Caught this little guy by himself for a few seconds. The histogram looked fine but I'm worried the whites are still blown, although it is a white bird in full sun, so I'm not sure bringing out any detail in the brightest whites (if there is any there at all) would have done anything other than underexpose the rest of the bird. This is also the second time I've noticed my pictures having a gray cast when using a teleconverter. I tried to get rid of it with adjustments in ACR, but I'm not sure why it keeps showing up. Almost like you're looking at the picture through a neutral density filter.
Have at it!