You Do Need power plug adapter while traveling from Pitcairn Islands to Cape Verde.

Here is Why You Need An Adapter

The outlet and plug type used in Cape Verde are C and F and in Pitcairn Islands is I. This is how they look like.

Pitcairn Islands

In Pitcairn Islands, outlets of type I are in use.

Type I

Cape Verde

In Cape Verde, outlets of type C and F are in use.

Type C

Type F