Is it possible that Beatrix has been having trouble catching birds, so she has resorted to catching the Giant Water Beetles for food? 
No, if she had problems catching birds she wouldn't still be alive, the peregrines need a lot of fuel, can only go a couple of days without food before dehydration starts to kick in, another day or two before their systems start feel the lack of food. She's made it through two full years, four migrations and she looks great and she wouldn't have been able to do all that if her hunting skills weren't good. In fact, the fact that she can catch Giant Water Bugs (they are bugs, not beetles) on the wing is a pretty good demonstration of how good her hunting skills are - granted they aren't speedy flyers but they aren't big either. When I've been on the road at this time of the year, I've found them dead on sidewalks in towns in southern Manitoba, but I don't know anything about their lifecycle so maybe this is the time they start flying looking for
and the opportunity for slow, small protein packs was just too good for her to miss. Back in the early 1990s, we had lots of grasshoppers and I watched fledgling chicks hunt them like crazy around their hack site, so insects are not new menu items, just more opportunistic menu items for those who want to take advantage of them.
