The lapse of two centuries from the time of Chaucer witnessed a change in the mood of English poetry in regard to its treatment of birds. The simple and unaffected joy in the voices of the grove, so conspicuous in the poems of the author of the _Canterbury Tales_, had not become less, but it had been accompanied by the growth of a more observant and contemplative spirit. While bird-music was as much appreciated as ever, a much wider field of interest in the feathered tribes had been entered upon. Greater familiarity with bird-life had been attained, and much more was known about the habits of birds. Of this knowledge use was made by way of simile and illustration in regard to human life. How often and how vividly, for instance, does Shakespeare, by means of an analogy from the world of birds, portray the depth of man’s feelings,――his joy, his sorrow and his suffering! [Sidenote: _Birds in later Poetry_] The law of evolution, which has been so supreme in the history of organised life on the globe, does not leave the human mind outside of its influence. If there was proof of progress in poetic insight between the days of Chaucer and those of Shakespeare, we may expect to find on examination that other two centuries did not pass without leaving some evidence of change in the tone of our poetry. To test this inference, some typical examples may be taken from the poetry of the nineteenth century where it deals with birds, for comparison with the quotations which have been cited from our great dramatist. The subject is obviously far too wide to be fully entered upon here; but it may be briefly illustrated by selecting three well-known poems by three of the most illustrious of the English poets of the nineteenth century――the “Ode to the Cuckoo” of Wordsworth, the “Ode to the Nightingale” of Keats, and the “Ode to the Skylark” of Shelley.