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Threats to the Birds and their Habitat

Threats come in many forms, some very surprising. Here we have listed the main threats, and we are in the process of filling in the details with text and pictures. Please check back often over the next few weeks.

Natural Threats


Avian Botulism - fact sheet from the USGS National Wildlife Health Center.
West Nile Virus - fortunately not found in Hawaii YET.
Avian Pox -
Algae Blooms -

Predators - Endemic

Black-Crowned Night Herons
Frigate Birds
( `Iwa Birds)
- a three-foot barracudda can easily swallow a chick
- the most unexpected threat to the birds, check out the pictures.

Predation from Introduced Species

Rats - The biggest threat to the marsh inhabitants.
Mongoose - We have also trapped mongoose, which eat eggs and chicks.
Cattle Egrets - sometimes flocks of 50 or more will decend on the marsh.
Bullfrogs - in some preserves on Oahu, they are the #1 predator of stilt chicks. We are actively trapping bullfrogs at Kaelepulu.

Invasive Plants

Mangrove - in the past year more than 3,000 pounds of mangrove have been removed. It requires monthly maintenance.
Pluchia and Grasses
- fast growing and very invasive
Papyrus -
- the most common plant currently found on the wetland islands,

Man-Made Threats


Street Run-off - including motor oil and soap from washing cars.
Fertilizers -
common garden fertilizers can be toxic to the birds.
Draining Swimming Pools -
although against the law, it still continues.

Release of Pets

Aquarium and Pond Fish -
Turtles - Read-Eared Slider Turtles are now common in the wetland


Seven storm drains empty into the wetland. Run-off carrying dirt, rocks, and silt flows into the wetland with every rain.

Monofilament Fishing Line and Nets

Tangled fishing line and nets can trap birds, eventually killing them if they are unable to feed or escape from predators.


You wouldn't think a bird preserve would be threatened by hunting, but in the Spring of 2005 a Koloa Hybrid duck was found shot. This was confirmed by the Fish and Wildlife lab in Madison, Wisconsin.


In the past year we have collected well over 250 Spray Paint cans from the wetland. They usually appear after a heavy rain, washing down the storm drains. These cans lodge in the vegetation and rust, and the toxic contents leach into the wetland.

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