For an artist so well known, you would think Winsor McCay's birth date would be easy to establish. For American artists (on which subject I'm definitely not an expert) I usually make Wikipedia my first port of call. Here I learned that there was quite a bit of confusion about McCay and his origins.
"He claimed to have been born in Spring Lake, Michigan, in 1871, but his gravestone says 1869, and census reports state that he was born in Canada in 1867." Hmmm....
The New York Times obituary for McCay says he died (on 26 July 1934, which sources all seem to agree upon) at the age of 62. "Winsor Zenic McCay was born at Spring Lake, Mich., where his father was a lumberman." The implication is that he was born in 1871/72.
This is roughly what McCay said in census returns. The 1910 census finds him living in Brooklyn, aged 40 and said to be born in Michigan of Canadian parents. The 1920 census gives the same information, with McCay's age increased to 50.
However, working backwards, the 1900 census return gives his date of birth as September 1868. McCay (listed as Windsor McCay), is already married to Maude Lenore McCay (nee Dufour) and the two were living in Cincinnati, Ohio.
With no 1890 census data to check, we have to take a 20 year leap back to the next census return available. Here the McCay family are listed under their birth name of McKay and the five family members are living in Spring Lake, Ottawa County, Michigan. We can now introduce McCay's parents: Robert and Jeannette, both listed as 38-year-olds from Canada. Their children are Zenas W. McKay (12), Arthur (10) and Mary (4). Zenas was born in Canada and the other two in Michigan.
(* Since Mary isn't going to be mentioned again, IGI records show that she was born Mary C. McKay at Spring Lake on 21 May 1876. Neither of her siblings are listed.)
Continuing our trip backwards to 1870, Robert (29) and Jennie (28) are already in Spring Lake, with sons Zenas (3) and Arthur (2). Again, Arthur is the only child born in Michigan.
As you'll have seen from the above, Winsor McCay's age changes over the years. The 1870 census was taken on 16 August 1870 and his age as of his last birthday was 3. This implies that he was born between 17 August 1866 and 16 August 1867 and, if we are to believe he was born in September that would have to be September 1866. The 1880 census returns were made on 2 June 1880 and 12 years of age implies a birth between 3 June 1867 and 2 June 1868, or September 1867. By 1900 he was claiming to have been born in September 1868.
So why all the changes of dates?
One explanation can be spied if you work the information from the other direction. A bit of good fortune means that a little searching reveals that Robert McKay, the son of Donald and Christiana McKay, was living in West Zorra Township, Oxford, Ontario, Canada, when he married Janett Murrey, daughter of Peter and Mary Murrey, on 8 January 1866. Robert was aged 23 and his new wife 25. In the 1870 census they give their ages as 29 and 28, and 38 and 38 in 1880. I don't know if social convention frowned upon a man marrying an older woman but the slippage of two years by Jannett/Jeanette McKay may explain why their sons also managed to lose a year or two in the same period.
And, should Zenas Winsor McKay have been born on 26 September 1866, that was only 7 weeks after his parents married.
So take your pick... 1866 or 1867 are both likely. But probably not 1868 or 1869 and definitely not 1871.
A sad note regards McKay's brother Arthur. In 1900, as Arthur McCay, aged 31, he is an inmate of North Michigan Asylum, Grand Traverse, Michigan. He is still an inmate in 1930 (in the latter two decades the institution has been renamed Traverse City State Hospital), the last US census currently available.
Zenas Winsor McCay was reputedly named after his father's employer Zenas G. Winsor, about whom there is plenty known as he was well covered in the book American Biographical History of Eminent and Self-Made Men with Portrait Illustrations on Steel: Michigan Volume (Cincinnati, Western Biographical Publishing Company, 1878), pp.134-35.
Winsor's post-1868 biography isn't quite so well covered but the Pioneer Society of Michegan papers for 1891 notes Winsor's death at Chattanooga, Tennessee, on 3 August 1890. He and his wife were visiting their daughter, Mrs. George W. Wheeland and her family. He had not been well for some time, but his immediate cause of death was typhoid fever.