Vaishampayana while narrating Hayagriva story details how Brahma worshipped Narayana. In that Brahma says:
As regards myself, I have sprung through thy Grace. From thee have I derived my birth. My first birth from thee, which is regarded sacred by all regenerate persons, was due to a fiat of thy Mind. My second birth in days of yore was from thy eyes. Through thy Grace, my third birth was from thy speech. My fourth birth. O puissant Lord, was from thy ears. My fifth birth, excellent in all respects, was from thy nose. O Lord, My sixth birth was, through thee, from an egg. This is my seventh birth. It has occurred, O Lord, within this Lotus, and it is meant to stimulate the intellect and desires of all the beings.
What does "birth" here means? Is it Brahma's birth at the start of each kalpa? If so why only 7 births as Brahma is said to be 50+years old.