Hungry Chicks...

[lexico]

are a lovely sight to see as Mama Bird (or Papa Bird) feeds their eager mouths.
I watched a nature documentary of the yellow-mouthed chicks crying for a worm, and it was so instinctively wonderful to watch them feed. But to see the cuckoo's chick pushing out one host chick after another, while the hostess did nothing was upsetting. How could a mother see her babies get killed and do nothing ? It is difficult to understand this behaviour because her neglect is not helping her genes to spread at all. Does the cuckoo give in return ? Or is the cuckoo only taking advantage of the unselfish (or dumb) gene of another bird while the niche is open for exploitation ?

Hatching and Feeding
feed me !
Me first !!
blackbirds feeding

 

[Kara_Nari]

Thanks for that... it was interesting! (not that funny though when mama bird died)

 

[f0rk0]

I think the mother doesn't do anything about it, as it sees the adopted cuckoo chick as the strongest, since it's also the largest, isn't it?

Anyway, I could watch birds go on with their daily activities with a dewy-eyed fascination.

 

[Horizon]

Adding on, it's also probably because then the surviving one will get all the food and all the attention the parents can give to it, which would probably make it stronger and, well...One strong chick going out into the world is better than having four, weaker, chicks doing the same.

There's a better chance for the surviving chick to continue to, well, survive this way.

Not to mention, population control as well possibly?

 

[lastmagi]

I think it has to do with the capacity for parental investment. An offspring requires a lot of energy expended on the part of the parents to provide them food. With a large clutch size, it is possible that parents may not be able to provide everyone everything. So as others have pointed out, there is a kind of "survival of the fittest" in a slightly more micro sense while the parents don't do anything.

Anyway, baby birds are a greedy bunch. Aggressive, too. Spending the summer mouth-syringing those little bastards their food as part of a job kind of knocked any romantic notions I had of them out of my head.

 

[Horizon]

Oh! And, also, I heard that, in the cases of birds that lay more than one egg, but the first chick that hatches kills the other ones, that the other eggs are just back-up.