Gulls usually lay only 3 eggs. How do gulls "know they should lay three eggs?

Question

include a sorce or your question won't even count.

Answer 1

I don't know your source so I can't repute it, but if gulls only lay three eggs it is because they are genetically programmed to do so.

In some species of bird if more than one egg is laid the chicks have to fight it out and the parents will stand by and not feed them until one chick is killed by the other chick. The parents will then throw that body out of the nest forgetting it. No, I don't remember which nature show I saw this on, but when you see a chick kill another one on camera it is hard to forget the scene.

Answer 2

this is their clutch size coz at their environment this is the best strategy....if they had laid more then they cant rear and less then it will be a wastage coz they had potential for more

the whole thing is a Evolutionarily Stable Strategy....and is genetically programmed...