Almost all of the islands in the Hawaiian chain are home to a variety of seabird species. Some islands are home to more than others, depending on the habitats available on each particular island. Mahi mahi seems to attract several species of birds.
If you start your day with trolling, the birds will be your guide. During the ahi season, the matori (shearwaters) and ‘Iwa (large frigates) will usually be good ahi indicators, and large piles will often lead you to your pot of gold. Biting the fish is another story, but birds can help you find the ahi. Often these piles of birds will have a mixture of “white” (boobies), sooty terns and other species as well.
If the birds have a good idea of where the fish are, they will likely fly low toward the water in a specific direction. The frigate bird, or ‘Iwa, due to its size and flight pattern, is an easy bird to identify. The ‘Iwa is considered to be the meanest and ugliest bird among all seabirds. This large bird is frightening in appearance, and it terrorizes other seabirds and steals their food. Although preying on other seabirds is the Iwa’s primary feeding technique, it can sometimes hunt and catch its own meal. It is not uncommon for the ‘Iwa to follow a concentration of large predators. For example, mahi mahi are often schooled and one of their favorite prey is the flying fish, or malolo.
When the malolo fly away to escape the mahi mahi, the ‘Iwa descends and snatches the prey in the air. When the ‘Iwa are soaring high in the sky and appearing to be gazing into the water, they are probably stalking a school of top predators.
The unusual abundance of ‘Iwa presaged an abundance of large baitfish and an abundance of large predators in the pelagic ocean. The ‘Iwa is one of the best indicators for projecting what type of tuna season to expect.
“Iwa often waits for the mahi mahi to chase the bait out of the water before moving. They hover over a school and wait for their opportunity. Because ‘Iwa cannot land on water like other ocean birds, this is one of the ways they can feed.
‘Iwa follows both open schools and schools associated with floating debris. When you see them floating in the air currents above the water, they’re probably still looking for lunch. However, if they start to dive in and make exaggerated movements, obviously they have something in sight.
‘Iwa has the ability to see fish deep below the surface and can time their dives so they can shoot a fish trying to get away from a predator like a hungry mahi-mahi. They are excellent indicators of mahi mahi, especially if there are other birds that work with them.
You can often tell when an ‘Iwa is about to melt by the movement of its tail. The bird’s tail often extends into a wide “V” and shrink again just before a dive. Little things like this should signal you to take action.