These large birds are really magnificent in flight and a little easier for the 50D to capture than the all white egrets.

The 500/4 and the 50D works very well together. This is now my favorite BIF setup. The 1DmkIII and the bare 500 is a little short and I need to add the 1.4 extender, which makes the AF slower. The extra MP of the 50D is also great capturing more details than the 1DmkIII. However the dynamic range of the 1DmkIII is better and the 50D blows the whites easier.