On this site you can download a pdf table describing the extremes of echolocation calls of European bat species. Please look below to find the table in your language. If you think you could provide us with additional information, or you see a mistake (also in language), don't hesitate to write.
-The free Avisoft-SASLab Lite Software has been modified and improved substantially, check out the sound analysis corner.
-Yet another new standalone bat-detector on the market: The Batlogger, see the Equipment section.
-I am presently testing a prototype of the Nanobat detector, will provide some first impresssions later.
-The new SM2 detector by Wildlife Acoustics is available. It now has a sampling frequency of 384 kHz and can compete with other detectors, see Equipment section.
-Check out the modified Ultrasound Gate 116Hnb and 116Hn by Avisoft.
-Hooray, the slovenian bat atlas (largely based on bat-detector observations) is now available here. The atlas is written in slovenian and english side by side. Praise to the authors for doing so much with so few people and little money.
-Look here. This is an online atlas, mainly based on bat-detector observations in SE France. Keep up the good work and thanks for putting these distribution maps online.
-Developments in Sweden: get the beta version of a programme to identify bat recordings   (read more)
-How the French do it: amorce et claquement final, a discussion of a method developed by Michel Barataud   (read more)-Un sondage pour trouver l'origine physique d'amorce. An acoustic survey to understand "amorce"   (cliquez ici)
Many of the previous approaches to IDing echolocation calls used datasets of random, average, or "typical" calls an observer would record in the field. We believe, however, that many calls one typically records in the field are of insufficient quality to analyse. One must record a series of high quality calls, characterized by a steep oscillogram onset, at best containing pulses of different durations. This means one gets few recordings of secretive quiet bats and a lot of pipistrelle-recordings, but then, bat detecting is a biased method anyway and what we really need is a reliable basis for identifying the recorded pulses. To make our table, we looked at large datasets of high quality recordings. We looked how far different bat species are able to "push" their echolocation in extremely dense and extremely open environments. This would give us some basic information what the highest and lowest values are a certain bat species is able to produce. The table shows these extremes per species, sometimes not very different, sometimes quite useful. The table is just a first step. Of course, we will also need to describe correlation between parameters that typify each species over its entire range between dense and open environment. We urge the users of this table to be extremely critical of it, warn us in case you doubt a certain value and never to go by it blindly. We hope to provide more parameters and ID information on this website in the near future. Because we received many questions and remarks about the table we added an FAQ to eliminate some common misunderstandings about the table. We also received a word of warning from Danilo Russo not to use the table blindly!
We (see the team below) tried to do our best to compile a table that is as accurate as possible to help everybody in Europe to use their time-expansion detector as well as possible. We hope that this website will become the centre of discussion about new findings, opinions, critiques, all to lead us to the perfect technique. We hope to start a discussion forum on this website, but you can write to us already with the latest novelties. Don't worry about language: we all speak and understand each other's Euro-english, and besides, you probably speak better English than your prime minister!
Of course, we have a certain philosophy regarding bat ID on the basis of echolocation calls. Our philosophy is to design an objective method that can be checked and verified every step of the way. Of course there are people with golden ears, but in the end of the day, what they hear is on the sound file, stored in a digital code. If the person with the golden ears insists that what he / she is able to hear is not to be found in any usual representation, such as an oscillogram or a spectrogram, he/she must find the representation that does show the magic cue, even if he /she must go down to the digital code itself. To be able to hear a cue, it must at least be in the digital code since this IS the sound. Following this logic, we claim that everything the best ear hears in a sound file can also be made visible on a screen. Our mission is to extract from the digital code all useful parameters, quantify them and get all Europeans to use them.