There’s a way, but it’s not easy, and also not 100% accurate.
If the tasks you need to get these informations are still in that section, first, query all ids of tasks in that section:
/sections/xxx/tasks
If you have too many tasks, I suggest to use the “search” endpoint with modified_since parameter.
Then, for each task, get their stories: (you can use the “batch” endpoint)
/tasks/yyy/stories
The opt_fields that you want are resource_subtype and created_at.
Then, loop all results, and find the most recent “resource_subtype” = “section_changed”.
But, watch out for this:
If a task was moved from another section to that section, you will see the “section_changed” event.
BUT, if the task was created directly in that section (or moved from another project?), that event does not exists.
You will need to see the most recent “added_to_project” instead.
Important note: in asana, you can “delete” items from history!!! Stories are editable and deletable. It’s possible that none of the stories are available if someone deleted them.
There’s more informations available about stories “resource_subtype” on that thread.
Hope this helps!