Sexual segregation in winter, spring dispersal and habitat use in the pheasant (Phasianus colchicus)

Sexual segregation, spring dispersal and late winter to spring habitat selection were studied in the pheasant Phasianus colchicus L. on two areas for which the proportions of different habitats were similar. On one of the sites (Damerham) hand-reared pheasants were released for shooting. On the other (Fulwell) no releasing or shooting took place.
The sex ratio of birds feeding in fields in autumn favoured males because females fed in groups within woods. Groups of birds were significantly segregated by sex during early to late winter periods, but by late March they were not. Male groups and solitary males in winter were more evenly dispersed than female groups.
At Fulwell, female winter groups consisted of regular group members (mainly adults) and transitory individuals called 'drifters' (mainly immatures).
Females in their first breeding attempt dispersed further from their winter range to their breeding range than did adult females and females dispersed further than males. Males gaining a territory for the first time moved significantly further than old territory owners. Territorial males moved less than non-territorial males between successive spring ranges.
During March June, habitat use by 33 radio-tagged females changed markedly from mixed and deciduous woodland to fields sown with winter and spring corn. The implications for management are outlined.     

Social organization in the pheasant (Phasianus colchicus): harem formation, mate selection and the role of mate guarding

Harem formation and mate selection were studied in the pheasant in order to determine the advantages of territorial harem defence polygyny to the two sexes. We investigated the factors affecting harem size and the advantage to a female in remaining with one territorial male during breeding.
Female group size declined during late March and early April as females moved from large overlapping ranges into smaller, more widely dispersed breeding ranges. The proportion of female groups accompanied by males increased during this period.
Some males had a disproportionate share of females. Settled females were monogamous but, because a female's nest was generally outside the male's territory, her home range was larger than his territory.
Harem members were usually from the same winter group. Harem size was not related to territory quality in terms of food supply or nesting cover. Females were loyal to one male in more than one year even if his territory position changed. Older, territory-owning males had more females, both adult and immature, than males with newly-established territories. Harem size was not correlated with territory size.
We conclude that the mating system of the pheasant is based on mate guarding which protects females not only from the risk of predation or injury, but also from excessive energy expenditure incurred through being chased by other males. When escorted by a territorial male, females spent three times as much time feeding, one-fifth as much time running, and one-tenth as much time alert, as they did when not guarded.     

Distribution and reproductive success of the Pied Flycatcher Ficedula hypoleuca in relation to forest patch size and vegetation characteristics; the effect of scale

We studied habitat choice, distribution and reproductive success in the Pied Flycatcher Ficedula hypoleuca in relation to the spatial structure of a fragmented forest area. Two hierarchical levels of forest habitat structure were used: (1) forest patch size (macrohabitat) and (2) vegetative structure within forest patches (microhabitat). In spring, both males and females settled preferentially in large and medium-sized forest stands (>1 ha) where breeding density was also higher than in small stands (<1 ha). Stands <5 ha were occupied later, and the proportion of unpaired males was higher there than in large stands (>5 ha). The known age distributions of breeding birds and breeding success were independent of forest patch size. Nest predation rate was not associated with stand size or nest distance from the forest edge. The preference of breeding birds for large forest patches was presumably related to the higher amount of resources (nest sites, mates, food) a large patch can offer for reproduction compared with a small patch. At the microhabitat level, territories of old males were characterized by relatively more deciduous trees that contained more invertebrate food than coniferous tree-dominated territories of yearling males. The reproductive success of old males, as measured by the number of fledged young per male, was higher than that of yearling males. This suggests that the larger body size and blacker plumage of old males possibly contributed to male dominance and that old males excluded younger males from preferred habitats through territorial behaviour. Our results suggest that habitat choice of the Pied Flycatcher was affected by both micro- and macrohabitat. On the basis of settlement pattern, density and reproductive success, the distribution of Pied Flycatchers across forest stands of different sizes followed the ideal-free distribution model, whereas at the microhabitat level, age-related unequal distribution of males followed the ideal-despotic model of Fretwell and Lucas.     

Behaviour and breeding biology of the cooperatively breeding Grey-backed Fiscal Shrike Lanius excubitorius in Kenya

Grey-backed Fiscal Shrikes Lanius excubitorius were studied over a 2j year period near Lake Naivasha, Kenya. Grey-backs are cooperative breeders, with group sizes ranging from two to II. Only one pair breeds per group, with all other group members aiding in the rearing of young. The study population ranged from 64 to 79 individuals that occurred in from 13 to 16 groups. Non-breeding helpers made up to 66% of the population, with male helpers being more numerous overall than females. The annual survival rate was 65%, with no differences detected between the survival of males and females, or of breeders and helpers. Only male helpers were observed to acquire breeding status within the natal territory. Some female helpers acquired breeding positions in territories adjacent to their natal territories. Group territorial displays occurred throughout the year but were most pronounced prior to breeding during rainy periods. Reproductive success was very low, with only 14.5% of the recorded breeding attempts leading to fledged young. Large groups (four or more birds) had greater reproductive success than small groups, but many factors other than, or in addition to, group size may have influenced this pattern. The breeding male contributed the most food to the incubating female and to the nestlings. Male helpers and the breeding female contributed more to nestlings than did female helpers. Observations on the post-fledging period indicate that socialization and establishment of dominance may be of importance in group-living species living in a restricted ecological and social setting.     

