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Feathers in the Garden: Avian Influenza Awareness in Hawaii's Landscapes

Posted on Jul. 1, 2025  /  Subscribe 0

By: Yunuen Bustamante, Melelani Oshiro and Asia Broussard

Introduction: Productive Landscapes and Emerging Challenges

Hawaii’s climate and natural resources make it an ideal environment for productive gardens, urban green spaces, and community orchards. With consistent sunshine, ample rainfall, and a year-round growing season, the islands support a wide range of public and private landscapes—from residential yards to parks, school gardens, and commercial orchards. Currently, the Hawai‘i Department of Land and Natural Resources (DLNR) manages approximately 30,000 acres across 51 state parks (DLNR, 2025).

To address urban food security, the City and County of Honolulu has designated 10 community gardens with a total of 1,248 plots for food production and community forestry initiatives (City and County of Honolulu, 2025). This is especially critical on Oahu, where nearly 90% of the state’s population—approximately 998,747 people—reside (US Census, 2024). As urban density increases, edible landscapes offer a promising strategy to enhance food resilience, social cohesion, and environmental sustainability (Yang, 2025).

The Rise of Feral Chickens in the Urban Ecosystem

While these green spaces promote health and food access, they also create favorable habitats for feral chickens. Although often seen as a cultural curiosity or tourist attraction—particularly in Kauai—feral chickens have become prevalent across all islands.

While domestic chickens were originally introduced in the late 18th century, chicken populations have expanded significantly as the population grows in Hawaii (Figure 1). Hatcheries such as Asagi Hatchery, operating since 1935, continue to supply chicks to backyard producers (Martin, 2023). Natural disasters such as Hurricanes Iwa (1982) and Iniki (1992) further contributed to the growth of feral populations, as domestic birds escaped into the wild and reproduced without containment (Johnsson et al., 2016).

Figure 1. Feral chickens are a nuisance and health concern in urban areas of Hawaii.

Feral chickens can disrupt agricultural and landscape systems by scratching up roots, displacing mulch, damaging crops, and contaminating soil with droppings. Although chicken manure can be a valuable fertilizer when composted properly, unmanaged feces in public or edible landscapes may pose sanitation and zoonotic disease risks (City and County of Honolulu, 2025).

Backyard Poultry: An Asset for Urban Food Security

Despite the complications introduced by feral chickens, domesticated poultry remains a vital asset in addressing food insecurity. A 2025 study in Mexico showed that 98% of households engaged in small-scale livestock and crop production reduced their food expenses by 10% to 50% (Bautista, 2025). Backyard hens require limited space, can consume household food scraps, and provide a consistent source of fresh eggs.

Bautista (2025) also found that 86% of eggs produced in these systems were consumed within the household, underscoring their importance in local diets. The revised ordinance of Honolulu (Chapter 12, Article 2.5) permits up to two chickens or peafowl per household—preferably hens—for non-commercial use (American League Publishing, 2024). Daghir, in 2021, recommends governments should facilitate and enhance poultry production in the backyard since poultry products are an excellent source of good-quality protein (Figure 2).

Additionally, chicken manure, when appropriately composted, is also a high-value, nitrogen-rich fertilizer. A 2025 study by Kenth demonstrated that ginger crops fertilized with composted chicken manure achieved yields comparable to those treated with synthetic fertilizers while improving soil health through added micronutrients and organic matter, up to 16%. This highlights the potential of poultry waste to enhance productivity in sustainable and regenerative agricultural systems.

Figure 2. Domestic chickens provided meat and eggs. A significant source of protein for a household.

Public Health and Avian Influenza: The Intersection of Landscapes and Disease

However, the close interaction between feral birds, domestic poultry, and native wildlife (Figure 3) has led to increased concern regarding public health risks, particularly concerning the transmission of Highly Pathogenic Avian Influenza (HPAI).

Highly Pathogenic Avian Influenza (HPAI, specifically H5N1) is a deadly viral disease of birds that has recently been detected in Hawaii. In domestic poultry, HPAI strains are usually fatal, often causing rapid, widespread mortality in flocks.

Once introduced, HPAI can spread rapidly among domestic poultry, symptoms in chickens and ducks include sudden death (often with no prior illness), labored breathing, swelling of the head and neck, runny nose, diarrhea, and sharp drops in egg production (HDOH, 2024). Importantly, migratory waterfowl (ducks, geese, shorebirds) often carry H5 avian influenza without obvious illness (HDOA,2025). When wild birds infected with H5N1 mingle with or contaminate areas where poultry feed, water, or bedding, the virus can spread to domestic birds (for example, via droppings or shared equipment) (HDOA, 2025).

In November 2024, Hawaii confirmed its first HPAI (H5N1) of the current global outbreak. A backyard bird sanctuary in Wahiawā, Oahu, where the sudden deaths of around 20 ducks led to the euthanization of over 70 birds, including ducks and zebra doves (Miyashima, 2024).

Around the same time, a single wild duck in North Shore Oahu was found with HPAI (HDOA, 2025). Genetic analysis shows these Hawaiian strains are of the Eurasian lineage typical of migratory-bird outbreaks (not the same as some recent mainland U.S. strains). Hawaii lies along the West Pacific Flyway and intersects with major migratory corridors such as the East Asian–Australasian and Pacific–American Flyways in Alaska (Figure 3). Migratory birds who arrive in the Hawaiian Islands seasonally may asymptomatically shed the virus via saliva, nasal secretions, and feces (CDC, 2024).

