Here's a little insight..... I fish a lot... In the past, some commercial. This last Fall was up to 55 miles off of Washington's coast in a 17 foot boat chasing albacore tuna for me. Birds are NO problem to catch when you have fishing gear that imitates bait fish.... plugs, lures, bits of fish would make it very easy to catch birds with hooks and line. NONE! No problem... Birds are a nuisance while fishing for tuna. This guy, if I understand the story correctly, is a commercial fisherman from his country. Central or South America somewhere. His boat looked like crap but that is how it is in some countries. I have no doubt he would have enough food, he was equipped to catch fish and easily could catch birds. It's the potable water that is my only question..... Did he have enough? Destillers are not hard to make, I could make one with plastic, a bucket, a cup and string.... just off the top of my head... the cup could even be made with plastic...
On this story of survival at sea... I believe.... There are accounts of survival that go way back...