The desire to travel does not wane with age, but the body’s ability to recover from it does. Turning 70 in 2025 was a milestone, one I chose to mark with a year of travel. Whether I had the stamina for it was another question. I’ve been traveling through Japan since I was 25, and now I wonder what has changed more — me or the country I have spent so long exploring. Birds have captivated me since childhood, and Japan has fascinated me since my 20s, so I set out on my yearlong journey focusing not on famous sights or geographic extremes but on Japan’s birds. In the 1980s, I introduced to Japan the idea of a “birdathon,” defined as 24 hours of nonstop birding. For 2025, I decided, perhaps rashly, to attempt the equivalent of a yearlong series of birdathons — a “big year” of birding. Traveling at 70, among what is often called the “silver set,” is a far cry from my travels in my 20s. Then, my energy and endurance seemed limitless; now they must be marshaled.…