Figure 3. Highly Pathogenic Avian Influenza contagious sequence.

Figure 4. Map of bird migration flyways and effects of highly pathogenic avian influenza A (H5N1) spread (EAAFP, 2022).

Managing Risk: Landscape Strategies and Community Interventions

Reducing the risk of avian influenza requires coordinated action from landowners, gardeners, farmers, and community stewards. Although we cannot eliminate migratory bird pathways, we can implement practices that limit cross-species transmission, reduce feral bird congregation, and improve biosecurity.

Table 1. Recommended practices for community gardeners, home gardeners, urban landscapes, and domestic poultry owners to prevent feral bird damage and poultry biosecurity.

Conclusion

Hawaii's unique blend of urban agriculture, backyard poultry keeping, and abundant green spaces presents both remarkable opportunities and pressing challenges. While community gardens and home flocks contribute meaningfully to food security and sustainability, the rise of feral chickens and the threat of Highly Pathogenic Avian Influenza (HPAI) highlight the importance of vigilance, collaboration, and informed action. The intersections between human activity, wildlife, and domestic animals demand integrated approaches that prioritize both ecological balance and public health.

By adopting practical biosecurity measures, promoting responsible poultry management, and fostering community engagement, we can protect the health of our flocks, our gardens, and our neighbors. Education and policy development will be essential to building resilient landscapes that continue to nourish our communities while preventing the spread of zoonotic diseases like HPAI. Working together, Hawaii can lead by example in cultivating safe, sustainable, and thriving urban ecosystems.

References:

American League Publishing (2024) Honolulu, HI. Code of ordinances. Chapter 12 Article 2.5. https://codelibrary.amlegal.com/codes/honolulu/latest/honolulu.

American Veterinary Medical Association AVMA (2025) Avian Influenza. https://www.avma.org

Bautista, H., Rodríguez, J., Romero, Y., Sánchez, F., Fernández, L., (2025) Agricultural Backyard Production in the Food Security Framework: A Case Study of a Microregion of Chicontepec Veracruz, Mexico. Agro Productividad. 10.32854/agrop.v18i1.3104. 

City and County of Honolulu (2025) Community Gardening with the City and County of Honolulu. https://www.honolulu.gov/dpr/volunteer-give/community-gardening.

Daghir, N., Diab-El-Harake, M., Kharroubi, S. (2021) Poultry production and its effects on food security in the Middle Eastern and North African region, Journal of Applied Poultry Research, Volume 30, Issue 1, 2021, 100110, ISSN 1056-6171.

Department of Land and Natural Resources DLNR (2025) About our parks. https://dlnr.hawaii.gov

East Asian-Australasian Flyway Partnership (EAAFP) 2022. What is a flyway? https://eaaflyway.net/the-flyway.

Hawaii Department of Agriculture HDOA (2025) Increased biosecurity urged to protect birds from avian influenza. https://hdoa.hawaii.gov/blog/main/nr25-02birdbiosecurity.

Hawaii Department of Health HDOH (2025) DOH closely monitoring detection of h% avian flu in Kauai   wastewater.https://health.hawaii.gov/news/newsroom/doh-closely-monitoring.

Hawaii Department of Health HDOH (2024)Avian influenza confirmed in backyard flock of birds https://health.hawaii.gov/news/newsroom/avian-influenza-confirmed-in-backyard-flock-of-birds/

Johnsson, M., Gering, E., Willis, P., Lopez, S., Van Dorp, L., Hellenthal G. et al. (2016) Feralisation targets different genomic loci to domestication in the chicken. Nat Commun 7(1):1-11.

Kenth, D., Antesco, S., Bunquin, M., Ventura, A., Bryan, J., Lawas, E., Almontero, C., Rodrigo, R., Tayobong, P. (2025). Effect of Chicken Manure on the Growth, Yield, and Soil Quality in Containerized Ginger Cultivation System.

Martin, M., López, S., Van Dorp, L., Hellenthal, G., Johnsson, M., Gering, E. Henriksen, R., Wright, D. (2023). Population structure and hybridisation in a population of Hawaiian feral chickens. Heredity. 130. 1-9. 10.1038/s41437-022-00589-z.

US Census Bureau (2024). QuickFacts Honolulu County, Hawaii. Population estimates July 2024. https://www.census.gov/quickfacts/fact/table/honolulucountyhawaii

Yang, H., Hussein, M., Ibrahim, R., Lyu, R. (2025). Trends in urban edible landscapes: a comprehensive bibliometric analysis. Environmental Research Communications. 7. 10.1088/2515-7620/adac34.

Yunuen Bustamante and Melelani Oshiro are Extension Agents at the Department of Human Nutrition, Food and Animal Science at the University of Hawaii at Manoa, College of Tropical Agriculture and Human Resources. Asia Broussard Livestock Hele Imua intern at the Urban Garden Center, under Bustamante's supervision, as part of a program from the Department of Labor and Industrial Relations.

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