NOTE / NOTE

Age- and sex-specific settlement patterns ofchamois (Rupicapra rupicapra) offspring

A. Loison, G. Darmon, S. Cassar, J.-M. Jullien, and D. Maillard

Abstract: The social, spatial, and genetic structures of populations depend on where offspring settle and reproducein relation to their parent’s home range. However, the patterns of settlement in wild populations of large mammalsare often poorly described owing to the difficulty of monitoring mother–offspring pairs over a long period. Here,we investigated sex-specific settlement patterns in chamois (Rupicapra rupicapra (L., 1758)) based on the study of31 mother–offspring pairs. We calculated the distance between the center of the mother’s range and the center ofher offspring’s range, and tested whether this distance differed when the offspring was immature (i.e., a yearling)and after offspring sexual maturity (>2 years of age). We found no sex effect on the distance between centers ofmother and offspring ranges for yearling offsprings. However, mature sons ranged farther away from their motherthan mature daughters. Daughters appear to settle close to their mother’s home range. The distance at which adaughter settles compared with her mother’s range seems to be determined before 2 years of age. On the contrary,the distance between the center of the locations of yearling males and the center of locations of their mother doesnot predict how far away males will eventually settle when mature. We discuss the implications of these patternsfor generating female social structures, as well as population spatial and genetic structures.

Resume : Les structures sociales, spatiales et genetiques des populations dependent du lieu ou les rejetons vont s’installeret se reproduire par rapport au domaine vital de leur parents. Cependant, les patrons d’installation dans les populationssauvages de grands mammiferes sont souvent peu decrits car il est difficile de suivre les couples meres-jeunes sur uneperiode longue. Ici, nous avons etudie les patrons d’installation chez le chamois (Rupicapra rupicapra (L., 1758)) enfonction de leur sexe chez 31 couples meres-jeunes. Nous avons calcule la distance entre le centre du domaine vital dela mere et le centre de celui de son jeune et teste si la distance differait quand le jeune etait immature (jeune de 1 an)et avait atteint la maturite sexuelle (>2 ans). Nous n’avons pas trouve d’effet du sexe sur la distance entre les centresdes domaines de la mere et du jeune pour les jeunes immatures. Cependant, les fils adultes sont partis s’installer plusloin de leur mere que les filles adultes. La distance a laquelle une fille s’installe par rapport au domaine vital de samere semble determinee avant l’age de 2 ans. Au contraire, la distance entre les centres des localisations des males de 1an et le centre des localisations de la mere ne permet pas de predire la distance d’installation du fils lorsqu’il est adulte.Nous discutons de l’implication de ces patrons dans l’emergence des structures sociales femelles et des structures spatialeet genetique des populations.

Introduction

Mammal offspring are obliged to stay close to theirmother until the end of the lactation period, and often do solonger, as parental care usually extends beyond lactation(Clutton-Brock 1991). However, when the offspring growolder, the intensity of parent–offspring conflict increasesbecause of competition for food and reproduction, or becauseof the presence of new siblings (but for cooperative mammals

see Solomon and French 1997). Offspring are then facedwith the choice to remain close to their natal site (philo-patry) or to leave (dispersal). The balance between thecosts and the benefits of philopatry and dispersal tacticsmay be affected by mating system, sex or social structure,meta-population context, or local population density, aswell as a wide range of individual characteristics likebody condition or phenotype (Greenwood 1980, Matthysen2005). In polygynous species where mothers invest heavily

Received 18 September 2007. Accepted 4 March 2008. Published on the NRC Research Press Web site at cjz.nrc.ca on 16 May 2008.

A. Loison,1,2 G. Darmon, and S. Cassar. Universite de Lyon, universite Lyon 1, Centre National de la Recherche Scientifique (CNRS),Unite Mixte de Recherche (UMR) 5558, Laboratoire de Biometrie et Biologie Evolutive, 43 boulevard du 11 novembre 1918,Villeurbanne F-69622, France.J. Jullien and D. Maillard. Office National de la Chasse et de la Faune Sauvage (ONCFS), Centre National d’Etude et de RechercheAppliquee (CNERA) Faune de Montagne, 95 rue Pierre Flourens, BP74267, 34098 Montpellier CEDEX 05, France.

