April 30, 1951: Pennies went farther then

Patty wears a travelling coat in this one, a decidedly 50s-ish touch.

This is the start of a minor running gag, the Peanuts kids often get candy or comics from this particular drug store, and the manager gets annoyed when they don't buy things. (Just think: Peanuts started back in the days when drug stores were still a suitable kid hang-out spot, and ended in the days of the Internet!)

May 2, 1951: Snoopy likes bananas

This is not actually the first Snoopy-hears-food strip.  In the first, Charlie Brown was eating an ice cream cone.  It's another running gag.

April 27, 1951: First use of a blush

Is it just me, or does Snoopy's tongue being stuck out in the third frame seem a little like it's over-stating his attitude? Schulz usually leaves more to the reader's imagination.  But anyway, it's the first doghouse, or birdhouse I suppose, seen in the strip, so it's worthy of commemoration.  It also marks the first time a character blushes to show embarassment.

April 26, 1951: Strength in numbers

A decidedly Lucy-like maneuver.  Patty and Violet seem to get more cruel when they are together.

April 25, 1951: As a kid, this is what I thought golf was

The first use that I've noticed in Peanuts of thick, outlined letters, here in a word balloon.

Notice that Charlie Brown's shirt is missing its stripe in the second panel, probably because it wouldn't read well with his arms and club in the way.

April 21, 1951: Frieda would love this

Good poses for Snoopy here. Shermy's apology to an annoyed Snoopy is a nice touch.

April 20, 1951: Team sponsorship

The mud pie strips have been leading up to this, which wouldn't have been as funny without them. It's not the last one, though.

But this strip is notable because it's the first in which Charlie Brown plays baseball!

April 19, 1951: A dog without gravity

Later on, Snoopy would lose his ability to experience, or express, this kind of enthusiasm, although he'd pick up other means. But we do get another three-quarter perspective leap out of him while he's still capable of it.

April 17, 1951: The bird's a solo act

No thought balloons yet, but Snoopy's dealings with a decidedly non-Woodstock bird are looking more human.  Something to notice: when Snoopy's head is facing the "camera" in three-quarters perspective, his eyes are a little closer together than in previous strips. Earlier he looked almost fish-eyed, but they've begun to migrate to the front.  Over time, all the characters' eyes would move closer together, which helped to give them a more mature appearance as the situations became more complex.

April 16, 1951: Snoopy chases bird down stairs

That bird is back, and so is the scribble of ire.

Eventually, it's either this bird or one that looks a lot like it that builds a nest on Snoopy's stomach while he lies atop his birdhouse EDIT: dammit doghouse, and it's one of the birds to be born from that nest who would become Woodstock.

Woodstock would pine, around Mother's Day every year, for his mother. Schulz and Peanuts: A Biography notes that Charles Schulz's mother was rather cruelly taken from him within a week of his going overseas to fight in World War II (her funeral was the day before he shipped out), a blow it seems he never recovered from.

But anyway, it's weird to think that the unobtainable love and affection that Woodstock sought from his absent mother all those years may be right here, in this very bird.