Ideas:

This is the bird we recognize from Sunday, Thursday and Saturday. Bu it has a sign in the form of slightly outward pointing wingtips.

In view of my opinion that this type of bird (without the sign just mentioned) often represents the Sun God at zenith, the following information could be of value:

"Fifteen days after the appearance of the moon it reaches the turu stage. Fifteen days after the turu stage it becomes mutuwhenua - that is, the moon is overcome by the sun, which carries it off into darkness. When abandoned by the sun it appears again." (Makemson)

Are the bent tips of the wings showing that the Sun Bird is just about to lift and carry off the Moon into darkness?

But then this glyph ought to have been placed later in the calendar. Therefore the glyph perhaps instead is showing the Sun Bird arriving to court the Moon before abduction.