This is what I call the 5th period:
We have just passed the apex of the month, full moon. Now we are going downwards. The 'face' of the moon has changed as the sun now shines on it from the opposite direction. And in the 4th glyph (from the left) the 'tired old bird' has also reversed its direction. The 'moonish' appearance of the tail in the fish (5th glyph) is now more pronounced than before and the fish is hanging upside down compared to its earlier direction, also a sign of inverson. Exhausted as we are from the intense Full Moon period there is now - as I read the text - 5 tapu-free nights, all 5 being glyphs of ordinary appearance.
In the 1st glyph the bird has grown up which we can see from its beak, the experiences of the 4th period having taken its toll. And the inverted tired old bird (glyph no. 4) does also show signs of old age. Its beak is longer than ever. May we not from this assume that a long beak indicates 'long' age and a short beak 'short' age? Even the 'Clara-knife' (in glyph no. 2) seems longer than usual.
The strange 3rd glyph is basically a moon, that is quite clear. And this moon is divided into two parts, the upper part hatched which (I imagine) means darkness (or rather shadow). The word 'hatch', though, also means to get out from the darkness inside the egg. Is the full moon a sort of egg? The 3rd glyph contains many signs. The hatched area is not limited downwards by a horizontal short line, but by a line which is oblique. And the hatching lines are also oblique, though in another direction: But the one at the top seems to have the same direction as the line of demarcation between dark and light.
On the outside of the perimeter of the moon (in the 3rd glyph) there are 3 half-suns and 1 half-moon, as I read it. And the half-moon is connected to the shadowy part. Two of the half-suns are also connected to the shadowy part, one to the light part. I guess this means that the dark part represents the Waxing Moon, now in the shadow and 'dead' (shown by the half-moon = a broken canoe). The 3 half-suns and the complex hatchmarks I will not try to comment for the moment.