. Pollen does not get transferred. When the blossoms get damaged, fluid leaks out. The wounds mean the bloom may be weakened, and remaining pollinators are left with less food.
Researchers have concerns that the theft of nectar could drain the plant’s energy. Seed production could also be reduced. Experiments were needed to determine whether damaged lobelioid plants could still reproduce.
Researchers turned to 3D printing to look at botanical resilience
The researchers wanted to simulate the way nectar gets robbed. They 3D-printed a bird bill as a model.
The synthetic tool was used to puncture flower bases the way the short-billed birds do. Then researchers tracked nectar recovery seed production under controlled test conditions.
The trial showed that damaged flowers struggled to replenish their nectar stores compared to untouched blossoms, according to the University of Washington.
Yet despite the physical wounds and lower fluid levels, the plants showed clear resilience. Damaged lobelioids still produced fruit and viable seeds at rates comparable to unpunctured control flowers.
An effort to catalog Hawaiian bird-plant interactions
The study, published in Ecology and Evolution, demonstrates that while losing original pollinators disrupts historical relationships, Hawaiian lobelioids tolerate nectar theft better than expected.
When birds use this side-door mechanism for foraging, it becomes a middle ground in the altered ecosystems on Hawai’i. It is not an immediate failure of reproduction, but it may indicate what biologists can expect in the future.
There is a broader effort going on to catalog the interactions between birds and plants in forests in Hawai’i in relation to extinction. The way the flora on the island copes when it loses evolutionary partners must be understood to track how ecosystems adapt and relationships that were previously stable collapse.
The full study can be found here: Case, S. B., Drake, D. R., Epperly, K., Steinbronn, C., Kanakaokai, K., Hagemann, M. E., … & Rico‐Guevara, A. (2026). Mutualism and antagonism in a post‐extinction Hawaiian bird–lobelioid pollination system. Ecology and Evolution, 16(8), e74123.
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