Radio-tracking Studies of Common Ringtail Possums, Pseudocheirus peregrinus, in Manly Dam Reserve, Sydney

12 Pages·2003·4 MB·English

by  Barbara Smith

Common
Radio-tracking Studies of Ringtail Possums,
Pseudocheirus peregrinus, in Manly Dam Reserve, Sydney
Barbara Smith\ MichaelAugee^ and Stefan Rose^
Biological Science, University ofNSW, Sydney 2052
NSW
^Current address: 185 Morgans Road, Mount White 2250; ^Current address: Wellington Caves Fossil
NSW
Studies Center, 89 Caves Road, Wellington 2820; -^Current address: Ecotone Ecological Consultants
NSW
Pty Ltd, 39 Piatt Street, Waratah 2298.
(This paper edited by J-C. Herremans)
Smith, B., Augee, M. and Rose, S. (2003). Radio-tracking studies of Common Ringtail Possums,
Pseudocheirus peregrinus, in Manly Dam Reserve, Sydney. Proceedings ofthe Linnean Society ofNew
South WalesllA, 183-194.
In radio-tracking studies in Manly Dam WarMemorial Reserve, Common Ringtail Possums were found to
survive an average of 319 days, with 80% ofknown deaths being due to predation by foxes and cats. The
smdy areacontainedfewlargetrees withhollows and 88% ofthenestsitesusedweredreys.Any dreymight
be used by several possums, although rarely simultaneously. Ringtails were found to be sedentary, usually
occupying dreys and foraging within a Banksia ericifolia thicket. Only 37% of the radio-tracked possums
m
moved morethan 50 fromtheirpointofcapture, and such movements oftenresulted in the establishment
ofa new foraging range. Males were more likely to make such shifts than females.
Manuscript received 10 Oct 2002, accepted for publication 6 January 2003.
KEYWORDS: Common Ringtail Possum, drey, home range, Pseudocheirusperegrinus, radio-tracking.
INTRODUCTION
from simple depressions to fully Uned shelters similar
to arboreal dreys.
This paper reports a long-term study (1994- Most of the possums radio-tracked in the Ku-
1999) of Common Ringtail Possums, Pseudocheirus ring-gai study were introduced into the area and it is
peregrinus, intheManlyDamWarMemorialReserve. possible that their behaviour was atypical compared
It complements and extends an earher study (Augee to lifetime residents. The Manly Dam Reserve study
et al. 1996) carried out in Ku-ring-gai Chase National was based on resident, "wild" ringtails and was
Park. The latter study was terminated by fires which designed to determine if the high levels of predation
burnt the study area in January 1994. and patterns of nest usage reported by Augee et al.
The Ku-ring-gai Chase study found mean (1996)areawidespreadoccurrenceorsimplytheresult
survival ofCommon Ringtail Possums to be 101 days of unusual conditions prevailing in the Ku-ring-gai
afterthecommencementofradio-tracking. Itprovided Chase study.
the first quantitative evidence of high levels of TheManlyDamReservestudysitewasselected
predation on possums by foxes and cats (Rose et al. because it seemed likely to be less susceptible to
1994, Augee et al. 1996), perhaps related to the bushfire than Ku-ring-gai Chase. That assumption
unexpected finding that up to 10% of the nest sites turnedouttobeincorrectaspartofManyDamReserve
were on the ground (Augee et al. 1996). Unlike other didbum,butonlyafterthis studywascompleted. Both
possums, ringtails are not dependent on tree hollows studiesareasareSydneysandstonewoodland, although
for nesting sites. They use tree hollows but also ManlyDamReservecontainsrelativelyfewlargetrees
construct free-standing nests, known as "dreys", that with hollows compared to Ku-ring-gai Chase.
are often mistaken for birds' nests. Ringtail dreys are The Manly Dam Reserve study was designed
larger and more spherical than those of birds except not only to provide data on survival and nest usage of
for some babblers, none of which occurred in either wild Common Ringtail Possums, but also to run long
study area. Nests on the ground were usually enough to gather data on long term movements and
constructed in grass clumps and varied in structure dispersalofindividuals andintraspecificrelationships.
