Summary of the research project conducted by Deakin University into occupancy of
Connecting Country nest boxes
In 2012 Deakin University Honours student Amy Monagle worked in collaboration with
Connecting Country to conduct a research project based on Connecting Country’s nest box
monitoring program. The aims of this project were twofold: (1) to assist Connecting Country
with their annual nest box monitoring program to determine the extent of nest box occupancy
by arboreal mammals across the Mount Alexander Shire; and (2) to investigate factors that
may be responsible for patterns in nest box occupancy observed for different mammal
species. A total of 300 nest boxes were inspected, consisting of three boxes spaced 50 m apart
at each of 100 sites spread across the Mount Alexander Shire. The design of the nest box
monitoring program is such that these 100 sites are located in both small (<50 ha) and large
(>50 ha) forest fragments, and in gully and upslope environments. At each of the 100 sites
detailed data was also collected relating to vegetation and habitat structure. This included
measures of the number, species and size of canopy trees, numbers of logs and stumps,
density of the shrub layer, and depth of ground litter. Data characterising forest fragments in
which nest boxes were installed was also developed, including fragment size and isolation.
Three arboreal mammal species were encountered in nest boxes: the sugar glider Petaurus
breviceps (total = 73 sites), brush-tailed phascogale Phascogale tapoatafa (total = 19 sites),
and common ringtail possum Pseudocheirus peregrinus (total = 1 site). Since the entrance
hole in the nest boxes is designed for the two smaller species, it was somewhat of a surprise
to observe a single common ringtail possum. Communal nesting was observed at only two
sites for the brush-tailed phascogale, whereas sugar gliders were almost always observed
nesting in small family groups.
Investigation of patterns of nest box occupancy revealed some interesting results. Sugar
gliders were more likely to occupy nest boxes that were installed on smaller trees and that
were located in forest areas with a low density of dead eucalypt stems but a structurally
diverse shrub layer. It is likely that nest boxes complement natural tree hollows for the sugar
glider, providing a greater choice of den sites within the territory of a family group. Nest
boxes also may provide alternative hollows for sugar gliders in areas where natural tree
hollows are limiting (but habitat is otherwise suitable). Patterns in nest box occupancy for the
brush-tailed phascogale were less clear. However, one pattern that was apparent was that nest
boxes were more likely to be occupied by brush-tailed phascogales when they were installed
in isolated forest fragments (as measured by the distance to the nearest forest area greater
than 500 ha in size). More research is required to understand this finding, but it is possible
that natural tree hollows are a more limiting resource for this species in areas where forest
cover is fragmented. Neither the size of the forest fragment in which nest boxes were
installed nor the topographic position (gully/slope) were useful predictors of nest box
occupancy for the sugar glider or brush-tailed phascogale.
This project has demonstrated the value of nest boxes for arboreal mammals, with boxes
being occupied throughout the Mount Alexander Shire. It is hoped that occupancy rates for
the brush-tailed phascogale will increase over time, resulting in a clearer understanding of
factors that determine nest box use by this species.
If you are interested in reading a more detailed account of Amy’s results, contact Connecting
Country (chris@connectingcountry.org.au).