Don't have a radar handy? Then point a telescope at the full moon as is rises in the east in late August or September and watch for the tiny specks flying acros

Don't have a radar handy? Then point a telescope at the full moon as is rises in the east in late August or September and watch for the tiny specks flying across the disk. On a typical night, you can see one bird every minute or so but on rare occasions they can number in the hundreds every few minutes. When you consider the arc of the sky you are covering the number of birds involved is staggering.