Definition of "blithesome"

Fare not the birds well, as from spray to spray / Blithsome they bound—yet find their simple food / Scattered abundantly?

1794, Robert Southey, Wat Tyler. A Dramatic Poem. In Three Acts, London: […] [J. M‘Creery] for Sherwood, Neely, and Jones, […], published 1817, Act I, page 9

She made herself as blithesome as a lark, and at last she offered him two hundred dollars if he would sell her the whistle, and tell her how she should manage to get it safe home with her.

1886, Peter Christen Asbjørnsen, translated by H.L. Brækstad, Folk and Fairy Tales, page 175

[']Take the Adventure, heed the call, now ere the irrevocable moment passes!' 'Tis but a banging of the door behind you, a blithesome step forward, and you are out of the old life and into the new!

1908 October, Kenneth Grahame, “Wayfarers All”, in The Wind in the Willows, New York, N.Y.: Charles Scribner’s Sons, page 211