What is the mood of the poem "to a waterfowl"?the over all mood of the poem

Organized around the scenic images and the poet's somewhat whimsical reflections, "To a waterfowl" by William Cullen Bryant has a spiritual tone as the poet opens a dialogue between Nature and his soul:

There is a Power whose care/Teaches thy way along that pathless coast--

Certinly, these lines can hold true for man or fowl.  Like the bird that "the abyss of heaven/Hath swallowed up," the poet's soul, too, will be guided by the "Power," and have direction through his solitary journey through life.

The beautiful nature imagery of Bryant helps to create the connection of Nature with the spirit of the poet's soul.  The "marge of river wide" and "chafed ocean side" suggest that the paths of the bird are ambiguous and in need of one to guide him.  The auditory image of "scream" rather than "cry" or another word suggests the bird's exhiliration, an exhiliration to be compared to the soul's finding a path in its life journey.