Tried to make it a bit better. Did not succeed.

Getting the shot in the field always makes it easier in the post edit dept.
I can't compare lenses other than my Canon75-300 that I use for a paper weight because of the poor quality. It's horrid! I've read mixed reviews on your lens and wonder if you have access to a high end lens. My 200mm is a gem, but cost gem price, Internal focus is super fast and well worth the additional dollars
Here's something else to look into for this type of shot Clew, servo focus.
If you don't already use it, check your focusing options of:Auto, Single, Continuous and choose Continuous. This will help track if you're not already using it. Many people try with Auto focus, but once it's locked on, your subject will fly out of focus.
Enjoy.

This is my first camera, so I just bought the lenses that I thought would go with it. I will research for an decent lens that I can afford. I am sure that I cannot afford the lens that you use but I do understand your point. Thanks so much for the info. I was using auto and was pretty frustrated at times when it would go out of focus within a shoot sequence. I will definitely try the continuous option. Your guidance is most appreciated.

Clew, there is a huge market opening up for aftermarket lenses and like always, I like Sigma. The link below will take you to a page with a Nikon /Sigma 400mm that has internal focus (important) and don't be afraid of the price, look into eBay before purchasing anything photo related.
[url]http://www.sigmaphoto.com/lenses/lenses_all_details.asp?id=3275&navigato...
I like your subject matter right now, but sadly must wait a month or more before these guys make it back my way on their northern trek.
Keep on snapping! Enjoy.

Thank you.