INTRODUCTORY. I I

Longfellow says :

“Birds of passage sailed through the leaden air from the ice- hound,

Desolate northern bays to the shores of the tropical islands. ”

Tennyson calls them,

“ \Vild~ birds that change Their season in the night, and wail their way From cloud to cloud.”

Our birds move southward on the approach of autumn. Some, like the swallows and the male warblers, retreat when summer has just passed its climax; others tarry till the snows and frosts of winter compel their departure. Some, like the robin and sparrows, merely go to the Northern 01' Middle States; while others, as the swallows, the redstart, and some other warblers, find a winter home on the sunny shores of the Mexican Gulf, or even in South America. 'l‘heir line of migra- tion is down the Atlantic coast. 'l‘hey cross the Gulf of Mexico by passing from Florida to Cuba, and thence to Yucatan.

Some of our birds, as the sparrows, thrushes, and warblers, move leisurely in their migrations,

feedingr their way from post to post, and occupy