If a bird is at rest in a container and suddenly takes flight inside the container, will the weight of the container be reduced by the weight of the bird?

http://www.sciforums.com/showthread.php?t=66943&highlight=birds+truck

I gave this as a practice exam question to my students. Think: Newton's third law.

The weight will increase as the bird launches, then return to the original value as the bird flies around (with slight fluctuations from wind off the bird's wings).

Birds in a truck

*Snap* :)