Jealous? - perhaps release the tension by biting a lucky one’s butt.

Watching terns can never be boring.

After paying his dues with number of fishes, lucky Royal was in the act of exercising his marital rights when pair of Sandwich Tern landed near by; other SATE pair was already there just watching. One SATE got jealous, irritated by someone being more successful, so to rid off of its own frustration run to the mating ROYT pair and stubbed-bit moving Royal’s butt. Effect came right away - ROYT pair separate instantly. Although male ROYT did not look happy and SATE tried to stood its ground, no more aggressive actions happened. I do not recommend this kind of action to release the stress in the human world - most likely the consequences could be way more severe.

Interestingly I often see that many birds are getting agitated by watching other pairs mating.

And a tendency to look for a reason to who’s butt to kick (stub, bite; terns with their short legs would have a real problem with kick; in humans occurs from a child to a leader) seems to evolved a long time ago…