Threats to Nēnē

Vehicle Traffic

Nēnē often explore new areas to nest and forage during the winter months causing potential collisions with motor vehicles. Numerous nēnē are killed each year with at least 5 dead in January 2023. Please be cautious when driving through areas where these birds are known to inhabit. There are numerous signs posted around the state along highways in known high-risk areas. We encourage drivers to be patient and be on the look out for nēnē. We are currently developing a collision prediction model using our sighting histories and real time dynamic traffic data to better estimate areas where these events are occurring and how we can better inform drivers to prevent nēnē fatalities.

Mongoose

Mongooses are weasel-like animals that were introduced to Hawaii in the 1800s by the sugar industry for the purpose of controlling rats in sugarcane fields. However, mongooses have had a significant negative impact on native birds, insects, and animals, and are estimated to cause $50 million in damages in Hawaii and Puerto Rico each year. They are known to prey on the eggs and hatchlings of native ground-nesting birds and endangered sea turtles, and have been blamed for the extinction of ground-nesting birds in Jamaica and Fiji. 

Mongooses are now widespread on the islands of Hawaii, Oahu, Maui, and Molokai, and are not found on Kauai or Lana’i. It is illegal to introduce, keep, or breed mongooses in the state of Hawaii without a permit, and fines for violations range from $250 to $1,000 per mongoose. If you see a mongoose on Kauai or Lana’i, you are encouraged to report the sighting to the appropriate authorities.

Cats

Feral cats are a significant threat to native wildlife in Hawaii, including the nene, or Hawaiian goose. In addition to direct predation on nene and other native species, feral cats also spread the parasite Toxoplasma gondii, which can contaminate the environment and harm birds, mammals, and humans. Feral cats are known to prey on endangered species and are recognized as a major source of mortality for birds in the United States. 

Toxoplasmosis is a particular concern for the conservation of endangered species like the nene, as well as the Hawaiian crow and monk seal. To address the threat of feral cats, it is important for pet owners to spay and neuter their cats, keep them indoors or safely contained, and microchip them for identification. Feral cats should not be fed and humane cat traps are available for loan from the Hawaiian Humane Society. Trapped cats can be brought to the society for spaying, neutering, and other health services, and should then be brought home as indoor pets, offered for adoption, or killed.

Humans

Nene are attracted to feeding opportunities provided by mowed grass and human handouts, and can become tame and unafraid of human activity, making them vulnerable to the impacts of various human activities. These activities include direct harm, such as that caused by vehicles and golf ball strikes, as well as possible disturbance by hikers, hunters, and other outdoor recreationists (Banko et al. 1999, pp. 23–24; Rave et al. 2005, p. 12; USFWS 2011a, p. 11; Hawaii Volcanoes National Park 2015, in litt.; Mello 2017, in litt.). Nene may also be impacted by human activities through the application of pesticides and other contaminants, ingestion of plastics and lead, collisions with stationary or moving structures or objects, entanglement in artificial hazards (e.g., fences, fishing nets, erosion control material), disturbance at nest and roost sites, and mortality or disruption of family groups through direct and indirect human activities (Banko et al. 1999, pp. 23–24; USFWS 2004, pp. 30–31; Work et al. 2015, pp. 692–693).