Dem gegenüber steht:
Canuck. colloq. Also Kanuck, etc.
[App. f. the first syllable of Canada.]
A. n.
1. A Canadian; spec. a French Canadian.
[OED2]

Ca·nuck, n. Slang (sometimes offensive).
a Canadian, esp. a French Canadian.
[RH Webster's Unabridged]

http://www.angelfire.com/geek/APRACE/glossary.html
for one of the possible origins.

http://www.canuckabroad.com/
is a website created by a Canadian (without a French version, btw)
another one:
http://www.canuck.ws/?browse=/Regional/North_... (again without a French version)

the term is familiar to me from stories dating back to WWII, and refers generally to 'Canadian'. No reference was ever made in any of these stories to 'specially Franco-Canadian'.

googling for Canuck and Franco-Canadian gets 98 hits,
Canuck and French-Canadian gets 838 hits,
Canuck and Canadian gets 148,000 hits.

References to 'specially Franco-Canadian' appear to be circulating only in dictionaries. Usage in the field does not reflect this at all.

Fehlereinsendung is right, and supported

Don't know about the dictionary, but I have lived in both French and English Canada, but have never known it to mean French Canadian specifically, only Canadian.

Ich habe ueber die Jahre etliche kanadische Arbeitskollegen gehabt und kann von daher bestaetigen, dass "Canuck" eine Bezeichnung fuer alle Kanadier ist. Das Canadian Oxford Dictionary (bearbeitet von einem kanadischen Team) meint auch lapidar:

Canuck n. & adj. informal
n. a Canadian. adj. Canadian. [apparently from Canada]


Lighter's Historical Dictionary of American Slang unterscheidet wie folgt:

Canuck n. [perh. var. of kanaka 'South Sea Islander' (< Hawaiian), since both Freench-Canadians and such islanders were employed in the Pacific Northwest fur trade; later reanalyzed as Canadian + arbitrary suffix]
1. a French Canadian. -- sometimes used contemptuously.
1835 in DA: Jonathan distinguishes a Dutch or French Canadian, by the term Kanuk
1840 Ibid.
1881-1882 Howells Modern Instance 119: And Fridays I make up a sort of chowder for the Kanucks; they're Catholics, you know
1891 F&H II 23: Within the Canadian frontier ... a Canuck is understood to be a French Canadian
[...]
2. a Canadian; (hence) a Canadian vessel, animal, etc. also attrib.
1849 in OEDS I 429: Come boys and have some grog, I'm what you call a canuck
[..]
1871 Schele de Vere Americanisms 589: Canacks, Canucks, and even K'nucks, are slang terms by which the Canadians are known in the United States and among themselves.
[...]