There are just a few things that compensate for being quite ancient: one is that (if you started birding early enough) you might have built up a decent list including species that could be unrepeatable. You may well have watched Clapton, The Stones and similar legends in their pomp. One of the most satisfying aspects of being 68, though, is seeing theories that were widely ignored (or even ridiculed) when you originally published them being generally accepted by the wider Scientific community.
An example from my personal output is exemplified by NASA's recently-published images of Pluto. Thanks entirely to our American colleagues, Pluto is currently classified as a minor planet or Kuiper Belt Object: to many of us it will always be the mysterious ninth planet. The image (see below) shows that Pluto, like every solid body in the Solar System, is pock-marked with craters of all sizes.
Until very recently it was axiomatic that craters on the Moon, Mars, Mercury and the various asteroids and satellites were the result of asteroid impacts. For years I've been virtually alone in questioning this: to me the absence of any meteoritic material in or near most of the Earth's impact craters suggests that the more likely impactors were comets. A few years back I had a book published that set out the evidence in great detail: it's available all over the net, but if you contact me directly, I'll send you one at a reduced price and even sign it!
Now Pluto orbits the Sun about six billion miles out: way beyond the regions in which asteroids are found. Out there in the Kuiper Belt, however, is an immense population of cometary nuclei: billions of them! For reasons still unclear, these occasionally tumble into the inner Solar System, where they might collide with the major planets. It must be inarguable that Pluto's craters were the result of cometary impacts: we can infer that the same is true of the other eight planets and the various other cratered bodies. To put it succinctly: the images of Pluto suggest very strongly that the dinosaurs, trilobites, megafauna and, nearly, the population of Chernobyl, were wiped out by comets rather than asteroids...
I await my incipient Nobel Prize, knighthood and honorary doctorate!