Thrice welcome, darling of the spring!
Even yet thou art to me
No bird, but an invisible thing,
A voice, a mystery.
Source: To the Cuckoo.
-- William Wordsworth, (Apr 7 1770-1850), English poet; His Lyrical Ballads, 1798 are noted for their worship of nature and humanitarianism; poet laureate, 1843-50.