MOVEMENTS OF COMMON RINGTAIL POSSUMS
In the course of radio-tracking incidental data were shrubland and heathland on Hawkesbury Sandstone.
obtained, particularly in regard to reproduction. Fivevegetationcommunitieswere identifiedwithin the
Manly Dam Reserve study area:
Banksia ericifolia Thicket: Scrub to 4 metres height
MATERIALS AND METHODS and 60-70% cover. Predominantly Banksia
ericifolia, with Kunzea ambigua and Hakea
The study area teretifolia.
The study area comprised 8 ha in the north- Low Open Woodland: Low eucalypts to 8 metres at 3
west comerofthe Manly DamWarMemorial Reserve - 4 metre intervals. Dominated by Red Bloodwood
as shown in Fig. 1. Its topography was undulating Corymbia gummifera and stringybarks. Sparse
and consisted of moderately sloping hillsides around shrub layer and dense sclerophyllous ground layer.
the headwaters ofCurl Curl Creek and tributaries. The Heathland/Low Open Woodland: Dense low shrubs
vegetation was predominantly dry sclerophyll and grassland to 2 metres, with areas of low, scat-
SVudy
Area
Figure 1. The study area in Manly Dam War Memorial Reserve.
184 Proc. Linn. Soc. N.S.W., 124, 2003
B. SMITH, M. AUGEEAND S. ROSE
tered eucalypts to 8 metres. Briefly, intact transmitter collars with little distortion
Open Forest: Trees to 20 metres and 30 - 40% cover. found in association with scattered fur but no body
Dominant species include Sydney Peppermint £«- parts were scored as fox kills. Cached collars and
calyptuspiperita,Smooth-haikedAppleAngophora collars located a considerable distance from the last
costata.RedBloodwoodCorymbiagummifera. Sil- recorded nest site were also scored as fox kills.
ver-top Ash E. sieberi and stringybarks. However mangled corpses or collars found with body
Riparian OpenForest: Trees to 20metres heightalong parts (usually heads, paws, intestines and often the
thebankandfloodplainofthecreekline.Dominated caecum) were scored as cat kills.
by Black Wattle Callicoma serratifolia and euca-
lypts with a shrub layer ofBanksia ericifolia and a Foraging and home ranges
ground layer with sedges such as Gahnia spp. and In a separate study ofringtails carried outby
Coral Fern Gleichenia spp. Newton (1997) at Manly Dam, the areas used by
individual ringtails foraging around their nesting sites
Animals were found to average 0.020 ha forfemales and 0.034
Seventy-nine ringtails were caught in the ha for males. These foraging ranges had a maximum
study area and fitted with radio-collars. They were diameterofabout50m.Inthepresent,long-termstudy
m
designated with numbers 242-320. Sex is indicatedby therefore we considered movements less than 50 as
the prefix F for females and M for males. Individual foraging movements and movements over 50 m as
details are given in Appendix I. Individuals weighing exploratory. These longermovements may ormay not
less than 600 g were classified asjuveniles. have resulted in a shift of foraging range. When
Forringtailsthathadbeenfollowedsincethey ringtails were foundtoestablish anewforagingrange,
m
werepouchyoung, theirmotherwas ofcourseknown. new nest sites more than 50 from theirprevious site
We were able to identify probable fathers in cases wereconsideredtobedispersal.Weusetheterm"home
wherenestsharing with the motherhadbeen observed range" torefertothe sumofallforaging areas usedby
at about the right time for conception and where nest anindividualthroughoutthecourseofthestudy.Home
sharing between an adult male and the juvenile was ranges areillustratedin figures by the smallestconvex
observed. polygon that can be drawn to connect the outermost
recorded nest sites. Only data for those animals (62
Radio-tracking system out of 79) that were tracked for more than a month
Ringtails were caught by shaking them from were used in determination ofhome ranges.
lowlyingtreesorbushes,fittedwithradio-transmitters
builtinto collars and subsequently locatedby tracking Survival statistics
the radio signal as described inAugee et al. (1996). Where mean survival is given it has been
The process ofcapture and collaring usually calculated only for individuals whose date of death
resulted in the animal moving to a nest other than the could be determined.
one in which it had been captured, but on only one Survival functions for various data subsets
occasion was that nest site out of the foraging range. were estimated using software provided by K.H.
