Thall you are exactly right habitat destruction is one of the major problems to the reduction of rabbits and quail. Also the predator factor is huge,because there are very few people that engage in trapping.The booming turkey population also contributes, because it seems eveything picks on the baby rabbits and quail, turkeys will scratch over a nest and disturb or kill the babies in the nest.
Missouris rabbit populations are a direct result of habitat improvements and the abundance of public land. Missouri has a 1/8 of a percent sales tax for conservation, and the state continues to purchase land and then allow areas to growover, burnoff fescue, and plant wildlife food plots. Missouri publishes thier conservation map (Outdoor Missouri) with all of thier WMA's, they cannot update the map fast enough, they really have alot of places to hunt! I have went and hunted WMA's all over the state for turkey, just picked a spot of the map, and was rarely disapointed.
I have also witnessed areas in Northern Kentucky where the Fish and game dept were consulted about habitat improvement, then burned off Fescue, and added native grasses, and the rabbit population boomed back like it was in the 60's. While other areas nearby you are still lucky to kick up 1 rabbit.
It has to be seen to believe.

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