We know that many of you are stuck at home, dreaming of Maui beaches, Haleakala hikes, and diving the Lanai Cathedrals. What you may not realize about some of your favorite Maui attractions is that they play a role in smaller ecosystems that make up a larger Coastal Ecosystem.
Here at Extended Horizons, we LOVE nerding-out about our local coral reef ecosystem, but we’re passionate about more than just our underwater friends! If you have ever been on one of our boat adventures, it is possible that we have pointed out native seabirds soaring above. Although some may be less-than-excited about spotting a seabird, Hawaii seabirds are no average seagull…they’re extra special!
Unlike Hawaii’s seabirds, seagulls and pelicans are land-dependent seabirds. They typically do not travel long distances across the sea and tend to stay close to larger land masses. Because Hawaii is thousands of miles away from the mainland US, gulls and pelicans won’t be found here. At least that means you’re able to enjoy a picnic at the beach without worrying about thieving birds…well maybe that’s not true…Hawaii chickens are another story!
Because we don’t have land-based seabirds like seagulls and pelicans, that means spotting seabirds near shore is actually quite rare! On the main Hawaiian islands, they are mostly seen while crossing larger channels of water or near cliff ledges. Hawaii is a great place for seabirds to nest, given that there are many protected areas on land and a whole lot of sea cliffs to shelter inside of. As you move further away from the Main Islands, the population of seabirds grows drastically, and it’s even possible to encounter some very rare and endemic species of seabirds!
While it may be unlikely to see rare species of seabirds from our boat (but not impossible!), we want to share a bit of information with you about the seabirds that we DO commonly encounter around Maui, so during your next visit, you can nerd-out about Hawaiian seabirds with us!
What is a Seabird?
Simply put, seabirds are birds that can live at sea. They have special characteristics and adaptations to allow them to take on the extra challenges that come with living in a marine ecosystem.
You can determine seabirds from non-seabirds in a number of ways. They typically have:
- Webbed feet – seabirds have webbed feet that allow them to more easily maneuver themselves in the water. Their webbed feet make them quick divers to chase down tasty fish!
- Dark or dull feathers – dark feathers have melanin that provide extra structural support. This makes seabirds’ feathers extra tough to withstand the environmental challenges of living at sea.
- Countershading – seabirds usually have dark feathers on the top of their bodies and light colors on their underside. This helps them camouflage from predators both above and below.
- Tube noses – for extra protection and to be able to have an increased sense of smell, many seabirds have tubes that surround their nostrils.
Seabirds We Commonly Spot from Our Boat
Our captains and dive staff do their very best to point out seabirds while we are out on our boat diving excursions. The seabirds that we most commonly encounter (in order of most to least common) are:
Brown Booby (‘Ā)
Sula leucogaster
Brown Boobies are the most-common seabird that we encounter on our boat. There are four subspecies of Brown Boobies worldwide, but only one is found here in Hawaii.
Population: 1,500 breeding pairs in Hawaii, 50-70,000 globally
Diet: They love to chow-down on flying fish, squid, mackerel scad, juvenile goatfish, and anchovy
Feeding: Typically, these birds will feed in groups both with those of their species and others as well
Nesting: Brown Boobies nest on the ground and typically lay 2 eggs per season
Hatching Season: September
Wedge-tailed Shearwater (‘Ua‘u kani)
Ardenna pacifica
The Wedge-tailed Shearwater is a native species of seabird. This species of seabird form mating pairs that typically mate for life.
Population: approximately 6,500 pairs (as of 2012) in Maui County and over a million pairs worldwide
Diet: Their favorite treats are goatfish, flying fish, squid, and squirrelfish
Feeding: Wedge-tailed Shearwaters feed by sitting on the surface and reaching down for fish, by diving down, and by flying low over the water and catching fish while flying
Nesting: Females usually lay one egg per season and both parents will care for their young until it’s able to face the world on its own
Hatching Season: June
Great Frigatebird (‘Iwa)
Fregata minor
Great Frigatebirds are large seabirds who gracefully dance through the skies. There are five sub-species of Frigatebirds worldwide, but only one here in Hawaii.
Population: 500,000 – 1 million individuals globally with approximately 10,000 breeding pairs in Hawaii
Diet: flying fish and squid
Feeding: They catch prey by flying over and dipping their bill into the water. However, Frigatebirds are known for being quite the thief, as they chase other birds and make them regurgitate their food to take it for themselves.
Nesting: Usually lay one egg every 2-4 years in low bushes. Unlike most seabirds, Great Frigatebirds typically have different partners each mating season.
Breeding Season: The beginning of mating season to the end of parental care can be about 2 years for Great Frigatebirds
Bulwer’s Pertrel (‘Ou)
Bulweria bulwerii
The Bulwer’s Petrel likes to spend its time at sea. They fly with short wing flaps, fluttering over the surface of the water before dipping to catch their prey.
Population: 75 – 103,000 breeding pairs in Hawaii. Only about 500 – 1,000 of those pairs are believed to reside on the Main Hawaiian Islands
Diet: They eat fish and squid, crustaceans and sea-strider bugs
Feeding: Foragers that likely fly over and dip into the water or by sitting at the surface
Nesting: Bulwer’s Petrels nest in rock crevices and their nests are very smelly. Breeding pairs seem to breed for life and both the male and female will incubate the eggs and care for the nestlings.
Breeding Season: May to October
White-Tailed Tropicbird (Koa‘e kea)
Phaethon lepturus
These beautiful seabirds are relatives of Boobies and Frigatebirds. Out of six subspecies of White-Tailed Tropicbirds, one is native to Hawaii. Their white-coloration and long tail feathers are distinguishing characteristics when viewing from below.
Population: 1,800 breeding pairs in Hawaii and less than 200,000 breeding pairs worldwide
Diet: relatively unknown but have been observed eating flying fish
Feeding: Usually forage alone but like to follow boats. They plunge dive for their prey from 50-60 feet above the water.
Nesting: Breeding pairs will dance through the skies as a courting behavior and typically nest in sea cliffs. Females lay one egg per season and both parents will care for the nestling
Breeding Season: March through October
As we said, these are some of the MOST COMMON seabirds that we encounter here, but there are so many more species that frequent Hawaii. If you want to learn more about the more rare and endangered species of seabirds, you can visit: https://www.mauinuiseabirds.org/
Threats
Now that you know allllll about our common seabirds and have fallen in love with them, let’s talk a little bit about their threats. Similar to sea turtles, seabirds are majorly affected by artificial light sources, such as street lights. Many seabirds make the voyage from their nest to sea during the nighttime and are believed to use the moon as a navigational tool. Some seabirds, especially young fledglings, are attracted to artificial light, and may be confusing our lights for the moon. When seabirds follow an artificial light source, they are directed into more urban, populated areas where they may run into buildings, power lines, or cars and are then injured or grounded. When seabirds are grounded in these urban areas, they are faced with even more threats, such as being struck by cars or attacked by cats.
Should you encounter a grounded seabird, please call 808-573-BIRD immediately.