In Parallèle, the identification of acoustic sequences specific reliability level is highly variable depending on particular species, quality recordings, the length and nature of the sequences . Variability induced by these biases results is even stronger than the unit of measurement is fine and precise, that is why units of stable measures against the "abiotic" factors are sought . Two indices are proposed: the percentage of points where the species is present and the number of minutes of activity per night when the species is present .
Katika Parallèle, utambulisho wa Utaratibu wa acoustic maalum kuegemea ngazi ni kutofautiana kulingana na aina fulani, rekodi quality, urefu na asili ya Utaratibu. Tofauti ikiwa na matokeo haya biases ni hata nguvu ya kitengo cha kipimo ni faini na sahihi, kwamba ni kwa nini vitengo ya hatua imara dhidi ya "abiotic" sababu ni walitaka. Fahirisi Barua ni mapendekezo: asilimia ya pointi ambapo aina ni sasa na idadi ya dakika ya shughuli kwa usiku wakati aina ni sasa.