Rivers as possible landmarks in the orientation flight of Miniopterus schreibersii

Abstract

This study examines the initial orientation of M iniopterus schreibersii (Kuhl, 1817) when released from their roosts and analyses the significance of rivers as landmarks in bat navigation. Two orientation tests were carried out in which the bats were released in areas familiar to them and two further tests were carried out in unfamiliar areas. In both types of areas one of the tests was performed close to a river and the other away from a river. Initial orientation capability of M . schreibersii was verified in all tests except in unfamiliar area away from a river. The test performed in unfamiliar area with river showed higher mean angular deviation and lower directionality than the two tests performed in familiar areas. M ost of the bats released near a river both in a familiar area and in an unfamiliar one turned towards the watercourse. The results obtained in these two last tests proved that the bats tended to turn towards the river. There were no significant differences between the directions taken by males and females in each of the four tests. Rivers seem to be landmarks in the navigation of the species and also paths to be followed in migratory flights.Instituto Pirenaico de Ecología (C .S .I.C .), avenida M ontañana 177, Apartado 202,

Use of foraging habitats by bats in a Mediterranean area determined by acoustic surveys: conservation implications

“…Vaughan et al (1997a) showed rivers and lakes to be the main foraging habitats for P. pygmaeus in England. 3.0 (1.4) 2-5 3 -5 2 -5 2 -6 1 -5 1-5 Range 3-9 3-6 5-12 c a, b, c limited to foraging, as this species seems to follow rivers as navigation landmarks (Sierra-Cobo et al 2000). As these authors pointed out, elevation (as well as other unknown environmental factors) might influence the relative distribution of the two pipistrelle species.…”

Foray Search: An Effective Systematic Dispersal Strategy in Fragmented Landscapes

“…However, such a search strategy could only lead to high habitat patch detection in adequate landscape configurations (e.g., Boudjemadi et al 1999), making it of less general relevance than the other systematic search strategies. Moreover, individuals might disperse along landscape features in order to be able to retrace their steps (Serra-Cobo et al 2000) rather than because such a search strategy leads to higher patch detection efficiency per se. In this case, movement along landscape features could even be part of dispersal forays if unsuccessful individuals turned back.…”

Dynamic adjustment of echolocation pulse structure of big-footed myotis (Myotis macrodactylus) in response to different habitats

“…Hunting over water provides a number of benefits for insectivorous bats, including abundant prey (Fukui et al, 2006), high-quality commuting paths (Serra-Cobo et al, 2000), and sensory advantages in prey detection (Siemers et al, 2005). Clutter levels of riparian zones also vary based on factors such as water turbulence, vegetation density, and the expanse of water involved.…”