These clips show some interesting interaction between the adult and nestling(s). The YouTube video description lists some of the high points. Watch for tongue action by the adult along the top of the nestling's head. 
There are what appear to be some deliberate pushes by the adult. Is she trying to encourage the nestling to leave? 
Some small flying insects appear to be of some concern to the nestling.  
The clips with the single nestling do not show the intensity of the feedings that the earlier clips show. Is this because of a lack of competition or is she feeding more nectar and less protein in preparation for fledging? Maybe it is easier to regurgitate nectar than insects. Some of the clips are longer than I would like, but I think that this is extremely interesting.

6:05 min.; 2012/08/31 Hummingbird nest near Big Walnut Bike Trail, Gahanna, OH http://www.youtube.com/watch?v=vJ-8P-IbPn4&feature=share&list=UU4Rh6oSk9g-OLtZLYXqCRzQ

8:15 min.; 2012/09/03 Hummingbird nest near Big Walnut Bike Trail, Gahanna, OH    http://www.youtube.com/watch?v=rD15PRvWZLE&feature=share&list=UU4Rh6oSk9g-OLtZLYXqCRzQ

8:23 min. 2012/09/04 Hummingbird nest near Big Walnut Bike Trail, Gahanna, OH   http://youtu.be/LMY4PMew1ms

There is one more clip, recorded 09/05, to be posted.

Regards,
Tom

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