I posted this in another thread and I think it's appropriate to repost here in case people didn't see it there.
As one of the few actual wildlife biologists in this forum, I feel that I do need to explain a bit of the science behind this issue. A lot of reptile enthusiasts are understandably frustrated with the politics surrounding Burmese pythons in Florida, but let's please not confuse the actual on-the-ground science with the fear mongering on Capitol Hill.
The major challenge we as biologists face in any estimation of population size is a probability called "detectability." We can account for detectability in our statistical models if it is known, and these mathematical models are the most robust estimates we have in our statistical toolset for estimating populations. We use population estimates to manage anything from wild game (such as deer, turkeys, quail, etc.), invasive animals (Burmese pythons, feral cats, feral hogs, etc.), to recovering endangered species (spotted owls, sage-grouse, red-cockaded woodpecker, etc.).
You can think about detectability in the following context. The hunters in the audience will understand where I'm coming from, but there are plenty of non-hunting examples out there too.
I've gone hunting for feral hogs many times and have never seen one, despite their super abundance in some areas. Nobody questions that feral hogs do a great deal of damage. I've gone deer hunting for thousands of hours and have a relatively low success rate when you look at the ratio of time spent versus number of deer I've killed and seen, yet no one seems to argue that deer/vehicle collisions are a problem or that we have a lot of deer in some areas.
Invasive species are a problem. Just because the Burmese python issue has gotten a lot of fear mongering press and has a lot of political nonsense associated with it does not mean that Burmese pythons aren't a problem. They're a big snake in an area that has never had giant snakes before. It is reasonable to assume that the native wildlife is unaccustomed to being hunted by this particular brand of giant predator. Out of sight should not be out of mind.
When we (meaning wildlife biologists) are trying to estimate the number of animals in a population, our population estimates are based upon something called "detectability." If you fail to see an animal (or its sign) in the field, that failure is based upon two probabilities: 1) that you didn't observe the animal because it wasn't there, or 2) that an animal was actually there but you failed to see or "detect" it.
This hunt will, hypothetically anyway, allow biologists to increase the precision of our population estimates for Burmese python because it will allow us to estimate what that "detectability function" actually is. For a species as cryptic (aka hard to see) as a Burmese python, I can imagine detectability is very low.
For a real-world example, biologists over in Europe have estimated detection probabilities for several species of snakes. The probability of detection is highly dependent upon population size... at low population sizes, detectability is very low. The following data were taken from:
http://www.jstor.org/discover/10.230...21101552516103
Detection Probabilities for 3 species of European snakes
The following probabilities are arranged for low, medium, and high population sizes:
asp viper (Vipera aspis: 23%, 50%, and 70%
smooth snake (Coronella austriaca): 9%, 45%, 56%
grass snake (Natrix natrix): 11% for small, 25% for medium/large pop'ns
Keep in mind that these detection probabilities were estimated from biologists who had search images for these species and were very good at locating snakes. These are trained professionals, not the everyday public, so their detectability estimates are likely higher than this Burmese python hunt will generate. These estimates are also for heavily surveyed individual sites, not over an entire range a species could possibly inhabit.
The take home message from all of this is that snakes are very good at hiding. We have statistical tools to estimate populations based upon real data. Is it perfect? No. However, we can't assume that just because we didn't capture a whole lot of Burmese pythons that there aren't a whole lot out there, it simply means that we may have failed to detect those that are. That's why we need to keep looking. More data = better science.
Please do not attack the scientists for trying to learn more about Burmese pythons in the everglades. Not every scientist was involved with the non-peer reviewed USGS report. It takes time to learn the answer to tough biological questions like this, and considering our current economic hardships it's been very, very difficult to get funding to do any kind of decent research. I'm glad they thought of a creative way to get their data and I have high hopes that something productive will emerge from this new information.