Almost no one likes an invasive species. After all, they usually take over, crowding out indigenous occupants, sometimes even leading to extinctions. This island of Kauai has more than its share of invasive species, but two seem to stand out — parakeets and figs.

Rose Ringed Parakeets
Rose ringed parakeets, originally native to Southern Asia and Central Africa, are popular pets all over the world. Occasionally, they escape their captivity. Then, under the right conditions, these smart, and adaptive birds naturalize.

It’s thought that parakeets were somehow released in Kauai in the 1960s. Experts agree that the parakeets now number at least 11,000 birds.

Obviously, the rose ringed parakeets on Kauai are delighted with their new home. Food is plentiful, and at night a they have a multitude of safe places to roost, with no natural predators to worry them.

Island farmers, though, are not happy. Many Kauai crops such as citrus, papaya, mango, lychee and corn have become bird food, forcing growers to invest in anti-parakeet measures.

The birds’ droppings are also playing havoc in hotel parking lots. The droppings are full of seeds, which not only attracts rats, but can ruin a car’s paint unless removed promptly.

So far, researchers and scientists have been unsuccessful in their attempts to control the parakeet population, so they are asking for help. Residents and visitors alike are asked to call 855-Kauai-RRP when they discover a parakeet roosting area. Please do not report sighting one or a few birds. Researchers are actively looking for places where large numbers of birds gather for a night’s rest. That’s when to call.

Fig Trees
Kauai has no native fig trees. About a century ago, fig trees were intentionally brought to the island along with their pollinators. It was an action that introduced two invasive species: the trees and their insects.

To produce fruit, a fig tree must have a specifically matching pollinator. For instance, a Port Jackson fig tree is only pollinated by a Port Jackson wasp. This rule has been unbreakable since the first fig tree met the first pollinating wasp, although an exception to the rule was recently discovered in Kauai.

The flowers of the fig tree are encased in the fruit, so the tiny wasp must wriggle through an almost unseen opening to get inside. She then inserts a fertilized egg into each flower. There, the eggs develop until the new wasps are ready to hatch. The egg layer never leaves because the opening seals up, trapping the female inside the fruit.

But don’t worry. The little crunch you experience when eating a fig isn’t caused by the remains of a wasp; it is seeds. Fig trees produce an enzyme, ficin, that digests protein, dissolving the wasp’s body, and reusing the nutrients. So, the fig tree is, in effect, carnivorous. Who knew?
Unlike the problem parakeets, the adverse consequences from the tree’s introduction to Hawaii have been minimal, and commercial growers have benefited by having income from yet another product; fast growing, and delicious figs.