1Corresponding author (e-mail: anne.loison@univ-savoie.fr).2Present address: Universite de Savoie, CNRS–UMR 5553 Laboratoire d’Ecologie Alpine, 73376 Le Bourget du Lac, France.

588

Can. J. Zool. 86: 588–593 (2008) doi:10.1139/Z08-031 # 2008 NRC Canada

in offspring, females are usually more philopatric thanmales, a pattern normally accounted for by three nonexclu-sive hypotheses: (1) the resource competition hypothesis,by which females should be more philopatric owing tohigher costs for females to disperse compared with males(Greenwood 1980); (2) the local mate competition hypoth-esis, according to which males should disperse more thanfemales owing to the strong male–male competition for ac-cess to females (Johnson and Gaines 1990); and (3) the in-breeding avoidance hypothesis, which would lead the sexwith the largest variance in reproductive success to dis-perse, i.e., males in polygynous species (Moore and Ali1984; Pusey 1987). Female philopatry can lead to matrilin-eal structures, where females stay within their mother’s so-cial group or subpopulation area (red deer (Cervus elaphusL., 1758): Albon et al. 1992; Conradt et al. 1999; Soaysheep (Ovis aries L., 1758): Coulson et al. 1999; bighornsheep (Ovis canadensis Shaw, 1804): Festa-Bianchet 1986;white-tailed deer (Odocoileus virginianus (Zimmermann,1780)): Nelson and Mech 1987). Investigating the sex-specific patterns of settlement is therefore a major steptoward understanding the social, spatial, and genetic struc-tures of a population.

Indirect methods based on genetics have enabled theinvestigation of genetic spatial structure and the con-sequences of effective dispersal (e.g., Coltman et al. 2003).However, direct observations of spatial and social behaviorare required to determine the timing of dispersal and thesmall-scale consequences of philopatry on social structuresand local densities (Byers 1997; Coulson et al. 1999), aswell as increasing our understanding of the dispersal processwhich is often complex and protracted. There are, however,few observational studies on large mammals in the literaturebecause of the scarcity of wild populations in which thenatal site of individuals and kinship are known (but seeFesta-Bianchet 1986, 1991; Byers 1997; Coulson et al.1999; Clutton-Brock and Pemberton 2004). Here, weinvestigate whether male and female offspring settle closeto their mother in a chamois (Rupicapra rupicapra (L.,1758)) population based on the monitoring of individuallymarked mother–offspring pairs. We focused on sex-specifictiming of movements and sex-specific distances betweencenter of activities of mothers and center of activities ofoffspring. In a dimorphic and polygynous species such asthe chamois (Loison et al. 1999b), we expected sons tosettle farther away from their mothers than daughters,according to the inbreeding avoidance or local mate compe-tition hypotheses for males (Johnson and Gaines 1990).However, the larger distance between mother’s and off-spring’s centers of activities should be only apparent whenmales are mature (Dobson 1982). If dispersal is caused byresource competition, we should expect either no sex differ-ence in settlement patterns or a higher distance between themothers and the offspring of the sex most likely to competefor resources. In the chamois case, this would be females,which live in labile social groups (Boschi and Nievergelt2003; Crampe et al. 2007). After testing for age and sex ef-fects on how far offspring settle from their mother’s distan-ces, we discuss the small-scale consequences of philopatryversus dispersal in terms of subpopulation and group spatialstructure.

Material and methods

Study siteThe study site was the National Game Reserve (NGR) –

Les Bauges in the northern Alps (45840’N, 6813’E) situatedin France. The NGR – Les Bauges encompasses 5 205 haand is part of a typical pre-alpine massif covering a totalarea of 15 600 ha, separated from other mountain units bylarge valleys and the Annecy lake. The NGR – Les Baugesis structured around main summits separated by sharpvalleys (Fig. 1) and constitutes an isolated geographicalunit. Elevations range between 700 and 2200 m with about2% over 2000 m. One-half of the area is covered by forest.The treeline is at about 1500 m. Population size was at least1250 alpine chamois (Houssin et al. 1994; Loison et al.2006).

