This is actually a proverbial saying.This proverb literally means that when there are many birds vying with each other to catch a single worm,the birth that arrives early has the best chance of catching the worm.Similarly in life a person must be well ahead of others in terms of effort and preparation,one must also plan well in advance and grab at chances before others arrive because one who arrives first get the best chance for success.Only this way can success be yours.