State wildlife agencies have several different surveys they use to get their estimates for various species.
Some my require a permit or mandatory check station, and assuming that all are checked/tagged, they have an exact number. Granted some may not get checked or tagged, so that would be a minimum number in that case.
Another survey would involve sending out surveys to all the people who bought a trapping license and asking then how many of each species they trapped during the season. These are not usually sent to every person who bought a license, but will usually have a statical confidence interval. In other works, the believe it to be within +/- 5% of whatever the number is.
They may add to that data collected from another survey such as a big game surver that would be sent out to deer hunters where they record other game harvested during deer season. Again, this data is extrapilated within a staticical confidnce interval. I'm not a statistician, so I can't explain it farter than that.
Some my require a permit or mandatory check station, and assuming that all are checked/tagged, they have an exact number. Granted some may not get checked or tagged, so that would be a minimum number in that case.
Another survey would involve sending out surveys to all the people who bought a trapping license and asking then how many of each species they trapped during the season. These are not usually sent to every person who bought a license, but will usually have a statical confidence interval. In other works, the believe it to be within +/- 5% of whatever the number is.
They may add to that data collected from another survey such as a big game surver that would be sent out to deer hunters where they record other game harvested during deer season. Again, this data is extrapilated within a staticical confidnce interval. I'm not a statistician, so I can't explain it farter than that.