Chamois have been captured every year since 1985 atthree marking sites (Fig. 1) using cage-traps and drop nets,the latter since 1991. Since 1985, more than 1300 chamoishave been captured, of which 650 have been marked withvisual collars, and released, while the remaining wereexported for reintroduction purposes outside the study area.Each collar’s combination of colors and signs allows indi-viduals to be identified. Both traps and drop nets werebaited with salt. Kids were fitted with expandable collars,while adults were fitted with fixed-length collars (Richard-Hansen 1992; Loison et al. 1999c, 2006; Crampe et al.2002). Every individual was aged using horn-ring counts(Koubek and Hrabe 1983; Schroder and Von Elsner-Schack1985) and weighed. Drop nets allowed the capture of entiregroups, whereby mothers could be caught with their kid.The mother–kid relationship was assessed after capture andmarking from observation of suckling and nursing of moth-ers and kids. The monitoring of the study area was based onthe survey of seven paths on foot. As often as possible, from

Fig. 1. Map of the study area, with the location of the three mark-ing sites. The border of the Game Reserve is indicated in black.The darker the shading, the higher the elevation (300 m per shadeof gray).

Loison et al. 589

# 2008 NRC Canada

May to September and weather permitting, one or two teamsof observers would walk a path, identifying marked animalsand recording their position on a map using Lambert 2 co-ordinates with a 100 m � 100 m grid. These observationswere recorded on the open areas of the study site (50% ofthe study site).

Statistical analysesFrom 1985 to 2004, 39 kid–female pairs were individually

marked. These pairs were captured in marking sites 2 and 3(Fig. 1), which are separated by a wooded valley. Of the 39pairs, we only considered those of which offspring wereresighted at least once as yearling and (or) older individuals.We did not consider offspring <1 year of age because thekid usually stay with their mother up to their first birthday(Richard-Hansen and Campan 1992; Ruckstuhl 1999).Therefore, the location of the kid would not give any infor-mation about where the kid chose to settle compared with itsmother’s range once the mother–kid bond loosens (Richard-Hansen and Campan 1992). We therefore excluded eightpairs for which offspring were only seen as a kid. Amongthe 31 remaining pairs, 13 were mother–daughter pairs and18 were mother–son pairs. We had a total of 412 locationsfor female offspring (mean number of location per offspringwas 31.7, with a median of 7) and 137 for male offspring(mean number of location per offspring was 7.6, with amedian of 4). Most females in this population gave birth forthe first time at age 2 or 3 (Houssin et al. 1994; Loison1995). We therefore distinguished locations when the daugh-ter was a yearling from locations when the daughterwas ‡2 years old. The age at dispersal for males is not wellknown. According to the inbreeding avoidance hypothesis(see Introduction), it should occur before actual participationto reproduction, which is unlikely to be before 3 or 4 yearsof age in chamois (Von Hardenberg et al. 2000; A. Loison,G. Darmon, and J.-M. Jullien, personal observations). Indi-rect evidence from capture–mark–recapture estimates ofmale survival (Loison et al. 1999a) indicates that dispersalis most likely to occur at 2 and 3 years of age. Therefore,we also contrasted the distance between yearling sons totheir mother (before assumed dispersal age) to the distanceof ‡2-year-old sons to their mother. For the sake of simplic-ity, we used ‘‘yearling offspring’’ to designate the yearlingage stage, and ‘‘mature offspring’’ to designate thestage ‡2 years old.

