Monday, September 22, 2008

Baby Boxes!!!

Late August into September is the time that box turtles hatch here in north Alabama. If you have never had the luck to see a hatchling box turtle then you missed out on cuteness extremis! Most references that I found on the subject of box turtle nesting report that the turtles seek out sandy soil. There is not much sandy soil here; where it exists (or more friable soil at least) is along the rivers in the bottomlands. Bottomlands are subject to flooding, and submersion of the eggs for more than just a short time would kill the eggs. The female turtles that I have found appear to move upland to lay their eggs in clay soils. My yard is aquatic turtle nesting site central. All of the aquatic turtles, with the exception of the snapping turtles, nest way up the yard. Near the lake, the water table is only about a foot below the surface, and during rainy periods, it is near the surface. I think that by going higher up the yard (uphill, not just away from the lake), they guarantee the eggs will not sit in water. They do not choose the looser garden or compost pile (once a turtle nested in the compost pile edge) they choose the hard clay. The nest that are upland in the yard do not suffer depredation; skunks and raccoons only seem to find them after the hatch and the nest has been already breached by the hatchlings. The snappers nest lower down in the yard on small hillocks. A particular favorite spot of the snappers suffered a tree downing. The stump was ground and this loosened the soil adding a lot of wood chips to it; all of this made the soil much more friable. The snappers flocked to this spot to lay, and all the nests were found and the eggs destroyed. Years later the chips are rotted away, but the soil is still easy to turn and occasionally the nests are destroyed. I think the clay soils with less organic material seals the scent of the nest. The friable soil of the snapper’s nest probably does not seal as completely. Well, it is a possible interpretation of my observations.

Box turtle nests are well camouflaged and difficult to find once the female turtle is done. After the babies leave the nest, it is not much more obvious than before they emerged. So do not feel bad if you have never found a nest or hatchlings either! When the hatchlings are ready to leave their dark and cozy egg chamber one of the babies punches out a small plug. Through this small hole, all the babies emerge. From the nests that I have seen, there seems to be one truly adventurous baby who opens the chamber; and when he is out of hole, he is out of there! Zip, zoom, gone! Baby number two generally is not so sure about the big wide world and is more cautious about moving out the chamber and leaving the area. After two leaves home, the others follow except for the last straggler. There usually is one reluctant baby who seems to think the whole idea of hatching and leaving is a really bad idea, and he can usually be found, headfirst back in his open eggshell. When I have popped the top of the chamber off and found the last baby I have it taken out of shell and always heads straight back for its shell! As cute as this delayed procession of emergence is, it might serve a purpose. It may increase the safety of the nestlings by spreading out their introduction to the world-if one is found and eaten the others are not right there next to it waiting to be picked off. One baby may die but the predator may not find the nest and give up allowing the other babies to live another day.

Hatchlings do not hatch and emerge immediately. They first must absorb their yolk sac. They can remain in the chamber for days before they leave. Some references speculate on clutches layed late in the year (some turtles lay a second clutch, usually in August) the babies hatch out and over winter in the nest chamber. I have seen lots of second clutches that never develop. A second clutch I was raising, over wintered, and successfully hatched, but the mother had buried them deep and they never emerged; by the time I dug them up they were dead (that was in February-too cold for them to have survived on their own anyway. This is the only time I have seen second clutches survive. It stands to reason that enough second clutchers must make it adulthood to select for this reproductive strategy trait. Perhaps the few that emerge from the nest in the spring have an advantage-may be more prey and more cover. The months to eat and grow before they have to hibernate may give them greater survivability through the winter. Perhaps the fall emerged babies cannot dig in deep enough to survive harsh winters, and spring emerge babies might be deep enough to survive had freezes. I do not know, there are not survivorship studies on box turtle hatchlings, but there are possibilities that are worthwhile exploring.

The babies in the pictures emerged the first week of September. They represent two different clutches. A third clutch died in the shell-the whole clutch (perhaps disease). I have seen some eggs that fail to develop; I do not know if they are infertile or other reasons, but they all seem to be attacked by molds. The pictures of the baby upside down show his umbilical scar from the absorbed yolk sac. Once hatched, the babies appear to dig into the duff or moss. I suspect early in life, in a forested environment, they just stay dug in where it is moist and wait for dinner to come to them. For their first few years, they are extremely vulnerable. They cannot close their shells, their shells are not that strong-not enough to withstand teeth-and they are small and swallowable. They are hors-d’oeuvres waiting to happen! I am amazed that any baby boxes escape the sensitive noses’ of skunks, raccoons, and opossums, and probing beaks of herons and crows! I am glad enough do make through their early years! Boxes are interesting animals, and it sure doesn’t hurt my interest in them that they are soooo cute as babies!!! The picture below is a baby next to a quarter; sometimes they are barely bigger than a nickle!

An excellent book that reviews the scientific literature of box turtles is: C Kenneth Dodd Jr., North American Box Turtles: A Natural History, Animal Natural History Series v. 6, University of Oklahoma Press, Norman, OK, 2001.

2008 © Pam Croom


Appalachian Lady said...

Wow--I have never seen baby box turtles but I have seen a lot of box turtles--pretty large--around here. Thanks for all the information and the reference on box turtles. Great post and the photos make me want to go out and look for turtles. Joan
P.S. Thanks for visiting my blog today.

nina said...

I have always wished I would find one!
I've been a boxturtle lover for years, and have come across several on our trails, so I know they're around.

Never any as small as a hatchling.
I'll keep looking.
Your find is fantastic!

me ann my camera said...

What a wonderful read this has been. Your descriptions of the hatching process of this little box turtle is fascinating. And it looks so small in your hand, looking very much the same size of a baby Snapping turtle. I am so glad to have found your blog and I especially love your choice and painting with words of the Red-winged Blackbird warrior in your most recent posting.

Pam Croom said...

Thank you for stopping by. They do look about the same size don't they...but only about a quarter in number at 4-5 instead of 20. Snappers are big, but that 20 is pretty extraordinary!

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