No sooner does the frost leave the ground, than the moles begin to work close to the surface, making ridges where the earth is soft, and throwing out small mounds, when it is packed firm. The star-nose mole inhabits damp soil, while the common mole likes the dry highlands. Although moles' eyes are small, he who thinks that they cannot see, should hold his finger before one's nose and see how quickly it will be bitten. May Third The marsh marigold, which grows in thick clusters in the swamps and along the streams, is now in full bloom. These flowers are often sold on the streets for "cowslips," a name wholly incorrect. The leaves make fine greens. [Illustration: CHIMNEY SWIFT.] Notes May Fourth By this time one of your bird houses should be tenanted by a pair of house wrens. They migrate at night and the male arrives about a week in advance of his mate. Both birds assist in building the nest and in raising the young. As soon as the first brood has been reared, the lining of the nest is removed, and a new one built before the second set of six eggs is laid. Wrens may easily be tamed to take spiders and caterpillars (not the hairy ones) from the end of a stick and even from one's hand. May Fifth How much easier would be the work of nest building if we provided the birds with nesting material. Scatter strips of cloth, and pieces of coarse twine on the ground for the robins; hair from the tail and mane of horses for the chipping sparrows and wrens; twine and horse-hair for the orioles; bits of "waste" for the yellow warblers, and grapevine bark for the catbirds. None of these strands should be more than four inches long. May Sixth In some localities the shad-tree is now in full blossom. As you pause to cut off a few twigs, your ears are greeted by a never ceasing chorus of toad music. This is the toad's "love song"--a high-pitched, somewhat tremulous, and rather monotonous note. [Illustration: Photograph by J. Alden Loring. ONE OF TOUR BIRD-HOUSES SHOULD BE TENANTED BY A WREN.] Notes May Seventh Perched upon a stump, fence post, or low limb of a tree, the Bob-white sends forth his clear, far-reaching whistle "_Bob-white_." In the North this bird is known to every boy as Bob-white, or quail, while in the South he is called "partridge." The last two names are misnomers, for we have no native quails or partridges in this country. May Eighth The fronds of the sensitive fern resemble somewhat the leaves of the oak-tree, and in some localities it is called the oak-leaf fern. It is found in damp, shady spots, and is one of the common ferns of New England. The delicate, light green leaves wither soon after being picked, and it is the first of the ferns to fall under the touch of Jack Frost. May Ninth