We calculated the mean distance between the center ofthe mother’s location and the center of her offspring’s loca-tion when the offspring was a yearling and when the off-spring was mature. The center of the mother’s locationswas obtained by calculating the centroid of all mother’s lo-cations and the center of the offspring’s range was likewisecalculated as the centroid of offspring’s locations, for eachage class. The number of locations for most offspring wastoo low (median of 7 and 4 for daughters and sons, respec-tively; see above) to allow estimating individual home-rangesize, and therefore, to estimate for example the range over-lap between the mother’s range and her offspring’s range orto explore seasonal differences in distances between themother’s center of locations and the offspring’s center oflocations. To account for the differences in the number oflocations per offspring, we performed the statistical analyses

(see below) by weighing the estimated distance between themother’s center of locations and the offspring’s center oflocations by the number of locations per offspring (Burnhamet al. 1987). Indeed, the squared distance calculated from areference point (here considered to be the mother’s centroid)to the centroid of a sample of locations is distributed as a�2, and the variance of the estimated distance should beinversely proportional to the number of locations. Wechecked this based on offspring for which we had >10 loca-tions (for a given age class) using bootstrap and found thatthis was indeed the case. This allowed us to resume theanalyses accounting for the differences in the number oflocations for each offspring (Burnham et al. 1987).

We tested for the effects of sex and stage on the distancebetween the mother’s center of locations and the offspring’scenter of locations using linear mixed effect models. Weused mixed models to account for the fact that the same off-spring could be included in the analysis when yearling andwhen mature, and because we expect individual variabilityin the tendency to move away from their mother. We log-transformed the distances to account for the skewed distribu-tion of distances, and we weighted the mother–offspringdistance by the number of locations we had for each off-spring (see above). We therefore fitted 5 models (sex �stage, sex + stage, sex only, stage only, and constant) withoffspring identity as a random factor. Parameters for fixedeffects (sex and stage) were estimated using restrictedmaximum likelihood (REML). We used Akaike’s informa-tion criterion (AIC) for selecting the ‘‘best’’ model accord-ing to the parsimony principle (Lindsey 1999; Burnham andAnderson 2002), using maximum likelihood estimation (notREML) to obtain comparable values for the AIC. All statis-tical analyses were performed using the R software (RDevelopment Core Team 2005).

Afterwards, we compared the distance between themother’s and offspring’s centers of locations with the meandiameter of a female home range. The home range of afemale chamois is estimated to be around 100 ha in thisarea (Loison 1995), which corresponds to a circle with adiameter of 1130 m.

Results

Mean (±SD) weighted distance between the mother’s andoffspring’s centers of locations was 160.1 ± 216.2 m (range20.9–1312.7 m) for yearling daughters, 220.7 ± 255.6 m(range 63.3–1715.6 m) for yearling sons, 562.7 ± 788.1 m(range 73.7–3340.8 m) for mature daughters, and 1519.1 ±970.9 (range 44.2–4581.4 m) for mature sons. The selectedmodel included the interactive effects of both sex and age(Table 1), which indicates that sex effects differed for year-ling and mature offspring. Mother–offspring distances didnot differ per sex for yearlings (F[1,29] = 0.3, p = 0.586), butdid for mature offspring. Indeed, the center of locations ofmature sons were significantly farther away from the centerof locations of their mothers than was the center of locationsof mature daughters (F[1,16] = 4.5, p = 0.049). In addition,daughters were significantly farther away from their motherswhen mature than when yearling (F[1,16] = 29.96, p < 0.001).When calculated at the within-individual level, the weightedmean differences in distance between the centers of loca-

590 Can. J. Zool. Vol. 86, 2008

# 2008 NRC Canada

tions of yearling and mature offspring were 36.7 ± 119.5 mfor daughters (calculated on 7 pairs with both yearling andmature values) and 818.2 ± 1093.2 m for sons (calculatedon 11 pairs with both yearling and mature values). The dis-tance between mother’s and sons’ centers of location whensons were immature was not correlated with the distancecalculated when sons were mature (R2 = 0.02, t = 0.47, p =0.650, N = 11) (Fig. 2). On the contrary, the mother –mature daughter distance was significantly correlated to themother – immature daughter distance (R2 = 0.96, t = 10.61,p < 0.001, N = 7) (Fig. 2).

