This is a scientific technique I am gonna pen down, I have no expertise in this and don’t know the nuances of the issue also. It’s a simple effort to scribble the info available in the literature and books and online.
Its not only the media, concerns are all over India and world about steep decline in the tiger population in India. In general tigers are a species which is demographically distributed among 13 Asian countries. It is one of the rare royal species which is about to be extinct. In India there are 28 reserve forests 
for tigers and tiger census are carried out frequently. Wildlife Institute of India, Dehradun, came with a shocking revelation recently. they published a census report for tigers in 16 of these forests (rest they are going to publish in December 2007). It was shocking because they had reported a decline in tiger population by 60% in Madhya Pradesh, 57% in Maharashtra and 40% in Rajasthan. This decline took place within few years and the concern is, it happened in spite of govt. action to safe guard India’s national animal. Steady decrease in the no. is attributed to poaching and decrease in the habitat area. These big cats are extinct because of their big size and carnivorous diet which force them to reside in low population area. They are easy and prize targets for the poachers and reduction in the food availability is forcing them to be extinct, but there is other side of the story too: Some people believe that previously published census data was erroneous. In Palamou reserve forest the number of big cats may vary from 7 to 37! This takes us back to the process of counting the tigers. There is couple of techniques I am concentrating on here
Pug mark counting technique
This is quite old technique for tiger census; it was first used by W. J. Nicholson of Imperial Forest Service in Palamau district, Bihar in 1934. Then on this technique has gone through many versions of reforms and is still it is a topic for research. In this technique pugmarks separated by long distances are considered as individual tigers; among these the hugely varied marks are discarded. Using a multiple group discrimination technique it is possible to identify the track of individual tigers. It was found that seven such carefully identified pug marks can give a more or less accurate no. By the way pug marks are the footprints, shape of which gives the info of the gender too, usually individual cats follow different tracks , hence once the track is identified its is easy to count the no of tigers in a forest. It’s a time taking but an inexpensive method
Photo trapping technique
It’s a brain child of Dr. Ullas K. karanth, who is now in Bangalore. Pugmark technique although is being followed for quite sometime, it’s not a visual counting technique and secretiveness can not be taken care of easily. In this photo trapping technique, cameras are fixed near the track, as it is said that the stripes on the tigers body is similar to human face, hence it is possible to distinguish the tigers from the pictures and identify them next occasion. Tiger densities are calculated using statistical methods. Line transect sampling is used to find the tiger density. It is quite an efficient technique although several issues are still debated.
Except these there is a waterhole technique which is used in counting the number of tigers, but the important issue here is: is this counting technique varies the census results? Interestingly WII has used the photo trapping technique during the current census whereas the previous censuses followed the pug marks. In addition, forest official not always try to publish the factual info, just to avoid the exhibition of the decline in the no. of the tigers. Hence it’s quite a difficult blame game, but truth is tigers are in declining no. whether it is Suderbans or Ranthambore, they are endangered. Someone says correctly: it’s a losing battle!
for tigers and tiger census are carried out frequently. Wildlife Institute of India, Dehradun, came with a shocking revelation recently. they published a census report for tigers in 16 of these forests (rest they are going to publish in December 2007). It was shocking because they had reported a decline in tiger population by 60% in Madhya Pradesh, 57% in Maharashtra and 40% in Rajasthan. This decline took place within few years and the concern is, it happened in spite of govt. action to safe guard 