Every now and then we ask where a certain association of Brigit's arises from. Recently it was the swan. Here is one answer, from Carmina Gadelica, Vol. 1, edited by Alexander Carmichael, in Scottish Gaelic first, and then in English.
Eala bhan a ghlugaid bhinn,
Odhra sgaireach nan ciabh donn,
Cha ghear thu it as an druim,
Gu la-bhrath, air bharr nan tonn.
Air an ite bitheadh iad a ghnath
Mu 'n cuir thu lamhaidh ri do chluais,
Is bheir Moire mhin-gheal dhut dha gradh,
Is bheir Bride aluinn dhut dha buar.
Chan ith thu farasg no blianach,
No aon ian nach leag do lamh,
Bi-sa taingeil leis an aon-fhear,
Ge do robh a naodh air snamh.
Eala shith Bhride nan ni,
Lacha shith Mhoire na sith.
The white swan of the sweet gurgle,
The speckled dun of the brown tuft,
Thou shalt not cut a feather from their backs,
Till the doom-day, on the crest of the wave.
On the wing be they always
Ere thou place missile to thine ear,
And the fair Mary will give thee of her love,
And the lovely Bride will give thee of her trine.
Thou shalt not eat fallen fish nor fallen
flesh,
Nor one bird that thy hand shall not bring down,
Be thou thankful for the one,
Though nine should be swimming.
The fairy swan of Bride of flocks,
The fairy duck of Mary of peace.