Only 1 daughter out of 13 (8%) monitored was actuallyobserved farther away than the mean diameter of a femalehome range, both when she was a yearling and an adult(mother–daughter pair no. 7; Fig. 2). In the case of sons, 2out of 14 yearling sons (14%) and 8 of 15 of the maturesons (53%) were farther away than the mean diameter of afemale home range.

Discussion

Based on the long-term monitoring of mother–offspringpairs, we found that offspring settlement patterns are sex-and age-dependent in chamois. Chamois is a polygynousmammal (Loison et al. 1999b) for which dispersal is usuallymale-biased (Greenwood 1980). The patterns shown hereconfirmed that males tend to move farther away from theirmother than daughters do after the immature stage (Levet etal. 1995; Loison et al. 1999b). Based on our data, inbreedingavoidance and local mate competition could be at work;however, resource competition can be ruled out, as femalesare highly philopatric, while in this social species, femalesshould have been the most sensitive to local food competi-tion (see the Introduction).

For most female offspring, home ranges were likely tooverlap with their mother’s home range. These spatial pat-terns may promote the emergence of matrilineal structures,i.e., groups of related females. However, the spatial scale atwhich these structures may occur is not yet clear. Indeed,previous studies on this population (Loison 1995) and others(Richard-Hansen 1992; Richard-Hansen and Campan 1992)failed to show preferential association of pairs of markedfemales, i.e., often seen in the same social group, where agroup is defined as individuals <50 m apart (Richard-Hansen1992). This also held true even for mother–offspring pairs

following the offspring’s independence (Richard-Hansen1992). Hence, studies of marked individual chamois reveala looser social structure than has been often described forthis species (e.g., Locati and Lovari 1991), at least in high-density populations (Richard-Hansen 1992; Loison 1995).However, the philopatry of daughters shown here (see alsoLoison et al. 1999c) implies that matrilineal structurescould be found at a larger spatial scale than that of the socialgroup (Loison 1995). Such organization (labile groups as-sociated with stable structures at a higher socio-spatialscale) has also been seen in other social ungulates whereassociations and spatial habits have been studied usingmarked individuals (e.g., pronghorn (Antilocapra ameri-cana Ord, 1815): Byers 1997; soay sheep: Coulson et al.1999; Coltman et al. 2003; Clutton-Brock and Pemberton2004; bighorn sheep: Festa-Bianchet 1986, 1991;L’Heureux et al. 1995). Recent longitudinal studies in ungu-lates suggest that females may improve their reproductivesuccess as they age, probably partly owing to increasedexperience (Weladji et al. 2006). This experience is cer-tainly partly gained by a better knowledge of the homerange and may be acquired already during the early ontog-eny (Richard Hansen 1992). The importance of experiencein improving reproductive success, and thereby fitness, cer-tainly contributes to preventing dispersal in females (Con-radt et al. 1999).

Fig. 2. Histogram of the distance between mothers and sons (above)and mothers and daughters (below) when chamois (Rupicapra rupi-capra) offspring were yearling (shaded bars) and mature (solidbars). For sons, the distance was available for both yearling andmature sons in 11 pairs, only for yearling in 3 pairs, and only formature sons in 4 pairs. For daughters, the distance was available forboth yearling and mature daughters in 7 pairs, only for yearling in 4pairs, and only for mature sons in 2 pairs. The thick horizontal linecorresponds to the diameter of a mean adult female home range(1130 m).

Table 1. Models and model selection for explaining chamois(Rupicapra rupicapra) mother–offspring distance.

Model df AIC �AICSex + stage + sex � stage + (ID) 6 697.48 0Sex + stage + (ID) 5 717.22 19.74Sex + (ID) 4 992.84 295.36Stage + (ID) 4 711.17 13.69Constant + (ID) 3 992.17 224.69Sex + stage + sex � stage 5 1571.14 873.66

Note: Sex and stage (yearling vs. mature offspring) are factors. IDrefers to the offspring’s identity and was accounted for as a randomfactor. AIC denotes Akaike’s information criterion used for model se-lection. �AIC compared models with the selected models (i.e., themodels with the lowest AIC values).

