Zebra and gouldian finch breeding differences

[E Orix]

If I started off with 4 pair of Gouldians and 4 pair of Zebras in January by June I am reasonably sure that the Gouldians would have fledged possibly twice if not more young on the perch than the Zebras.By December the Zebras may have caught up. By the end of the next year the Zebras would be far ahead even though the Gouldians have had another season.The reason in captivity Zebras will breed all year and before the year is out the sons and daughters and most likely grand sons and grand daughter will all be breeding.
They are at the bottom of the food chain so their life expectancy is very short in the wild.
The Zebra finch is a lovely bird,sadly I can't risk population explosions so I have 2 normal male Zebs in my big flight and that works well for me.