The sooty tern, or 'ewa'ewa, is a miniature replica of the 'iwa and reputed to be the fastest flyer. Among the various species of aku birds, the sooty tern has a unique behavior. Through the ages, aku fishermen have studied the bird's behavior and learned to anticipate the aku's movement.
It is common for aku to feed at the surface for only a short while before the fish dive deep. When the aku dive deep, the sooty terns will cluster high above in the sky and soar around to wait for the fish to resurface. If the fish will not resurface soon, the sooty terns will fly off and not wait like some other sea birds that sit on the water. If the fish resurface, the sooty terns, being fast flyers, are some of the first birds to react to the aku's feeding action. Fishermen, being aware of the sooty tern's behavior, keep a watchful eye on them.
Two species of noddy tern (noio) are common to the main Hawaiian Islands. Of the various species of aku birds, aku fishermen considered the noio the "true" aku bird. Whenever there was a flock of birds associated with a fish school, invariably the flock that included noio was associated with an aku school.
Fishermen with experience recognized the noio as the key bird indicating the exact location of the aku. The noio has a habit of hovering immediately above the aku, whereas other species of seabirds meander to and fro over the school and do not provide the fishermen clues to the exact location of the fish.
The bird commonly referred to by fishermen by the name matori is primarily the wedged-tail shearwater. The wedge-tail shearwater is the most abundant seabird in Hawaii. Feeding characteristics of matori include the formation of floating rafts. The birds use this strategy to attract baitfish below them.
The movements of the birds will also help you determine the best position. Matoris (shearwaters) will tend to "walk on the water" when the ahi are close to the surface feeding and will swoop from side to side when the fish are down deep. Sooty terns will fly high when the fish are deep and will make a mad dash for the water when the fish are ready to bust. 'Iwa (great frigate birds) and "whites" (boobies) will also make radical movements toward the water when they see the fish rising. If you can time your pass according to these signs, you'll be in the right place at the right time.
First, you have to know how to find the birds. If you get an early start, you usually can get yourself into a line of birds that will act as an excellent road map. From all indications, birds usually start their day off searching for food in the area where they last left the schools they worked the day before. Whether it was a school associated with rubbish or schools of fish traveling down a current line, the birds can tell you where to start looking.