Mardi Gras-a carnival held in some countries on Shrove Tuesday (the last day before Lent) but especially in New Orleans.
Bottleneck effect is when there's something that either kills the majority of the population or just prevents it from reproducing. This creates genetic drift because the likelihood of gene prominence changing is much higher in a small population. The Founder Effect is a type of Bottleneck effect. It is when a small amount of individuals starts a population usually due to migration.
A population BOTTLENECK may also cause a FOUNDER EFFECT, even though it is not strictly a new population. The essential difference between bottleneck and founder effects is that a bottleneck is a subpopulation caused when a natural disaster reduces the size of an original larger population, while a founder establishes a subpopulation as a new colony drawn from a larger population.