Thursday, May 24, 2012

Mongooses and hive beetles, dark times for birds and bees

In a dark week for the birds and bees on Kaua`i, both mongooses and small hive beetles have been confirmed to be resident on the island.

Each is a serious pest with significant impacts on natural resources—the former to birds, and the latter to bees.

(Image: A blowup of a photo of the Kaua`i mongoose. Source: KISC.)
Invasive species specialists this week trapped an extraordinarily healthy male mongoose at the Kauai Lagoons area above Nawiliwili. An autopsy is planned, but the animal appeared large, fat and quite robust, said Keren Gunderson, project manager of the Kauai Invasive Species Committee (KISC).

A KISC press released reported that “a lactating female was discovered dead on Kaumuali`i Highway near Kalaheo in 1976, but none of the invasive animals have been found since then. However, there have been over 160 credible reports of sightings in the last 44 years, with over 70 in the last decade alone.”

Mongooses are serious predators, particularly of ground-nesting birds. At risk are our endangered waterbird species, including nene geese, ducks, gallinules, coots and stilts, but also barnyard birds, including chickens. (Some folks will cheer the possible impact on chickens, but the threatened loss of our healthy water bird populations is a major blow, since Kauai has been the last holdout for them.)

Other islands do have some of the native waterbirds, but in much smaller numbers than Kauai--likely in part because of mongoose predation.

The other new Kauai`i pest is the small hive beetle, a significant predator on honey bees. This small, brown-black beetle infests bee hives, and its larvae feed on bee honey and bee larvae.

Beekeepers noticed small beetles in hives during the past weekend and early this week and collected samples, which were submitted to the state Department of Agriculture for identification. The beetles are initially known to be at three separate locations.

“(Hawai`i Department of Agriculture) entomologists in Honolulu positively identified the submitted specimens as small hive beetle (Aethina tumida),” wrote Jacquie Robson, an apiary planner with the Hawai`i Department of Agriculture/RCUH Pacific Cooperative Studies Unit.

The small hive beetle is established on the other islands, where beekeepers must engage in time-consuming management activities to keep their numbers under control. Weak hives can be destroyed by the beetles.

The state Department of Agriculture was in the process of mapping infested hive locations, officials on Kaua`i said.

At risk are the island's small but growing honey industry, but more importantly the pollination services the bees provide to fruit, nut and vegetable growers, both backyard and commercial.

Since the animals are strong flyers, their spread across the island seems likely.

In the case of the mongooses, there have been numerous reports—increasing numbers since the trapping this week—at locations around the island. They’ve been reported from the south side of the island and the far north, and numerous points between.

It is too early to say categorically that they're established on the island, but the indications are not favorable for wildlife. The trapping of a healthy male, following a new flurry of mongoose sightings around the island, suggests the presence of a breeding population.

© Jan TenBruggencate 2012

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