gendered playground behavior in preschoolers

One thing I hear a lot is "well, I didn't want to believe there were differences between boys and girls, but once I had kids, it was just so obvious". I had the chance today to watch Junie's preschool class at the playground (it's not a school day for her, but they were taking a little field trip and we were able to join them, and then they hit the playground after) and I thought I'd try to start looking for these obvious differences. No formal scoring, just rough mental tallying. Approximately 25 kids. What I observed: most of the activity could be divided into five types of play: running, climbing, swinging, digging, and banging with shovels. Running, climbing, and digging all seemed to be approximately gender-neutral. Climbing was the most popular activity, followed by digging. Swinging was heavily female, with girls swinging higher, more wildly, for longer. Banging with shovels, that I saw, was only done by boys; all the girl shovel-activity was localized to the sandbox and seemed to involve actual sand.

So, today's conclusion: while the most popular playground activities are gender-neutral, boys and girls do differ in their secondary choices, with girls showing greater interest in whole-body physical activity (swinging) and boys showing greater interest in making noise. Hypothesis: going down slides is also girl-dominated. (There wasn't enough slide activity at the playground today to count.)