One of the surveys we do on the island is the Booby Mean Incubation Count (MIC). The purpose of the survey is to monitor and identify population size changes in three species of Boobies. We survey the Red-Footed Boobies, Brown Boobies, and the Masked Boobies. Only Red-Footed and Brown Boobies have been seen nesting on Johnston Island. Both of these species have only recently started nesting on the island. It wasn’t until 2006 after the military base closure. They are growing rapidly in response to the new non-military environment here.
We do this survey every 46 days for the Red-Footed Boobies and 43 days for the Brown and Masked Boobies. That is based on the incubation period for their chicks. If we do them in 43-46 day intervals then we have a greater chance of not counting the same bird twice. We only count active nests. That means that there has to be an egg or a chick in the nest to be counted and we only count the babies, not the adults.
The island is broken up into 22 sectors. We do a sector at a time and we walk in formation so that we don’t miss or recount birds. There were mostly Red-Footed Boobies, which makes it easier for us. They nest in trees so they are easy to spot. We use a chart with growth stages listed that are determined by feather growth. For example, an all naked bird is a 1. They would have just hatched. A chick with all downy feathers and half the size of an adult is a 4. And a fully feathered chick is a 9. We walk and check each nest.
Sometimes an adult is sitting on a nest and we can’t see inside. We use a tipping stick to tip the bird up a little to see if they are sitting on anything. We slide a stick just underneath the breast of the bird and pivot her on her heels to take a look. In this picture, Colin is tipping a Red-Footed Booby and found a stage 1 chick underneath her.
Other times we can’t see in the nest because it is too high. I am not 20 feet tall so I can’t tip the bird. We count those as “unconfirmed” nests. We counted hundreds of Red-Footed Booby nests and 3 Brown Booby nests in 2 days. I hope to see a Masked Booby nesting on Johnston Island before I leave in December.
Johnston Atoll Adventures 
How come the bird doesn’t freak out when you tip it?
They stay with their chick. Most of the time the adults fly away when you get too close. But they protect their chicks so they don’t fly off. They kind of just look confused while you tip them and then everything’s back to normal in just a few seconds.
Do they feed close enough to the islands for you to see? I watched an incredible video of a “congress” of Booby’s diving into the ocean. Made my jaw drop it was so amazing.
NO. THAT SOUNDS SO COOL. If I never see them fishing here, I will have to borrow that movie so I can see!