August is wedge-tailed shearwater chick hatching time at Kīlauea Point NWR. This grayish-brown seabird, called ʻuaʻu kani in Hawaiian and “wedgie” for short in English, is one of the most common seabirds found in Hawaiʻi. They generally mate for life and pairs tend to come back to the same nesting spot each year. ʻUaʻu kani are burrow nesters. Pairs begin cleaning and excavating their burrow upon arrival in March and old burrows that have been in use for many years can extend more than 5 feet in length. Some pairs nest above ground underneath shrubs such as native naupaka or akoko, or nestled within the exposed roots of ironwoord or other trees.
After 53 days of life inside a white, chicken-sized egg, the chicks hatch out. When they emerge, they are small, gray little fluff balls, once they’ve dried off. They will be fed regurgitated squid and fish oil by both parents for about three and a half months before its time for them to leave the nest. Like most seabirds, the first years of an ʻuaʻu kaniʻs life is spent entirely at sea, fishing and resting on the ocean. When they do return to land to begin breeding, they tend to go back to where they hatched.
The ʻuaʻu kani population at Kīlauea Point NWR has benefited immensely since the land came under the protection of the Fish and Widlife Service as a national wildlife refuge. In the late 1970s (prior to Kilauea Point being designated as a refuge) an island-wide survey counted 3,855 burrows along Kauaʻi’s coastline, 75% of which were on Kīlauea Point. In the mid 2010’s FWS Biologist Brenda Zaun estimated that there were 8,000 to 15,000 breeding pairs on the refuge alone. Biologists from the US Geological Survey conducted a survey this summer, but the results have not yet been released yet. Predator control on the refuge has been a major benefit to the population, but limiting access to people was critical too. Many people who accessed the areas before it became a refuge didn’t even realize there were birds beneath their feet and sometimes unwittingly crushed and trapped birds or eggs in collapsed burrows.
Extreme weather events can be very impactful for shearwaters and other ground nesting seabirds. Sudden and torrential rains can cause mudslides on the slopes, flooding burrows and burying openings. Chicks being raised in surface nests risk getting soaked in long, heavy downpours. The damage to ʻuaʻu kani and other seabird nesting areas was very evident following the torrential rains that hit Kīlauea Town recently. Many burrows were buried in mud and a number of unhatched eggs washed downslope.
In spite of some of the challenges they face, ʻuaʻu kani nesting at Kīlauea Point NWR will fare better than many seabirds which nest out on remote Pacific islands. In time, rising ocean levels due to climate change will encrouch into nesting grounds that millions of seabirds rely on for reproduction. As they become displaced, some of those birds will likely make Kīlauea Point NWR their home too. For this season, though, we hope that the precious birds which survived this recent storm make it through the next few months until it is their time to fledge and soar.