Quote Originally Posted by Steveo View Post
Some birds are the same way. If a couple eggs disappear early in the incubation period, they'll lay a couple more to have a full nest.
True. I used to breed and raise fancy pigeons. If I wanted more babies out of a particlular pair, I would wait until they lay their second egg and then take it right away before incubation starts. I would then place it in the nest of another pair that are only incubating one egg. Then the pair I stole the egg from would just lay another. That way I get 3 babies, not just two. (brood size is always just one, or two with pigeons)

If I wanted to prevent a pair from laying eggs/raising babies, I would steal their eggs during the laying or incubation phase, and replace them with wooden ones. They would sit on the wooden ones and stop laying. If I didn't replace them with wooden ones, they would just lay more eggs.

I had a breed called "Chinese Owl". They can't raise their own babies at all because their beaks are too short to feed the babies. (for this reason, the breed is on the brink of extinction) The only way is to put their eggs in the nest of another breed. Keeping that other breed sitting on wooden eggs helps because I would switch the wooden ones for "Chinese owl" eggs.

Not so sure it works the same for getting snakes to "double clutch" since most snakes abandon their eggs anyway. I've never heard of garters double clutching but they can certainly have another litter the following year even if they don't mate again. I've had northwesterns give birth to 1-3 offspring several years after last male contact.