At this time of year two birds seem to suddenly appear with the arrival of the plum blossoms.

Often confused, the 'uguisu' (鶯 'bush warbler') is the plainer of the two.
The small, bright green birds are called 'mejiro' (目白 'warbling white-eye').

Uguisu-mochi (うぐいす餅) is made by wrapping 'gyūhi' (求肥), a dough of kneaded rice flour and sugar, around bean paste.
The sweet was originally finished with a dusting of tea powder, but nowadays a green soy bean powder is used (or mugwort is added to the gyūhi).