Loison et al. 591

# 2008 NRC Canada

Although observations of adult males suggest that theyhave a larger home range than females in our study site(Loison 1995), we do not have a reliable estimate of thesize of their home range. Therefore, the comparison of thedistance between the mother’s and her offspring’s centers oflocations with the mean diameter of a female home rangecannot reliably be interpreted in terms of the overlapbetween the home ranges of mother and son. However, ourdata clearly supported a higher trend for males leaving theirnatal range, especially after 2 years of age, which supportthe inbreeding avoidance hypothesis (Pusey 1987) but couldalso be explained by the local mate competition hypothesis.Social behaviors of mothers and sons have not been studiedbefore in chamois using marked individuals. Males appear tochoose where to settle later than females. The age at whichthey settle should be investigated further in relation to theactual age of male participation to the rut. In addition,whether males use different ranges during the mating seasoncompared with the rest of the year should also be exploredto better understand the connection between settlementpatterns and inbreeding avoidance. Surveys should thereforespan longer than the summer period to access seasonalvariation in range use. Differences between sexes in thetiming of settlement have rarely been investigated in thewild in ungulates, but sex differences in distances and asso-ciation patterns between mother and offspring could start asearly as the first weeks of life (Schwede et al. 1994).

Sexual segregation occurs at the population level,whereby adult males are not often seen within groups offemales (Loison 1995; Bonenfant et al. 2007). Familygroups often consist of females, kids, yearlings, and imma-ture males (Gerard and Richard-Hansen 1992; Bonenfant etal. 2007). In addition to this social segregation, which doesnot require sex-biased dispersal, our data suggest that malesin a given area are less likely to be closely related to thefemales than females are to other females (for similar pat-terns in Soay sheep see Coltman et al. 2003). We still lackdata sets for large mammals to better understand whyindividuals choose to settle where they do and what triggersdispersal (Matthysen 2005). To disentangle these processes,the long-term monitoring of known mother–offspring pairsis required and should be complemented with studies ofgenetic structures (Rousset 2001).

AcknowledgementsThis study has been possible because of the long-lasting

efforts of the National Hunting and Wildlife Office(ONCFS) to catch mother–kid pairs, with the help of manyvolunteers. We thank them all, as well as the many studentsperforming long hours of observation of marked individualsin the field. We are also grateful to J.-M. Gaillard, N.G.Yoccoz, and M. Hewison who kindly provided useful inputsand comments.

ReferencesAlbon, S.D., Staines, H.J., Guinness, F.E., and Clutton-Brock, T.H.

1992. Density-dependent changes in the spacing behaviour offemale kin in red deer. J. Anim. Ecol. 61: 131–137. doi:10.2307/5516.

Bonenfant, C., Gaillard, J.-M., Dray, S., Loison, A., Royer, M., andChessel, D. 2007. Testing sexual segregation and aggregation:

old ways are best. Ecology, 88: 3202–3208. doi:10.1890/07-0129.1. PMID:18229854.

Boschi, C., and Nievergelt, B. 2003. The spatial patterns of Alpinechamois (Rupicapra rupicapra rupicapra) and their influence onpopulations dynamics in the Swiss National Park. Mamm. Biol.68: 16–30. doi:10.1078/1616-5047-1610058.

Burnham, K.P., and Anderson, D.R. 2002. Model selection andinference: a practical information–theoretic approach. 2nd ed.Springer-Verlag, New York.

Burnham, K.P., Anderson, D.R., White, G.C., Brownie, C., andPollock, K.H. 1987. Design and analysis methods for fishsurvival experiments based on release–capture. Am. Fish. Soc.Monogr. No. 5.

Byers, J.A. 1997. American pronghorn. University of ChicagoPress, Chicago.

Clutton-Brock, T. 1991. The evolution of parental care. PrincetonUniversity Press, Princeton, N.J.

Clutton-Brock, T., and Pemberton, J. 2004. Soay sheep: dynamicsand selection in an island population. Cambridge UniversityPress, Cambridge, UK.

