Christina Rossetti - A Bird Song lyrics

It's a year almost that I have not seen her: Oh, last summer green things were greener, Brambles fewer, the blue sky bluer. It's surely summer, for there's a swallow: Come one swallow, his mate will follow, The bird race quicken and wheel and thicken. Oh happy swallow whose mate will follow O'er height, o'er hollow! I'd be a swallow, To build this weather one nest together.