Bat roost boxes at Organ Pipes National Park, Victoria: seasonal and annual usage patterns

Abstract

Organ Pipes NP in NW Melbourne is a replanted eucalypt woodland where timber bat boxes of Stebbings' English design were installed in 1992 and first used late in1994. The bats found have been over 90% Gould's and 7% Large Forest Bats. Boxes of 6 different designs were tried over 15 years, differing in internal dimensions and entrance slit size, ranging from 0.002m 3 to 0.009m 3. The first ten boxes are used only in warm months, September to February. Three fallen boxes were replaced with smaller pinus boxes, which are used over more of the year. In 1996 some boxes, conforming more to Stebbings' design, were added, which are used for a yet wider seasonal range. Another set of smaller boxes have been used mainly in cooler months, and are avoided in summer. A set of boxes made of 45mm timber are also used in colder months. Annual patterns of box usage are examined for the different box designs-some show slow build-up, usage of others fluctuate up and down in cycles of several years, or are well used but avoided for some whole years, or are little used but come briefly into favour for one year. Box orientation affects usage patterns, those facing west or east being used much more than those facing north or south, and in different seasonal patterns. Where two boxes share a tree, complementary patterns may appear, one favoured in warm months, the other in colder months. An unexpected increase in usage in 2007-8 involved two bouts of breeding. Implications for study of natural hollows are discussed.

Limited use of bat boxes in a rural landscape: implications for offsetting the clearing of hollow‐bearing trees

“…gouldii was positive, with use, although highly variable, increasing with time since installation. An increase in box use over time has been reported previously (see Rueegger ), with some studies documenting an increase in box uptake over a 10‐year period (Boyd & Stebbings ; Bender ). However, box use estimated for Nyctophilus showed a slight decrease over time.…”

“…The low box use documented in this and previous Australian studies and lack of species diversity or lack of maternity roosting (e.g. Calder et al ; Smith & Agnew ; Bender ; Rhodes & Jones ; Griffiths et al ), indicates that our knowledge of implementing bat box programs is inadequate to achieve an effective conservation outcome for most Australian bat species. This suggests the importance of implementing a hollow‐bearing tree clearing avoidance strategy wherever feasible.…”

“…]), with tight‐fitting entrances postulated to be important for some species (e.g. Ruczyński & Bogdanowicz ; Bender ; Rueegger et al ). Furthermore, the “small” and “medium” box designs provide a small volume which is unlikely to be attractive for maternity roosting, particularly for species forming larger colonies (e.g.…”

Specific nest box designs can improve habitat restoration for cavity‐dependent arboreal mammals

“…This has been done for some bird species though the species involved are often those that readily use human‐modified areas (Katzner et al ; Corrigan et al ; Altwegg et al ). There is also evidence that insectivorous bat populations can be supported by artificial cavities (Stebbings & Walsh ; Flaquer et al ; Baranauskas ; Bender ). In contrast, evidence for cavity‐dependent non‐flying arboreal mammals is equivocal because non‐flying arboreal mammals may show a relatively low frequency of use of nest boxes (5–8% of boxes, Menkhorst ; 8–23%, Rhind & Bradley ; 8–14%, Lindenmayer et al ; 15%, Durant et al ; 20%, Madikiza et al ; 22%, Franco et al ; 8%, Veiga et al ; 2–12%, Warakai et al ; 13%, Williams et al ).…”

Low Rates of PIT‐Tag Loss in an Insectivorous Bat Species

“…Most of the native eucalypt (Eucalyptus spp.) trees are currently <45 years old and lack hollows (Bender 2011). The vegetation is predominantly riparian grassy woodland, with a sparse patchy understory of wattles (acacia [Acacia spp.…”