Ae‘o (Hawaiian Stilt) Eggs and Nesting Behavior
The Ae‘o (Hawaiian Stilt) (Himantopus mexicanus knudseni) is an endangered wading bird found in Kaua‘i and throughout Hawaii’s wetlands. Their nesting habits and eggs are particularly vulnerable to threats, making conservation efforts crucial for their survival.
1. Nesting Season and Habitat
• Breeding Season: April to August, with peak nesting in May and June.
• Preferred Nesting Sites:
• Shallow wetlands, mudflats, salt ponds, and fishponds.
• Coastal lagoons, marshes, and protected inland ponds.
• Freshwater or brackish areas with open ground and minimal vegetation for visibility.
In Kaua‘i, Ae‘o commonly nest in Hanalei National Wildlife Refuge, Menehune Fishpond, and Kaua‘i Lagoons Wildlife Sanctuary.
2. Nest Characteristics
• Nest Type: Simple ground scrapes—shallow depressions in mud, sand, or gravel.
• Nest Materials: Lined with small twigs, grass, pebbles, or shell fragments for camouflage.
• Nesting Locations: Often placed on small islands or elevated areas to avoid flooding and predators.
3. Ae‘o Eggs
• Number of Eggs: Usually 3–4 eggs per clutch.
• Egg Color & Camouflage:
• Light tan, olive, or brownish with dark speckles to blend into the ground.
• The camouflage helps protect them from predators and human disturbance.
• Egg Size: About 1.5 inches (3.8 cm) long.
4. Incubation & Parental Care
• Incubation Period: 21–25 days, with both parents sharing responsibilities.
• Parental Roles:
• Both male and female take turns incubating eggs.
• Parents aggressively defend the nest, using alarm calls, dive-bombing, and “broken-wing” displays to distract predators.
• Chick Hatching:
• Hatchlings are precocial, meaning they hatch with downy feathers and can walk/swim within hours of hatching.
• Parents lead chicks to shallow water to start foraging immediately.
5. Threats to Ae‘o Eggs & Nesting Success
Natural Threats
• Tidal Flooding & Heavy Rains – Nests in low-lying wetlands are vulnerable to storm surges and sea-level rise.
• Predators – Eggs and chicks are preyed upon by:
• Feral cats, mongoose, rats, dogs, and barn owls.
• Invasive bullfrogs may also eat small chicks.
Human-Caused Threats
• Habitat Destruction – Wetlands are being drained for development, agriculture, and resorts.
• Disturbance from Humans & Pets –
• Off-road vehicles, hikers, and dogs can trample nests or scare away parents, leaving eggs exposed.
• Loose dogs may chase or eat chicks.
• Pollution & Pesticides – Contaminants in water can harm developing embryos or reduce food availability.
6. Conservation Efforts to Protect Ae‘o Eggs
• Wetland Protection & Restoration – Maintaining safe nesting areas in wildlife refuges.
• Predator Control Programs – Removing feral cats, mongoose, and rats from breeding areas.
• Raising Public Awareness – Encouraging responsible birdwatching, leash laws for dogs, and habitat conservation.
• Nest Monitoring Programs – Wildlife organizations monitor nests and protect vulnerable sites.
7. How You Can Help Protect Ae‘o Eggs in Kaua‘i
• Stay on Marked Trails – Avoid disturbing wetland nesting sites.
• Keep Dogs on a Leash – Prevent pets from chasing birds or disturbing nests.
• Support Wildlife Refuges – Donate or volunteer for wetland conservation programs.
• Report Nest Disturbances – If you see damaged nests or threats, notify Hawai‘i Division of Forestry & Wildlife.
The Ae‘o (Hawaiian Stilt) is a delicate and endangered bird, and protecting their eggs is crucial to their survival. Their simple ground nests make them highly vulnerable to predators, habitat loss, and human disturbance. Conservation efforts across Kaua‘i are helping to restore wetland habitats, reduce predator threats, and educate the public to ensure that future generations can continue to witness the graceful Ae‘o wading through Hawaiian wetlands.
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