Tuesday September 21, 2021
This season's wedge-tailed shearwater have hatched- and they are super cute!
With the albatross out at sea the wedge-tailed shearwater are looking after the nesting bluff.
Wedge-tailed Shearwater (Ardenna pacifica) are one of the most common seabirds in Hawaii and the largest of the tropical shearwaters. The species has two color morphs: dark and pale. The pale morph has plumage that is grey-brown on the back, head and upper wing and white plumage on the underside. The dark morph has plumage that is grey-brown over their whole body.
Their common name is derived from their large, wedge-shaped tail which is believed to help them glide long distances. Their Hawaiian name is 'ua'u kani which means moaning petrel deriving from their vocalization which sounds like deep moaning or groaning.
Wedgies are monogamous and return to the same nest site in March of each year. They nest in shallow burrows of one to two meters in length and lay just one single egg per season. Egg laying happens in early June and incubation on average lasts 52 to 55 days. Both parents alternate egg shifts where one shift on the egg can last up to 12 days!
Their chicks begin hatching in late July, just as the last albatross chicks are fledging. Wedgie parents forage at sea and regurgitate fish, squid and stomach oil to their growing chicks who are fed every 24 hours. Wedgie chicks fledge in November just as the first albatross are returning for their nesting season.The average hatch to fledge time frame is approx 100-115 days. Parents leave the chick shortly before it fledges and the chick becomes independent of its parents.
Wedge-tailed Shearwaters are easily spotted on Kauai during their breeding season of March to November. Their species population is stable, listed by IUCN as "Least Concern" unlike the Newell Shearwater which also nest on Kauai but in higher elevations and are listed as "Critically Endangered".
Wedgies may have a stable population however they are still subject to many threats:
- Predation: by feral cats, pigs, rats, mongoose and owls
- Trampling: nesting burrows are shallow and often trampled over by cattle and humans collapsing their burrow
- Plastics: they are ocean feeders and inadvertently ingest marine rubbish
- Habitat destruction: they are coastal nesters and face threats of rising sea levels, construction and invasive plants
- Overfishing: they mostly rely on larger predatory fish to drive prey (smaller fish and squid) to the surface
- Artificial Lighting: bright outdoor lights such as street, resort, ballpark and construction lighting can disorient fledglings causing them to fall to the ground exhausted or collide with structures, this is called “fallout”
- Fallout: collision with structures, powerlines or vehicles caused by disorientation from bright lights
How to help
Eliminate outdoor lights at night and keep an eye out for grounded birds. If you see one, gently pick it up with a towel and please take it to the nearest Aid Station. Visit Save Our Shearwater for rescue how to’s and the nearest Aid Station drop off to you.