Bird song is among the most conspicuous natural phenomena of May. If you have recently walked at the Ames Free Library or, for that matter, anywhere in southeastern Massachusetts, you couldn’t help but hear the chorus: resident birds, newly-arrived migrants, and passers-through are all singing. Those who stay sing to attract mates and to announce their territory. In most, though not all species, the males deliver the songs. They sing like there’s no tomorrow and, indeed, there really isn’t. Our short-lived songbirds must start the process of raising young while food is avail