鹅 can refer to quite a few birds in Chinese[0], and in this case, since the article noted:
Vancouver city council candidate Jean Swanson’s (金玉鹅) [has a] beautifully phonetic and semantic rendering of her name
鹅 is probably referring to 天鹅 ("swan")[1], which is part of Swanson's family name.
A bit of an explainer: In names, a word that's usually two characters long is often truncated. For example, the name of the kirin (麒麟) is often used in names, but is often truncated to 麟 (麒 is also possible) so that another character (e.g. a verb) can be introduced, e.g. Alan Tam's given name[2], 詠麟, means to rhapsodise about the kirin.
>Usually the more chars resembling wealth in your name, the less educated family you may be from.
Swanson's an anti-poverty activist,[3] so perhaps that may explain something about why 金玉 might have been appealing as a reference to 金玉滿堂.
Her party "has traditionally been associated with tenants, environmentalists, and the labour movement"[4], so I imagine that perhaps she wanted something green in the name as well, and jade (玉) fits the bill.
[0] https://en.wiktionary.org/wiki/%E9%B5%9D#Chinese
[1] https://en.wiktionary.org/wiki/%E5%A4%A9%E9%B5%9D#Chinese
[2] https://en.wikipedia.org/wiki/Alan_Tam
[3] https://en.wikipedia.org/wiki/Jean_Swanson
[4] https://en.wikipedia.org/wiki/Coalition_of_Progressive_Elect...
I've never heard of or seen this character until today.
>most people know of it as it's part of the idiom: 燕雀安知鸿鹄之志.
"Most people" usually mean "people around me", so it's not indicative.
There are plenty of ethnic Chinese people not living in China who might not have heard of this idiom -- in part because their knowledge of Chinese may not be as deep as people who've gone through the Chinese education system -- and one of them had probably advised Swanson on her name choice.
金 = gold/golden, 玉 = jade, 鹅 = goose
Usually the more chars resembling wealth in your name, the less educated family you may be from. Basically it just shows your eagerness to become rich. Not to mention the last character, which is rarely used char in names, who wants to name their child "goose"?
金 and 玉 are actually common in names, but usually combined with other good words like 诺(promise), 心(heart),... something like that. Decent names are not that straightforward and I think it may be the same in the western world.