We stood on our front porch counting birds last Fourth of July. In the dawn’s early light, my son Dave timed me while I named the birds I heard or saw in three minutes–wood thrush, American goldfinch, indigo bunting, American crow, common yellowthroat, Carolina wren, yellow-billed cuckoo, chipping sparrow, blue-gray gnatcatcher, field sparrow, white-breasted nuthatch,…