Silverly

One June evening, when the orchards were pink blossomed again, when the frogs were singing silverly sweet in the marshes about the head of the Lake of Shining Waters, and the air was full of the savor of clover fields and balsamic fir woods, Anne was sitting by her gable window.

Source: tatoeba (5831749)

"This river does not see the naked sky, Till it begins to progress silverly Around the western border of the wood, Whence, from a certain spot, its winding flood Seems at the distance like a crescent moon: And in that nook, the very pride of June, Had I been used to pass my weary eves; The rather for the sun unwilling leaves So dear a picture of his sovereign power, And I could witness his most kingly hour, When he doth lighten up the golden reins, And paces leisurely down amber plains His snorting four.

Source: wiktionary

And when night comes, his spirits with chill feet, Winged with white mirth and noiseless mockery, Across men's pallid windows peer and fleet, And smiling silverly Draw with mute fingers on the frosted glass Quaint fairy shapes of iced witcheries, Pale flowers and glinting ferns and frigid trees And meads of mystic grass, Graven in many an austere phantasy.

Source: wiktionary

There was a tiny wren singing among the Balm-o'-Gilead trees on the opposite shore, with a voice that rose silverly above the noise of the rapids.

Source: wiktionary