how much drag does that camera add, kinda like drop tank huh...?
When they're filming, the birds aren't going "max" speed. They'll go plenty fast though, if you get them up and let them stoop. During lure flying, like in that video, they aren't going terribly fast. The birds often wear a small, lightweight "backpack" anyway, that the telemetry clips into. They take the telemetry off and replace it with the camera. The problem I've run into with my camera is that even at just .8oz, it flops left/right too much. My camera is an el-cheapo model though, and records onto a memory card. The camera from that video actually broadcasts, and they get a much better image.
You have to remember too, that the bird has to carry that camera load through the G's in its turns and at the bottom of its stoops. That adds up fast. The bird itself only weighs about 20-30oz depending on whether it's male or female.
When they really go for speed, they don't measure it with a camera, and you're right the drag would be detrimental. The only thing I've seen them attach to measure speed was the "guts" out of a skydivers dive watch (I don't remember what it's actually called). They use that to measure vertical descent rate, and it clips into a tailmount, which is another way to attach telemetry.
With the camera, beyond some really cool footage, they like to turn it to see how the tail is working to control flight, etc...
