The Collaborative International Dictionary
Sea canary
Sea canary \Sea" ca*na"ry\ [So called from a whistling sound which it makes.] (Zo["o]l.) The beluga, or white whale.
Wiktionary
sea canary
n. The beluga, or white whale.
Usage examples of "sea canary".
But whalers could have enlightened them in this respect, for they knew that whales possessed acute hearing, the constant 'twittering' of the White whale even earning it the name of the sea canary.