This is bird note.

By midsummer, many shrubs that in May shone boldly with flowers are now bearing fruit,

fruit that birds find irresistible. Elder berries, service berries, blackberries, dogwood

berries, bulberries, currants, and dozens of others.

Wax wings, tanagers, robins, gross beaks, even tiny warblers feast on nature's bounty.

We might think that plants are being generous by offering such a rich supply of nutritious fruits.

In truth, something other than largesse is at work here.

Plants evolved fruits as a kind of bribe, a way of enticing mobile creatures like birds to ingest their seeds.

Birds then excrete those seeds hours later as they move widely about the landscape.

Plants themselves take no metabolic benefit from the sweet pulp of their fruits.

Instead, they offer this bounty in exchange for birds' help in distributing their seedlings in new locations. Flowering plants also rely on winged animals for pollination.

And in dispersing pollen, birds, bats, and insects also help guarantee a new crop of berries.

Those brightly hued reminders of mutual benefit,

the co-evolution between plants and animals.

For bird note, I'm Mary McCann.