Read the passage and then answer the question that follows:
The European Starling is no larger than the average bird. Despite its normal size, it is surprisingly harmful to farmers. The massive size of flocks (up to 750,000 at a time) is well documented. On several occasions, it has been known to destroy entire crops. All things considered, it may just be one of the most destructive species in the sky and on land.
In the passage, which transition is used to summarize an idea?
All things considered
Is well documented
On several occasions
Surprisingly