One individual (F245), after it took several attempts Pollockbasedonhis(Pollocketal. 1989)modification
to recapture her and replace a faulty transmitter, for staggered entry of animals of the Kaplan-Meier
dispersed immediately by 110 m to a new foraging product limit estimator (Kaplan and Meier 1958) as
range in which she remainedfor more than two years. detailedinAugeeetal. (1996). The survivalfunctions
inthis study andtheprevious Ku-ring-gai Chase study
Data collection (Augeeetal. 1996)werebasedonweeklyobservations.
The position of each Ringtail was usually
determined weekly, although more frequent
RESULTS
determinations were oftenmade inthe firstfew weeks
afteracollarwasfitted.Thenestsite(drey, treehollow,
ground nest or other) was recorded. Survival
When radio collars were replaced in orderto The mean survival of all ringtails was 319
change batteries, pouches offemales were examined. days after commencement of radio-tracking (n = 60,
The presence and estimated weight of any joeys was SD=336,median= 172days).Meansurvivalofadults
noted.Approximatedateofbirthwasextrapolatedfrom was 465 days (n = 33, SD = 374, median = 371 days).
the growth curve published by Smith (1995, p. 37). Mean survival ofjuveniles was 140 days (n = 27, SD
Probablecauseofdeathwasdeterminedfrom = 156, median = 90 days).
corpsesusingthecriteriasetoutinAugeeetal. (1996). Themeansurvivalofallresidentringtailswas
Proc. Linn. Soc. N.S.W., 124, 2003 185
MOVEMENTS OF COMMON RINGTAIL POSSUMS
-SURVIVALKu-ring-gaiWild
-SURVIVALManlyDamWild
i
3
V)
300
Figure 2. Comparison of Kaplan-Meier survival functions (modified for staggered entry) for all wild
ringtailsradio-trackedatManlyDamReserve(n=78)andKu-ring-gaiChase(n=41).Chi-squared= 10.227;
P<0.01.
much greater at Manly Dam Reserve (319 days) than Figure 3 compares the survival functions for
at Ku-ring-gai Chase (182 days). The Kaplan-Meier juvenile andwildringtails atMany Dam Reserve. The
survival functions, modified for staggered entry of relatively low survival function forjuveniles is highly
animals, for all wild possums tracked at Manly Dam significant ( Chi-squared = 13.069, P<0.001).
Reserve and at Ku-ring-gai Chase are shown inFig. 2.
The survival function for the Manly Dam Reserve Predation
population is significantly lower (Chi-squared = The fates of all 79 resident ringtails radio-
10.227, P<0.01). tracked are shown in Table 1. Predation by introduced
-SURVIVAL Adult
-SURVIVALJuvenile
i
CO
Figure3. ComparisonofKaplan-Meiersurvivalfunctions(modifiedforstaggeredentry)foradultringtails
(top curve, n=44) andjuveniles (n=34) at Manly Dam Reserve. Chi-squared = 13.069, P<0.001.
186 Proc. Linn. Soc. N.S.W., 124, 2003
B. SMITH, M. AUGEEAND S. ROSE
Table 1. Fate ofCommon Ringtail Possmns tracked in Manly Dam Reserve 1994-1999 and Ku-
ring-gai Chase National Park 1990-1994
FATE Manly Dam Ku-ring-gai Ku-ring-gaiIntroduced
Wild
Killed by fox 28 18 39
Killed by cat 20 4 28
Radio-signal lost, reason undetermined 12 8 27
Killed on road 9 1
Still alive at end ofstudy (collarremoved) 4
Transmitter failed, seen but notrecaught 3
Killed by python 1 3 5
Killed by goanna 1 6
Killed by raptor 1 2
Killed by unknown predator 1 4
Killed in bush fire 4 1
Total 79 38 113
carnivores (foxes and cats) was heavy; 80% ofknown If this animal is excluded, only 4% of the locations
causes ofdeath (Table 1). were on the ground.
