Photo by Nathan Banfield, KESRP

Threats to Covered Species

Seabirds like the Newell’s shearwater, or ‘a‘o, and Hawaiian petrel, or ‘ua‘u, have a very interesting and complex life history. They hatch in a deep burrow, dug into a steep mountain side, nestled among native ferns and other native plants. They are actively fed by both parents, who have a pair bond, and will return to the same nest year after year to breed together. When the chick is large and strong enough, it will fledge (leave the nest), and head out to sea, where it will remain away from land from the next 2-3 years of its life, feeding and ranging widely across the open ocean. Between the ages of 2-5 (sub-adult), the bird will begin to make trips back to the breeding colony where it was born, and will begin to look for a mate and “prospect” for a place to dig a burrow of its own. By age 6 (adult), these long-lived birds begin to nest, and will lay 1 egg per year, potentially continuing to breed until the age of 30 years or more! They will return to the same mate and the same burrow as long as both birds are alive, breeding is successful, and the nest remains intact. These seabirds are also nocturnal, meaning they are active at night.

Unfortunately, many threats along the way prevent these seabirds from completing their life cycle…..

PREDATORS

Life history patterns evolved when the Hawaiian Islands were free of land-based predators. Ground nesting makes these seabirds very vulnerable to introduced predators such as rats, feral cats, pigs, and mongooses. In fact, the absence of mongooses from Kaua‘i may explain the larger numbers of ground-nesting seabirds found here, including ~90% of Newell’s shearwaters. Many eggs, chicks, adults and prospecting sub-adults are killed each year by these predators, which are found in even the most remote nesting sites. Animals such as feral pigs not only predate on seabirds, but can also destroy their burrows and surrounding habitat. 


LIGHT ATTRACTION

The chicks leave their nest (fledge) in the fall, undergoing a one-time nocturnal migration from their mountain nests to the sea between the months of early October and early December. Every year on Kaua‘i, several hundred fledglings are attracted to bright lights during their night-time migration to the sea. Upon flying closer to the attractive lights, they begin to circle around them repeatedly. Eventually they either land on the ground due to exhaustion or they collide with nearby wires, buildings, or other structures as they circle the lights. Once on the ground, the birds are unable to become airborne again without a proper slope or clear air to take off, and they are at high risk of death from predators, vehicles or starvation.

LINE COLLISION

At low elevation, adult seabirds are much less likely to be attracted to lights. Adult seabirds, however, migrate back and forth on a daily basis during chick rearing, bringing food to their immobile young in the burrow. Thus adults have many more opportunities to collide with powerlines or utility structures. And the death of a breeding adult will often mean the remaining chick is undernourished and unable to successfully fledge. Just as with the downed fledglings, the adult seabirds cannot take off directly from the ground without a clear area. Thus they are subject to high mortality caused by automobiles, dogs, cats, and starvation.


The phenomenon of seabirds falling to the ground during the night due to light attraction has been termed “fallout”. This can actually occur at all life history stages, but primarily affects fledglings and a smaller portion of adults that fallout due to collisions.


The fallout period during the autumn months was first noticed in the 1960s with increased tourism development on Kaua‘i.  Between 1979-2015, more than 32,000 seabirds, mostly threatened Newell’s shearwaters, were recovered through voluntary public assistance in annual “fallout” rescue efforts known as “Save Our Shearwaters” (SOS – initiated by the DLNR and supported by KIUC). Kaua‘i’s SOS Program has succeeded for decades thanks to the community which assists greatly each fall with the rescue of downed seabirds. Unfortunately, it is estimated that less than half of the fallout birds are found each year (Ainley 1995). 


In the big picture, the U.S. Fish and Wildlife Service (USFWS) is the federal agency that is responsible for “recovering” the species, or finding solutions to the many threats that are causing species decline. The Recovery Plan for these seabirds was written in 1983, with subsequent 5 Year Action Plans helping to update the strategy for recovery by applying new information and new conservation tools.


The Kaua‘i Seabird HCP is not a recovery plan, but the conservation actions identified in the plan are based on the information from the USFWS on how to best help the seabird populations stabilize and increase. This HCP will identify ways to minimize light attraction problems during the fledging season. And to mitigate for the downed birds that cannot be prevented, it contains conservation actions to reduce predation on eggs, chicks, sub-adults and adults.  The hope is that through these multiple efforts, Newell’s shearwater, Hawaiian petrels and band-rumped storm petrel will thrive and continue to be an important part of the ecosystem on Kaua‘i!


That's great, but who should apply​?