Hi, are you referring to the Spanish edition of the book? Unfortunately I don't know the Spanish crochet terms, but this is the instruction for round 4 of the black part of the beak in English:

Rnd 4: (sc in next 8 st, ch 5, work back down the ch you just created, skip first ch on the hook, sc in next 4 ch, sc in next unworked st on round 3) repeat 2 times [34]

I hope this helps you out, enjoy crocheting!