Here's a few numbers, hastily cut-and-pasted and not doublechecked. No warranty expressed or implied. Your mileage may vary. All incentives to dealer. If your spreadsheet lasts more than four hours contact your doctor.
So far during 2004 there have been 244,242 holes played on the PGA Tour. Of those 54,846 (22.5%) are Par 3's 143,906 (58.9%) are Par 4's and 45,490 (18.6%) are Par 5's. There have been 46,895 birdies recorded, about one every five holes. I'm not sure whether eagles are counted as birdies for this purpose but I suspect they are. Of those birdies 7,038 (15.0%) are on Par 3's 22,401 (47.8%) are on Par 4's and 17,456 (37.2%) are on Par 5's. Looking at it the other way, 13% of Par 3 holes were birdied 16% of Par 4 holes were birdied and a cool 38% of Par 5 holes were birdied.
So to answer the question at hand, the Tour on average makes 38% of its birdies on Par 5's. Tiger makes 41%, Vijay makes 38%, Ernie makes 40% and Phil makes 39% of their birdies on Par 5's. Nothing really interesting here folks, move along.
Note bene: I simply computed number of birdies for the Tour divided by number of holes for the Tour of each type. These are not averages of per-player averages but grand averages.