If you are sure it is RFI (radio frequency interference) and not a range problem there are a few things you can try.

1. Distance

2. Shielding This may be hard, but if it wont make your motor get too hot, put 3 or 4 layers of aluminum foil around it. Be sure it is grounded. You can do this in most cases by keeping some portion of the aluminum foil in contact with the case of the motor.

3. The wires from the speed control to the motor will act as an antenna when a load is presented to them. In order to minimize this you need to set up a choke. Do this by using ferrite beads. You pass the wire through the center of the bead and rap it around 4 or 5 times.

4.Try another camera set up in a different frequency band. If your using 900MHz try 1.2Ghz… if you can find one, a 49MHz one would give you the best range with less power, but the antenna is long and you may end up with other interference problems.

I you have any amount of antenna or RF knowledge, you may consider building a directional yagi beam for the receiver and have a friend point the antenna at the bird while you fly.

I hope this gives you some help…

Good luck.