Bizarre Tawny owl activities Nr Cliffe Pools

Hello. My partner & I are both mudlarkers, walkers, & amateur birdwatchers who regularly take a stroll around the fantastic reserve and the nearby Thames estuary. Last Friday 21st Feb in a more remote part of the estuary between Egypt Bay and St.Mary's Bay, we were amazed to see three Tawny Owls in broad daylight perching on an old pier support. Delightful as it was to observe them through binoculars in the sunshine, what happened next was what brings me write this post. The tide was on the way in, there were waders galore bobbing & darting around. The owls took off and approached a group of waders from two different directions, one "spooked" the flock causing them to take off whilst the others came swooping in to hunt them as they left the water or the mud. This was repeated time and again,it was absolutely fascinating to watch.There is no doubt that they were acting in concert. The Owls were regularly mobbed by a half dozen or more Gulls, at times it resembled the type of dogfight that took place here 70 years ago! The number of times that one of them nearly landed "in the drink" whilst being mobbed made for a lip biting spectacle, but all three of them made it. Their actions seemed foolhardy to the point of desperation. Given that the surrounding fields are all but submerged it made us think that perhaps their natural prey has disappeared and for them to hunt like this in daylight, over water, must surely be aberrant. I hasten to add that during the time we observed them they were wholly un-successful in their attempts. Is this unusual behaviour?