to follow up with a thread below regarding Gila nesting (from ZX)...
first of all, the stuff we are doing with Gilas is still just theory and educated guesswork. i would say we would need a number of consecutive strong-result breeding seasons to really be "authoritative" on the matter. certainly folks like Doc Seward have had much more success than us, using different methods, and so while i really enjoy talking with him about Gila husbandry, theory and strategies, i am NOT going to say that ours is the be-all-to-end-all 
we base a lot of our Gila strategy and theory on our experience with breeding monitors. i believe they have more in common than not, and a lot of that theory is easily applicable.
struggling with Gila breeding over the years, and having good success keeping and breeding monitors, i see that a major obstacle to more successful captive Gila breeding is in the nesting. we could talk about nesting for hours upon hours, but very basically, and quickly, many breeding problems, including weak eggs, bad eggs, slugs and general lack of healthy eggs can be traced to poor nesting.
if there is not an appropriate place for a female to lay her eggs, it triggers a whole sequence of problems that lead to poor, or zero, hatching.
there are no incubators in the wild. Gilas lay and hatch right in the ground, in soil, and they have done so for millions of years. as captive breeders, we use incubators because it takes away a significant variable where any number of things can go wrong.
certainly there can be problems in incubators, lots of problems, but you are bound to have more success than if you were to just leave fresh eggs in some cage in a clump of sphagnum with no real temperature or thermal mass control. this is not so for a good soil substrate. it has good stable temperature and moisture properties, due in large part to its large thermal mass.
when a Gila female digs an egg burrow and deposits eggs in a properly setup deep soil substrate, she is choosing a particular spot according to temperature, humidity, and well, survivability. that is assuming that you are giving her a variety of choices so that she can find that appropriate spot.
in a more traditional setup, like a Vision cage with some Sphagnum or other similar substrate (been there, done that), you are not getting a nesting and laying of eggs so much as a "dumping" of eggs, and from previous lizard experience, it is no wonder that there is such a poor hatch rate from dumped eggs, they are handicapped from the first step.
the wild eggs naturally hatch out just great after 6 months in the soil, so digging them up an hour after being laid, or 24 hours, or 48 hours, is no problem. they are not being laid in a "compromised" spot, but rather, closer to ideal.
leaving your eggs sitting on top of sphagnum or 3 inches of potting soil for a day or two would be a really poor choice, on the other hand.
as for stressing out the females, i disagree. i think that our females are actually much LESS stressed in our setups because they have the tools to live a more natural life-style/cycle. they can dig and burrow, which increases the usable space of the cage many-fold, they have access to a wide range of temps, including basking spots that top out at 130 F, and they have access to food as they need it.
the females are active, healthy, and have great follicular development during the breeding season. i wish we had a wider variety of males to pair of with these females during the breeding season, but we have a number of younger animals coming up, so that should remedy itself for the 2005 season
like i said, we have not "solved" anything Gila wise, but i think we are on the right track, and a bit more fine tuning as to pairing times and female cycling will hopefully work itself out over the next season or so.
Gilas are such a great animal, i would like to see a much larger group of hobbyists have more success in breeding (hatching) them. best of luck to all!
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robyn@proexotics.com
