Denigration of motherhood. Was this program already playing in (post 1963) gradeschool? Simply asking, because

of a nature film us fourth-graders were watching.  Owls, i think, but whatever, mamma-bird and her four or live little-ones were living inside a hollowed out portion of a tree, and mamma was fixing to move house.  i specifically recall, that leaving the hollowed out enclosure required exertion  and coordination.  The youngsters had to, like jump up - there went youngin #1, #2, ...

Then came the last one.  He or she couldn't make the jump-up.  Mom and sibs hung around outside for, maybe a half minute, if that.  Then they took off.  i remember the camera focused on that - now left behind - little bird, still trying to get out.  And i remember, the darwinist sermon being proclaimed by the narrator - not the specific words.

What i do clearly remember, was being upset by the program.  No, i didn't cry, but was greatly bothered by it - that was over a 1/2 century ago, and the image of that little abandoned bird is still in my memory.  Tell me i was the only kid in that classroom who was bummed out at seeing that poor little bird left to die, alone and frightened!

Question i have, to this day, is, was that film really appropriate for children?