Island hopping and butterflies

Saturday morning, the weather is supposed to let up and we leave Rosslyn
Bay early morning, headed for Head Island creek 56 milles away. The
trade winds are well established and we can sail all the way under genoa
alone. Along the way, no fish, no birds, no boats, nobody. We get there
around 4 in the afternoon. There is a shoal right in the middle of the
entrance and we choose to use the north entrance, as advised by Alan
Lucas in his cruising guide. A little hot for my taste. We have to sail
very very close to a line of rocks lining the north side in very choppy
waters with strong currents. We deal with it OK, and once we are inside,
very quiet and very calm. We pass two sailboats anchored close to the
mouth of the river and sail up to the second affluent to find an
excellent anchorage in a little bay. Super anchorage and excellent quiet
night.
We leave early next morning, with 47 miles to go to South Percy. Again,
no fish, except for a small hammer shark cruising slowly northward. No
birds either. But we are beginning to see butterflies, apparently flying
northward, coming from nowhere, and we wonder where they go, why, when,
where do they come from, what is the reason behind this behavior. No answer.
We get to South Percy again early afternoon, but we fail to find a
reasonably comfortable anchorage, despite visiting those recommended by
Alan Lucas. We end up anchored in front of the beach on the north west
side of the island, and the boat settles with stern to the wind, swell
on the beam and heading into the current. The roll is heavy and we spent
a miserable night there with the chain making all kinds of noise.
Unable to sleep well, we leave before daybreak, this time unfortunately
motoring, then motor sailing, but with only 34 miles to go.
As we get closer to Curlew Island, we see more and more of those
butterflies. And as we are rounding the northeastern corner of the
island, we pass a location on the cliff which is apparently the one spot
where they are all going. There is a dense stream of those butterflies
sailing across the boat as we pass the location, all going to the same
place while coming from slightly different directions. Very strange and
a mystery to us. If anybody has the answer to that, please let me know
at "brisegalets@mac.com".
This time, the anchorage is perfect. We are in front of the beach, but
the area is protected behind us by a drying shoal and the island having
a croissant shape, no swell of any significance can get in.
We anchored at noon, had lunch and took advantage of this calm and quiet
place to take a good nap to repair the lousy night of yesterday.
Tomorrow, we are headed for Refuge Bay in the Scawfell island, and maybe
we will see a few boats there. Right now, we are totally isolated with
no human activity in sight for the last two days.