Kilgore Trout
Misanthropic Humanist
Well, as a Brit, this isn't something I'd know about.
If it happens every year as a natural event, as you imply, then there's nothing to it. But then why the article?
If it has only happened this year, then that is something of note.
Yes, herd animals often run or trot as a group, either as part of their migratory path, or just as a matter of course for any number of reasons.
Why the article? Because their are millions of hack writers, bloggers, and assorted whackjobs out there who need to justify their existence.