Nest sites Sharing ofnest sites
During this study a total of 2,907 daytime Dreys were used and kept in repair by more
positions was determined by radio tracking. Ofthese, than one individual ringtail. Table 3 lists single and
88%wereindreys, 6.1%wereonthegroundand3.6% multipleoccupanciesforallknownnestingsitesinone
were in tree hollows. thicket. The thicket illustrated had the greatest use of
Dreys were constructed in tree/shrub species any in the study area. Table 3 contains an example of
listedinTable2withthemajorityinBanksiaericifoUa. nest sharing within a family, with each parent (F266
Onaverage,individualringtailsatManlyDamReserve and M295) sharing with each other and on separate
used seven differentdreys during theperiodthey were occasions withoffspring (M307 andM308). F266also
radio-tracked. The actual number ranged from one to shared with her daughter F292, the father ofwhich is
21 depending mainly on the length of time any one unknown.
possum was tracked.
The figure for usage of ground positions Competition
(6.1%) is skewed by one individual (M275) that was There is some evidence for exclusion as a
located 70 times on the ground after having dispersed resultofcompetition.Intwocasesringtailsmovedinto
to an area of heathland where there were no shrubs, an area immediately after an occupying ringtail died
bushes or small trees sturdy enough to support a drey. (M261 replaced M244, and F242 replaced F243). In
Table 2. Characteristics offour thickets in the Many Dam study area. Common Ringtail Possums
listed as occupants did not necessarily overlap in time. Area and floristic data from Newton (1997).
OCCUPANTS THICKET SPECIES INWHICHNESTS OCCURRED
AREA
(ha)
M263, F266, M295, 0.165 Banksia ericifoUa, Kunzea ambigua and Corymbia gummifera
M307, M308
F242, M254, M279, 0.12 B. ericifoUa, K. ambigua, Hakea teretifoUa, andE. punctata
M300
M290, M297, F298, 0.18 B. ericifoUa, K. ambigua, H. teretifoUa, and E. haemastoma
F311
F136,M246,F248, 0.275 B. ericifoUa, K. ambigua, B. serrata, H. teretifoUa, and E.
F249, M282 haemastoma
F253, M264, M284, 0.16 B. ericifoUa, K. ambigua, CalUcoma serratifoUa, E. punctata
F287,M310 and Leptospermum trinervium
Proc. Linn. Soc. N.S.W., 124, 2003 187
MOVEMENTS OF COMMON RINGTAIL POSSUMS
Table3. Occupancy ofdreys in a single thicket by Radio-collared ringtails Table 5 shows that some
during the period 1994-1999. Cases where occupancy was simultaneous ringtails remain for extended
are indicated by / and bold. *M307 and M308 are siblings; M295 is their periods, in some cases their
father; F266 is their mother, ** F266 is the mother ofF292 entire life, in the same foraging
area (thicket) in which they
were bom.
Drey designation Occupiers
Cla M259/F132
CI F242,M263,M261,M289 Distributionofnesting sitesand
C2 M259/F266, M263, F285 home ranges
C3 F266A1259 Fig. 4 is a plot of all
C4 M295/F266, M308, M307 nesting sites on a map of the
C5 M259, M263 study area. All nesting sites for
C6 F285, M259, M263 any given individual are
C7 M259 enclosed in the smallest
C8 M263, M259 polygon that can be formed by
C9 M259, F266/M295, M263, M244, M261, F249, joining outer sites for that
M279/r292, M295/M307/M308* animal to form an estimate of
CIO F266, M259, M263, M244 home range. The distribution is
Cll M295
patchy across the study area
Clla F266/M307*
and the overlapping
C12 M263
concentrations of homeranges
C13 F289, M263, M279
correspond to the distribution
C14 M263
C15 M263/F277 ofthickets (Fig.4).Thethickets
C16 F277 were composed primarily of
C17 F266, M295, M263, M307/M308* Banksia ericifolia and Kunzea
C18 F289 ambigua. Details of the
C19 M259, F266/F292**, F289 floristics (from Newton 1997)
C20 F266, M295 offourthicketsinthestudyarea
C21 M295 ai"e given in Table 2. Nest sites
C22 M295/F266, M307 rarely occurred in large trees.
