Eastern Bluebirds: video of pair

The video above shows first the male then the female Eastern Bluebirds fly to the nest cavity to feed their nestlings then 'fecal sacs' to keep the nest clean. I thought the color of the bird's feathers was brilliant in the video clip when the sunlight hit them. Above photo shows the male with it's head inside the cavity--he continues to be very task oriented: he flies in and quickly delivers the food to the nestlings and take the fecal sac, rarely bothering to look in my direction. The female shows less concern about my presence but still looks over at me, and at surrounding area, several times while at the nest.

 I take my photos from inside my car and my videos using a tripod right next to the car door so I can use my car as a 'blind', a technique I use frequently as it disturbs birds less and provides better photos and videos. I stay more than 30 feet away then use a very long telephoto set-up (close to 900 mm equivalent) to get these close-ups.   I try to avoid interfering with birds as they go about their daily tasks and especially nesting birds--I think this is the ethical thing to do  and I believe it also results in  better photos when birds are not distressed by your presence. 
 SeEtta