Of Men and Rats and two postscripts
When John Blakeman acknowledged that "It's becoming clear that rats are the missing prey, substituting for the voles of rural areas," I replied:
Well, it makes sense. Rats are extremely clever animals, it seems to me, and there's a great deal of human food consumption that goes on in the park on a large scale during daylight hours only. People purchase hot dogs and pretzels from the numerous [year-round] vendor carts, leaving crumbs and more behind. Another factor, I'm sure, are the various bird and animal lovers in and around the park who deliberately feed critters -- People bringing sacks of grain for pigeons every day, [the redtails know these regular feeding spots and perch nearby], all the squirrel feeders who feed their bushy-tailed friends almonds and walnuts as well as peanuts daily. I'm afraid the Bird Feeding squad [I'm on it] that fills feeders for the various titmice, woodpeckers, sparrows, etc. once or twice a week in the fall and winter may contribute to the rat feast as well.