C23 F266, M307/M308* Over the entire period of this
C24 M295 study only five dreys were
C25 F266/M307, M295 found in Eucalyptus or
C26 M295
Angophora spp.
another case, M275 dispersed from the foraging area Reproduction
he had occupied for four months after another male, When the pouches of females at the time of
M264, incorporated that area into his own. M275 radio-collar replacement were examined, almost all
thereafter remained in his new foraging range. were found to contain joeys. Although Pahl (1987)
found numerous single births in southern Victoria, in
Movements this study all mothers with pouch young were found
Table 4 sets out all instances for ten to be carrying twins; not one instance of single birth
individuals in which exploratory movements from one wasfound. Pouch young were attachedtotheposterior
nest site resulted in the occupation of a new nest site pair of nipples (ringtails have two pairs of nipples in
m
morethan50 away.Thenumberofthesemovements the pouch). The annual distribution is shown in Fig. 5,
for an individual varied from one (F245) to 13 (F296) from which it appears that breeding occurs throughout
(Table 4). It is important to note that 39 of the 62 the year, with a peak ofbirths in May and November,
animals trackedformorethan one month did not make and a trough in January-March.
any exploratory movements and remained within 50
m
of the point at which they were initially captured
and collared. DISCUSSION
Forty-four percent of males tracked made
exploratory movementswhileonly 28%ofthefemales MeansurvivalofwildpossumsatManlyDam
did so. Reserve (319 days) was greater than determined for
188 Proc. Linn. Soc. N.S.W., 124, 2003
B. SMITH, M. AUGEEAND S. ROSE
bcinksia V V HeatWand/ Riparian
LOW Open Open Foirest
eriCHfolia
Woodlfand
Thicket
Figure 4. Home ranges (as defined in the text) ofall ringtails radio-tracked at Manly Dam Reserve 1994-
1999 superimposed on a vegetation map ofthe study area. Dots = nest sites. Vegetation communities are
defined in "Methods" above.
Proc. Linn. Soc. N.S.W., 124, 2003 189
MOVEMENTS OF COMMON RINGTAIL POSSUMS
Table 4. Examples of long distance movements by Common Ringtail the Ku-ring-gai study. The
Possums in Manly Dam Reserve. For each ringtail listed all known major cause of death is
m
movements over 50 are given. predation by foxes and cats;
80% atManly Dam Reserveand
Animal Distance (m) Duration (days) Terminal event 76% at Ku-ring-gai Chase.
F242 55 (from a to b) 18 Usage of ground nest sites is
55 (return to a) 14 also similar in both .studies; 6%
55 (return to b) 1140 killed by fox at Manly Dam Reserve and 7%
F245 110 741 killed by goanna at Ku-ring-gai Chase. The most
M254 122 7
likely explanation for the
105 14 road kill
apparently greater life
M261 50 36
expectancy at manly Dam
68 21
53 14 Reserve is lower numbers of
65 21 introduced predators, but there
64 539 is no way to testthis hypothesis
56 21 killed by fox with available data.
M264 75 28 Juveniles are clearly at
110 764 killed by cat greater risk than adults, having
M275 122 370 a significantly lower survival
88 7 function (Fig. 3).
65 78 transmitter failed The vegetationwithinthe
M279 65 (a to b) 7 Manly Dam Reserve study area
63 (return to a) 7
consisted mostly of low heath,
63 (return to b) 266
withtallermatureeucalypts and
94 21
riparian vegetation along a
104 14
creek line and BanksialKunzea
89 1 roadkill
F289 86 14 thickets separated by low
61 7 scrubby heath. Ringtails
61 27 preferred the thickets,
74 39 constructing dreys primarily in
51 17 Banksiaericifolia andtoalesser
61 42 extent in the low trees and
121 43 sturdy bushes listed in Table 2.
83 293 killed by fox Some ringtails utilized hollows
F296 110 14
in the trees near the creek line
121 28
and one individual utiUzed the
135 (a to b) 7
heath, making several nests on
135(return to a) 34
the ground.
