"I know a bank whereon the wild thyme blows,
Where oxlips and the nodding violet grows,
Quite over-canopied with luscious woodbine,
With sweet musk-roses, and with eglantine:
There sleeps Titania some time of the night,
Lull’d in these flowers with dances and delight
-A Midsummer-Night’s Dream (2.1.260-5)
Or at least that is what I have tentatively identified it as. It and the pine warbler are not regular visitors to the feeder under usual circumstances, but what with the snow recently, these two are seen somewhat regularly!