If the cuckoo, the swallow, and the nightjar be pre-eminently the birds of Summer (though, truly, the swift, the flycatcher, and the corncrake have as good a title) the rear-guard of Spring may be said to be the house-martin, the cushat, and the turtle. Even the delaying wheatear, or the still later butcher-bird may have come, and yet _Sweep-Sweep_ may not have been heard about the eaves of old houses or under and over the ruined clay of last year’s nests; the cushat’s voice may not have become habitual in the greening woods; and the tireless wings of the turtle may not have been seen clipping the invisible pathways between us and the horizons of the south. But, when these come, we know that Spring has traversed the whole country, and is now standing ankle-deep in thrift and moondaisies in the last rocky places fronting the north sea. No one doubts that summer is round the corner when the flycatcher hawks the happy hunting-grounds of the apple-blossom, when the swift wheels over the spire of the village church, and when the wild-dove is come again. The first call of the cuckoo unloosened the secret gates. We are across the frontier in that first gloaming when we hear “The clamour musical of culver wings Beating the soft air of the dewy dusk.” W. S. To these familiar and loved harbingers from the south should be added yet another welcome friend who comes to us in the rear-guard of the Spring, though, rather, we should say he becomes visible now, for the Bat has never crossed the seas. The house-martin has not had time to forget the sands of Africa before her wing has dusked the white pansies on the sunside of old redbrick English manors: but the bat has only to stretch his far stronger yet incalculably less enduring pinions and then loop through the dusk from ivied cave or tree-hollow or the sombre silences of old barns, ruined towers, or ancient belfries sheltered from rain and wind.