131 7
In Ku-ring-gai Chase the
131 21
figure for usage oftree hollows
145 7
136 28 was about 33% (Augee et al.
159 21 1996). In Manly Dam Reserve
232 14 therearefew large, maturetrees
293 7 and only 3.6% of daytime
94 30 positions were in hollows. One
373 1 killed by cat animal also nested briefly in an
M317 88 28 arboreal termite mound about 5
84 (a to b) 10 m up a eucalypt tree.
84 (return to a) 4 killed by fox At any given time, a
ringtail would use several nest
wild possums in the previous study at Ku-ring-gai sites, most often within a single thicket. Around these
Chase (182 days; Augee et al. 1996). Likewise the sites the animal wouldforage overan areausually less
survival functions for these two data sets (compared than 0.2 ha with a maximum diameter of 50 m. This
inFig. 2) indicate asignificantly (p<0.01, Chi-squared foragingrangewasconsistentregardlessofthehabitat,
= 10.227) lower survival function for wild possums in
190 Proc. Linn. Soc. N.S.W., 124, 2003
B. SMITH, M. AUGEE AND S. ROSE
Table 5. Residency time of progeny that never left their natal sites. All were range, occasionally
juveniles (<600g)attimeofcollaring.Daysaremeasuredfromtimeofcollaring. establishing a new nest
m
sitemorethan50 from
Subject Female Parent Probable Male Natal Area Killed in natal the previous nest site. In
Parent Days area ormoved a few instances the
M259 F249 M244 638 K animal quickly returned
F274 F248 M246 35 K (F242, M279, F296 and
M
F278* F242 M254 27 M317 in Table 4),
M279* F242 M254 519 K
however most such
M282 F248 M246 967 K
M movements resulted in
M284 F245 M280 232
F291 F245 M280 37 K the establishment of a
M new foraging range. For
F296 F287 M264 158
M297 F298 M290 253 M example F312 remained
M307* F266 M295 293 K in the foraging area
M308* F266 M295 166 M where she was first
M
F311 F298 M290 89 caught for 90 days, then
M m
M318* UncoUared Uncollared 211 moved about 800 to a
F319* Uncollared Uncollared 83 K new foraging range,
remaining there 174
being observed for animals living along the creekline days. At that time her collar was removed since this
amongst large trees as well as in thickets. unusually large dispersal movementhad taken her out
Like many arboreal mammals (e.g. squirrels, ofthe study area.
McDonald 1984), ringtails are sedentary. At Manly Dispersal movements, resulting in the
Dam Reserve 39 of the 62 animals tracked remained establishment ofa new foraging range, were made by
withintheforagingrangewheretheywerefirstcaught. both sexes, although more males (15) did so than
One female (F273) remained in the same foraging females (8). However, the animal making the greatest
range for 582 days until being killed by a fox. number and longest dispersal moves was a female
The sedentary nature ofthe species is further (F296,Table4).Theanimalmakingthesecondgreatest
evidenced by data obtained from 14 individuals for number of moves was also a female (F289, Table 4).
whom their female parent and place of birth were The reasons for such shifts in foraging range are
known(Table5). Ofthesevenringtailsthatwerekilled unclear.
within the natal area (i.e. within 50 m of the site of InmanymammaUanspeciesthereis apattern
their birth), four had lived there for extended periods of dispersal by juveniles (McDonald 1984). Some of
from the time of being collared (293, 519, 638 and the ringtail dispersals observed in this study were by
967 days). juveniles (e.g. M264, M279, F296 and M317 inTable
Someringtailsdidmoveoutoftheirforaging 4). Howeverdispersalofjuvenileswasnotaconsistent
pattern as only 10 out of 26
(38%) ofjuveniles tracked for
more than a month made
dispersal movements. Of the
juveniles with known parents
(Table 5), three (M282, M279
cn andM259)remainedwithinthe
I- parental foraging range after
thedeath oftheparents. As can
CD
be seen from Table 3, M307
and M308 remained in
association with both parents.
