From 1997 to 2002 several hundred trees of sallow (Salix caprea) and aspen (Populus tremula) at the edge of forests were examined; 83 Macrolepidopteren taxa were detected on sallow, 65 on aspen. The Poplar Admiral (Limenitis populi), the Purple Emperor (Aatura iris) and the Lesser Purple Emperor (Apatura ilia) are three elusive woodland species, decreasing in population numbers in the last decades. This was depending on an intensive and productive forest management, which doesn't tolerate the prefered larval feeding trees alongside forest roads. Recently there is an interest to be conductive with endangered species also in intensively managed forests. In this article the biology and the prefered habitat sturctures of the three taxa depending on the examination were presented. Typical attributes of the species, the manner of feeding, the hibernation and the location at the feeding tree are shown and discussed. To detect or evaluate the population size typical stages of the metamorphosis at outdoor examinations are shown. The most efficient time to get an impression of the populations and the used habitats is searching the young larvae and the typical grub in August and September. The typical habitat of Apatura iris is characterized in half-shady, normally canopy-covered forest edges in the inner forests, the two other specimen settle on similar, but more sunny expositions. Indications for practical protection of these habitats are given, but significant acception by the management is assumed.
