THE BUFFON PROBLEM AND THE BERTRAND PARADOX - REALIZATION IN THE MARGINAL EFFECT DURING CENSUSES OF SMALL MAMMALS BY TRAP LINES

During long-term censuses of rodents by trap lines, the daily probabil ity of catching inhabitants of the test zone is proportional to the nu mber of traps per rodent. It depends on the way in which individual ho me ranges are crossed by trap lines: through the center, laterally, ev en tangentially. The capture per day changes exponentially in each var iant. It decreases more rapidly in central crossings, whereas in later al crossings, where animal abundance is lower, the decrease is delayed . This effect increases when the duration of capturing is greater and distances between traps are smaller. This may be evidence that migrant s enter in the catch zone as resident rodents are eliminated.