Definition of "jonque"

I know not, indeed, if the artist could give the beautiful orange which distinguish [sic] the jonque, or the mellowness of tint that pervades the mealy.

1800, The New and Complete Canary-bird Fancier, page 8

Canary-birds, however, are not likely to become extinct; […] each flock is said to have its own peculiar song, but we must not think the "jonques," so popular among us, form the majority in a flock.

1865, All the Year Round, volumes 13-14, page 85

Pied birds are produced by matching a green jonque with a clean jonque, or a mealy hen.

1875, The Bird-Keeper's Guide and Companion, page 19