A drop release that could be remotely tripped to release the bait once on station would be best. you migh try something up on the camera gimbal or using the leds on the arms. wouldn't use skip knot. knots are notorious for failing either breaking or, worst in your case, not coming untied when you wanted them to. Try something like what sportfishermen use when they us a kite to carry their bait out. A simple spring loaded clothespin holding a tab attached to the line would release quickly when a fish pulled on the bait. Spring tension can be adjusted by trial and error to make it strong enough not to pull out just from the weight of the line and bait but weak enough to let go when you get a bite. But, I'm sure that yo realize that anything like this attached to the bird will greatly risk the chances of it going into the water!