Various sources will tell you that the April 4, 1967 strip was the first appearance of Woodstock in Peanuts. I’m here to tell you, that ain’t accurate. Yes, there was a bird who came to visit Snoopy on that date, unnamed at the time (as was every Woodstock appearance until 1970), but that bird had been seen before.
That this isn’t the first time that this bird met Snoopy is suggested by the very next day’s strip, where Snoopy refers to the bird doing something “every year”, suggesting he knows the bird’s patterns. So where have we seen that bird?
Back on March 4, 1966, two baby birds are born in a nest that had been built on Snoopy’s stomach. These birds are the first of the tossle-head birds in the strip, looking quite different from the more bird-like birds Snoopy would sometimes harass or be harassed by earlier on. The hatchlings are there for several days, flying away on the ninth. On the eleventh, they fly back – and note the flight patterns, the awkward, stumbling path indicated by a dotted line that would be the standard for Woodstock. They are gone again the next day.
On March 17, one bird returns. (We know it’s one of the two birds, because Snoopy says it’s “the return of the native,” and it’s unlikely that any other birds were native to Snoopy’s doghouse. Of course, the phrase Snoopy uses is a reference to the Thomas Hardy novel of the same name.) He flies in with the weak flutter and loop-de-loop we have come to know, and flies out in much the same way on March 19.
I’m not sure where the claim that the 1967 appearance was the first originated, but anything we have to identify Woodstock by – comfort with Snoopy (both the ’66 and ’67 birds fall asleep on Snoopy’s head), appearance, flight pattern – these are the same bird, and thus one of the two birds born atop Snoopy.
And that’s kinda cool. I mean to be there the moment when your best friend was born? Sure, the bonding was awkward at times, but it began right away. As the birds’ mother left before they were born, Snoopy was in a way the only parent figure they knew (and, by the way, the absence of the mother fits in well with Woodstock’s later searching for her.)
Woodstock: born to be Snoopy’s best friend.
Side note: Schulz would say that he had assumed Woodstock was a female until he picked the name Woodstock – but in both 1966 and 1967, Snoopy is using male terms like “he” and “guy” for the birds in question.