One female of known parents
(F296) made frequent moves
m
^ ^ greater than 50 from the
^^^ <^e.-^.a^ ^V^ ^^" ^^ ^"^of ad- ^-%-" parental foraging area, usually
returning, until killed by a cat
Figure 5. Annual distribution ofbirths of Common Ringtail Possums at 280 m from the parental
Manly Dam Reserve. foraging area (at which time
Proc. Linn. Soc. N.S.W., 124, 2003 191
MOVEMENTS OF COMMON RINGTAIL POSSUMS
both parents were still alive). (Pseudocheirus peregrinus) in bushland near
On theotherhand, mostringtails in this study Sydney. Wildlife Research 23, 99-108.
were mutually tolerant with considerable overlap in Kaplan,E.L. andMeier,P. (1958). Nonparametricestimation
home range (Fig. 4) and foraging range (Table 2). from incomplete observations. Journal of the
American Statistical Association 53, 457-481.
Individual dreys were used by as many as 1 1 different McDonald, D. (ed.). (1984). The encyclopediaofmammals.
individuals (Table 3). Simultaneous occupancy Unwin Hyman, London
occurred (Table 3), usually by adult males with adult Newton, T. (1997). Foraging range in the common Ringtail
females and rarely two males. We did not observe Possum {Pseudocheirus peregrinus). Honours
simultaneous occupation of a drey by two adult Thesis, University ofNSW (held by the School of
females, although on one occasion the same drey was Biological, Earth and Environmental Sciences,
usedbytwoadultfemales (F242andF243)ondifferent UNSW, Sydney 2052).
nights over a period of 3 weeks We observed many Pahl,L.I. (1987). Survival, agedeterminationandpopulation
. age structure of the Common Ringtail Possum,
instances of females sharing with joeys that were too
Pseudocheirus peregrinus, in a Eucalyptus
small to radio-collar. In the only instance where we
woodlandandaLeptospermumthicketinsouthern
were able to track parents and their offspring
Victoria. Australian Journal ofZoology 35, 625-
simultaneously (F266 andM295, parentsofM307 and
639.
M308), they were found to frequently share nest sites Pollock, K.H., Winterstein, S.R., Bunck, CM. and Curtis,
(see Table 3). The degree to which this familial P.D. (1989). Survivalanalysisintelemetry studies:
tolerance continues as the juveniles reach maturity is the staggered entry design. Journal of Wildlife
unknown. Management 53, 7-15.
Although there was no evidence that any Rose, S., Augee, M.L. and Smith, B. (1994). Predation by
movements made by the ringtails were related to introduced foxes on native mammals: a study of
fox scats from Ku-ring-gai Chase National Park,
predation, the majority ofringtails in this study, as in
Sydney. In "Proceedings ofthe 1994 Conference
the study carried out earlier in Ku-ring-gai Chase
of the Australian Association of Veterinary
(Augee at al. 1996), were killed by predators, usually Conservation Biologists" (Eds A.W. English and
foxes orcats (Table 1). While it is possible that deaths G.R. Phelps), pp. 111-116. AustralianAssociation
due to "unknown predators" in the Ku-ring-gai Chase ofVeterinary Conservation Biologists: Sydney.
study mighthave been due to dogs, we feel it unlikely Smith, B. (1994). Caring for possums. Kangaroo Press,
that any deaths were due to dogs but misidentified at Sydney.
Manly Dam Reserve. Dogs are not allowed in the
reserveunlessonaleadandthisruleis activelypoliced
andwellrespectedbylocalresidents. Duringtheentire
course ofthe study we saw only one dog offthe leash.
CONCLUSION
Ringtail possums are usually sedentary,
remaining within a foraging range of approximately
50 m diameter in the Manly Dam Reserve study area.
They may on occasion move beyond this range,
althoughthereasonsforsuchlongdistancemovements
are unknown. They are probably all exploratory, but
mostresultintheestablishmentofanewforagingrange
and can be considered dispersal movements.
Presumablythenewforagingrangeprovidesimproved
feeding or reproductive resources or less competition
with conspecifics. Predation by foxes and cats was
severe throughout the study area.
REFERENCES
Augee, M.L., Smith, B. and Rose, S. (1996). Survival of
wild and hand-reared ringtail possums
192 Proc. Linn. Soc. N.S.W., 124, 2003