HI!
First of all - I'd like to thank you for reaching us and showing your expectations as to the behaviour of the application 
For some time already we have been reviewing, rethinking and (re)working on Jira Software, focusing on transparency of user actions, user supervision && data visibility. While scanning through all the feedback we received related to those areas I have found your request and believe I have few, hopefully good, pieces of information that could be of a hand for you.
When thinking about sprint creation per se - there is very little information connected with the fact WHOM actually created the sprint.
Sprint - on creation - is a de facto empty container with a "random"pre-defined name.
Could you elaborate on what kind of information would you be looking for here? What would be the questions you'd like to get the answers for and how would they influence your work?
To be honest - keeping in mind that multiple users can create, re-arrange and delete multiple sprints just to fine-tune their (future) roadmap - I struggle to find any value in the information requested. But I'm guessing I just miss some information here.
When it comes to getting to know who started or reopened the sprint - this information is not directly displayed anywhere in the system… yet.
But we realise it is crucial for the team members to be aware of what's going on with the sprint - who (and when) starts or re-opens one, hence it directly impacts their workflow. Therefore - we will add this information to the system.
Moreover - the updates are already developed and are currently undergoing extensive tests. We also want to make them available as soon as possible - hopefully with next Jira Software Server release.
For consistency and better readability of the information you will be able to find them in a similar way as the (already available) information about "who closed sprint" action.
We realise it might not be that obvious to find it - therefore we created a dedicated KB article that explains in details all the ways one can obtain such information.
The knowledge base article can be found here: https://confluence.atlassian.com/jirakb/checking-who-closed-a-sprint-947165301.html
Once we release the update extending the info about sprint start and re-open action - we'll also update the KB mentioned above so that you can find all the relevant guidance in one, simple article.
I hope these changes will help you to better understand what goes on within your teams!
Best regards,
Michal
Sr. dev @ Jira Server TEAM
Since Jira contains the AO_60DB71_AUDITENTRY table in the database where the OPEN and CLOSE operations are already stored, it can't be rocket science to track the creation an changes as well.
Since the deletion of sprints is already saved in the System AUDIT LOG, it would be particularly nice if the creation or modification could also be found there.
But I'm afraid since both the reporter and the assignee of this task are inactive, the sugesstion goes to Santa Claus