Where are the egg shells

[john-schneiderman@cox.net]

Bakker (1990) described tightly-packed pods of 6 to 35 individuals which 
he interpreted as representing groups of Drinker in burrows, perhaps 
drowned by flooding or killed by disease. If Drinker was indeed a 
burrower, it would be among the first known for dinosaurs; the only 
well-supported published case of a fossorial nonavian dinosaur is the 
more recently discovered, distantly related Oryctodromeus. One problem 
with Bakker's interpretation was the lack of fossilized egg shell 
fragments amongst the individuals which he stated (1992) was a family 
group of many juvenile/hatchlings with adults within a nesting burrow 
found in Como Bluff, Wyoming.

Supporting the nesting burrow idea, is it possible that a behavior 
amongst Drinker, and possibly other small ornithopods, were for the 
adults to consume the egg shell fragments after the the babies hatched 
as a means to replenish their loss of calicum, and thus no egg shell 
fragments to be found in the nest? Egg and egg shell eating is common 
amongst the birds ("Dinosaurs") today.

References:

-- Bakker, R.T., Galton, P.M., Siegwarth, J., and Filla, J. (1990). A 
new latest Jurassic vertebrate fauna, from the highest levels of the 
Morrison Formation at Como Bluff, Wyoming. Part IV. The dinosaurs: A new 
Othnielia-like hypsilophodontoid. Hunteria 2(6): 8-14.
-- Bakker, R.T. (1990). A new latest Jurassic vertebrate fauna, from the 
highest levels of the Morrison Formation at Como Bluff, Wyoming, with 
comments on Morrison biochronology. Part I. Biochronology. Hunteria 
2(6):1-3.
-- Bakker, R. T. (1997). "Dinosaur mid-life crisis: the 
Jurassic-Cretaceous transition in Wyoming and Colorado". In Lucas, S.G., 
Kirkland, J.I., and Estep, J.W. (eds.). Lower and Middle Cretaceous 
Terrestrial Ecosystems. New Mexico Museum of Natural History and Science 
Bulletin 14. New Mexico Museum of Natural History and Science. pp. 
67–77.
-- Varricchio, David J.; Martin, Anthony J.; and Katsura, Yoshihiro 
(2007). "First trace and body fossil evidence of a burrowing, denning 
dinosaur". Proceedings of the Royal Society B: Biological Sciences 274 
(1616): 1361–1368.
-- Dinosaur Parents, Dinosaur Young: Uncovering the Mystery of Dinosaur 
Families By Kathleen Weidner Zoehfeld;  HMH Books for Young Readers 
(January 22, 2007) ISBN-10: 0618752447 pgs: 31-32.