Coltman, D.W., Pilkington, J., and Pemberton, J.M. 2003.Fine-scale genetic structure in a free-living ungulate popula-tion. Mol. Ecol. 12: 733–742. doi:10.1046/j.1365-294X.2003.01762.x. PMID:12675828.

Conradt, L., Clutton-Brock, T.H., and Guinness, F.E. 1999. Therelationship between habitat choice and lifetime reproductivesuccess in female red deer. Oecologia (Berl.), 120: 218–224.doi:10.1007/s004420050851.

Coulson, T., Albon, S., Pilkington, J., and Clutton-Brock, T. 1999.Small-scale spatial dynamics in a fluctuating ungulate population.J. Anim. Ecol. 68: 658–671. doi:10.1046/j.1365-2656.1999.00298.x.

Crampe, J.P., Gaillard, J.-M., and Loison, A. 2002. L’enneigementhivernal : un facteur de variation du recrutement chez l’isard(Rupicapra pyrenaica pyrenaica). Can. J. Zool. 80: 1306–1312.doi:10.1139/z02-092.

Crampe, J.P., Bon, R., Gerard, J.F., Serrano, E., Caens, P.,Florence, E., and Gonzalez, G. 2007. Site fidelity, migratorybehaviour and spatial organisation of female izards (Rupicaprapyrenaica) in the Pyrenees National Park, France. Can. J. Zool.85: 16–25. doi:10.1139/Z06-185.

Dobson, F.S. 1982. Competition for mates and predominantjuvenile dispersal in mammals. Anim. Behav. 30: 1183–1192.doi:10.1016/S0003-3472(82)80209-1.

Festa-Bianchet, M. 1986. Seasonal dispersion of overlappingmountain sheep ewe groups. J. Wildl. Manag. 50: 325–330.doi:10.2307/3801922.

Festa-Bianchet, M. 1991. The social system of bighorn sheep:grouping patterns, kinship and female dominance rank. Anim.Behav. 42: 71–82. doi:10.1016/S0003-3472(05)80607-4.

Gerard, J.F., and Richard-Hansen, C. 1992. Social affinities asthe basis of the social organization of a Pyrenean chamois(Rupicapra pyrenaica) population in an open mountain range.Behav. Process. 28: 111–122. doi:10.1016/0376-6357(92)90053-G.

Greenwood, P.J. 1980. Mating system, philopatry and dispersal inbirds and mammals. Anim. Behav. 28: 1140–1162. doi:10.1016/S0003-3472(80)80103-5.

Houssin, H., Loison, A., Gaillard, J.-M., and Jullien, J.-M. 1994.Validite d’une methode d’estimation des effectifs de chamoisdans un massif des Prealpes du nord. Gibier Faune Sauvage, 11:287–298.

Johnson, M.L., and Gaines, M.S. 1990. Evolution of dispersal:theoretical models and empirical tests using birds and mammals.

592 Can. J. Zool. Vol. 86, 2008

# 2008 NRC Canada

Annu. Rev. Ecol. Syst. 21: 449–480. doi:10.1146/annurev.es.21.110190.002313.

Koubek, P., and Hrabe, V. 1983. Dynamics of horn growth in theJesenik mountain populations of chamois, Rupicapra rupicaprarupicapra. Folia Zool. (Brno), 32: 97–111.

Levet, M., Appolinaire, J., Catusse, M., and Thion, N. 1995.Elements demographiques, comportement spatial et dispersiond’une population d’isards (Rupicapra pyrenaica pyrenaica) enphase de colonisation. Mammalia, 59: 489–500.

L’Heureux, N., Lucherini, M., Festa-Bianchet, M., and Jorgenson,J.T. 1995. Density-dependent mother–yearling association inbighorn sheep. Anim. Behav. 49: 901–910. doi:10.1006/anbe.1995.0122.

Lindsey, J.K. 1999. Models for repeated measurements. OxfordUniversity Press, Oxford.

Locati, M., and Lovari, S. 1991. Clues for dominance in femalechamois: age, weight or horn size. Aggress. Behav. 17: 11–15.

