eldridgebrood
Chirping
Can you tell for sure by their quacks that they're females? Chances are pretty good they are if you also have a drake. If one or both of the Pekins were male, your existing one would probably have been going after them already.
None of my ducks make a whole lot of noise, but when the pekins do its loud and sounds like the traditional "quack". My rouen drake is still young (15 weeks), amd only within the last week actually knew he was a "he". So he may or may not go after them yet, he just very recently seemed to become more of the "leader" of the group over my female rouen mix.