The answer is a lot. In a fairly scientific sampling study from my deck I watched a single Western Wood-Peewee calling incessantly - with the half-song notes - for several days. I went to my records and found that the bird had been calling for 30 days - for around 12 hours per day - almost non-stop at a rate of 7 calls per minute making approximately 150,000 calls during that time. It has now slowed to just intermittent calling of 2 to 3 hours a day, but still that many calls from one little guy is pretty impressive!
Rob

Rob Conway
Camas, WA
45.58?N 122.44?W - elevation 310 ft.
robin_birder at hotmail.com