Let’s say we each attract 5 breeding pairs of Purple Martins, which fledge a total of 15 young, on average, each year. At the end of 10 breeding seasons how many fledgling martins has our colony site added to the world’s martin population? The answer is 150. Pretty good, but when you consider that only about 35% of those 150 fledglings (or about 53 birds) live to see their first breeding season, our decade of effort is far less impressive.

But look at what happens to fledgling numbers if we each make it a standard part of our annual martin routine to mentor along one new landlord hobbyist who in turn fledges 15 young annually. At the end of 10 years, instead of just 150 fledglings, we and our 10 mentees would have been responsible for fledgling a staggering 1500 martins! But it gets even better. If each of our mentees in turn becomes a mentor the following season, we get into the mathematical realm of chain letters and pyramid schemes, and the number of fledglings at the end of 10 years becomes astronomical.