From that article: "In other words, the birds tell each other about a dead companion, and so individually and collectively the scrub-jays may learn something about predation risks. By calling in others (the cacophonous aggregations), they may be more likely to drive a predator away or to warn relatives and mates of danger." - Barbara J. King
This may tell us something about how trout evolve to be more selective - they learn that eating certain "food" can cause them to be pulled to shore, and general leeriness of suspect food becomes the m.o. Maybe they then can share what they've learned to be "hook-ful food" with others, and eventually they collectively (and slowly) learn to identify a Stimulator or Girdle Bug as a no-no, at least now and then.
Or maybe trout are just instinctual animals that cannot help but eat what appears to be food.
|"AAAAHHHHH!", the trout said.|