Loison, A. 1995. Approches intra- et inter-specifiques de la dynami-que des populations : l’exemple du chamois. Ph.D. thesis, Univer-sity of Lyon I, Lyon, France.

Loison, A., Festa-Bianchet, M., Gaillard, J.-M., and Jorgenson, J.T.1999a. Age-specific survival in five populations of ungulates:evidence for senescence. Ecology, 80: 2539–2554.

Loison, A., Gaillard, J.-M., Pelabon, C., and Yoccoz, N.-G. 1999b.What factors shape sexual size dimorphism in ruminants? Evol.Ecol. Res. 1: 611–633.

Loison, A., Jullien, J.M., and Menaut, P. 1999c. Subpopulationstructure and dispersal in two populations of chamois (Rupi-capra sp.). J. Mammal. 80: 620–632. doi:10.2307/1383306.

Loison, A., Appolinaire, J., Jullien, J.M., and Dubray, D. 2006.How reliable are population counts to detect trends in populationsize of chamois? Wildl. Biol. 12: 77–88. doi:10.2981/0909-6396(2006)12[77:HRATCT]2.0.CO;2.

Matthysen, E. 2005. Density-dependent dispersal in birds andmammals. Ecography, 28: 403–416. doi:10.1111/j.0906-7590.2005.04073.x.

Moore, J., and Ali, R. 1984. Are dispersal and inbreeding avoidancerelated? Behaviour, 32: 94–112.

Nelson, M.E., and Mech, L.D. 1987. Demes within a northeastern

Minnesota deer population. In Mammalian dispersal patterns.Edited by B.D. Chepko-Sade and Z.T. Halpin. University ofChicago Press, Chicago. pp. 27–40.

Pusey, A.E. 1987. Sex-biased dispersal and inbreeding avoidance inbirds and mammals. Trends Ecol. Evol. 2: 295–299. doi:10.1016/0169-5347(87)90081-4.

R Development Core Team. 2005. R: A language and environmentfor statistical computing. R Foundation for Statistical Computing,Vienna, Austria.

Richard-Hansen, C. 1992. Associations between individually markedisards (Rupicapra pyrenaica pyrenaica): seasonal and inter-annual variations. In Ongules – Ungulates 91. SFEPM–IRGM,Paris, Toulouse, France. pp. 299–304.

Richard-Hansen, C., and Campan, R. 1992. Social environment ofisard kids, Rupicapra pyrenaica p., during their ontogeny. Z.Saeugetierkd. 57: 351–363.

Rousset, F. 2001. Genetic approaches to the estimation of dispersalrates. In Dispersal. Oxford University Press, New York.pp. 18–28.

Ruckstuhl, K.E., and Ingold, P. 1999. Aspects of mother–kid beha-vior in Alpine chamois, Rupicapra rupicapra. Z. Saeugetierkd.64: 76–84.

Schroder, W., and Von Elsner-Schack, I. 1985. Correct age deter-mination in chamois. In The biology and management of moun-tain ungulates. Croom Helm, London. pp. 65–70.

Schwede, G., Hendrichs, H., and Wemmer, C. 1994. Early mother–young relations in white tailed deer. J. Mammal. 75: 438–445.doi:10.2307/1382565.

Solomon, N.G., and French, J.A. 1997. Cooperative breeding inmammals. University of Cambridge Press, Cambridge, UK.

Von Hardenberg, A., Bassano, B., Peracino, A., and Lovari, S.2000. Male alpine chamois occupy territories at hotspots beforethe mating season. Ethology, 106: 617–630. doi:10.1046/j.1439-0310.2000.00579.x.

Weladji, R., Gaillard, J.-M., Yoccoz, N.G., Holand, O., Mysterud,A., Loison, A., Nieminen, M., and Stenseth, N.C. 2006. Goodreindeer mothers live longer and become better in raising off-spring. Proc. R. Soc. Lond. B Biol. Sci. 273: 1239–1244.doi:10.1098/rspb.2005.3393.

Loison et al. 593

# 2008 NRC Canada