High divorce rates in Corsican blue tits: how to choose a better option in a harsh environment

We investigate which hypothesis, the “better mate hypothesis” or the “better territory hypothesis” best explains the unusually high divorce rate (59%) in a population of blue tits (Parus caeruleus) living in a sclerophyllous habitat characterised by severe environmental constraints (trophic, parasitic, climatic) on the island of Corsica, France. Using data from the breeding seasons 1985–1998 and from a brood size experiment (1990–1993) we examined the causes of divorce and their consequences on breeding performance, mate assortment and territory choice. Breeding performance had no significant effect on whether birds re‐united or divorced in the next breeding season. Re‐uniting pairs did better than divorced females and the latter improved their breeding performance compared to prior to divorce, but this was mainly due to age and territory effects. There were no differences in male performance depending on whether they re‐united or divorced. The age combination of pairs did not differ between re‐uniting and divorcing pairs, but mate assortment changed after divorce with males re‐mating more often with older partners than females. Manipulation of brood size showed a trend for birds with enlarged broods to divorce more. Pairs responded significantly to territory quality by divorcing more often in poor than in good breeding sites. Both faithful pairs and male divorcees had shorter breeding dispersal distances than female divorcees. Divorce rates were determined by the large differences in quality among breeding sites. Males, whatever their status, usually retained their previous territory whereas divorced females moved significantly longer distances and improved their breeding site. Moving to a better territory after divorce benefits only females which appear to be the choosing sex in the decision to divorce. This study strongly supports the “habitat mediated hypothesis” and we suggest that the large observed intraspecific variation in the magnitude of divorce rates in many species of birds is mostly determined by habitat characteristics.     

The Cooperative Breeding System of the Red-cockaded Woodpecker

The breeding system of the red-cockaded woodpecker is described based on data collected over six years from a population of 500 marked individuals in the Sandhills of North Carolina. Male-female pairs were the most common social unit (59%), but 30% of social units contained one or more adult helpers, and 11% consisted of solitary males. Helpers were almost exclusively male: 27% of males remained in their natal group as helpers for at least one year, whereas only four (1%) females did. Most breeding females remained as breeders in the same group from one year to the next (56%), but a surprising number (12%) moved to another group. Many movements were related to incest avoidance or mate death, but 39% involved deserting a mate, usually following successful reproduction. We suggest that females sometimes are forced from groups by immigrants or other group members. The median distance of movements by adult females was only 1.3 km. In contrast to females, no breeding males switched groups. Survival of both breeding (76%) and helper (80%) males was higher than that of breeding females (69%). Males exhibited two distinct life-history strategies. Some remained as helpers on their natal territory for one or more years, and became breeders by inheriting breeding status in the natal group (17% per year) or by replacing a deceased breeder in a nearby group (13% per year, median distance moved 1.0 km). Other males dispersed from their natal group permanently during their first year. Some of these males were floaters at age one year, others were solitary, and a few became helpers in a non-natal group, but many were breeders. In contrast to males that first functioned as helpers, those that dispersed after fledging moved long distances (median dispersal distance 4.5 km), longer even than dispersing female fledglings moved (median distance 3.2 km). The habitat saturation model of the evolution of cooperative breeding is based on selection between the two life-history strategies exhibited by male red-cockaded woodpeckers. The model therefore may be tested directly with this species. Another indication that this model is appropriate for this species is the existence of a resource (cavity trees) that might provide an ecological basis for habitat saturation.     

Reproductive success and survivorship of the Galapagos Hawk Buteo galapagoensis: potential costs and benefits of cooperative polyandry

The Galapagos Hawk Buteo galapagoensis is one of few species showing cooperative polyandry. As many as four males may mate with one female and share a territory and nest, Such groups, on average, produce more young than monogamous pairs, but on a per male basis (assuming that each male of a group has an equal chance to fertilize each young) polyandrous males produce fewer young per year than monogamous males. Territorial breeding birds show higher yearly survivorship (90%) than non-territorial, non-breeding birds (50% or less). All territorial birds seem to remain on their territories for life, and monogamous pairs actually constitute the remnants of polyandrous groups. Some potential factors producing such an unusual system are discussed. Limited breeding space and high mortality among non-territorial birds seem to work in favour of group breeding in this and other cooperative species. Polyandry may be favoured because of the reduced value of extra females in hawk breeding behaviour. Equal-status males may occur because of the lack of kinship among cooperating males and the high potential genetic cost of being a helper in a long-lived, low fecundity species. Other possible factors favouring group breeding are territory acquisition and the variable nature of the Galapagos climate.     

Group size and composition are correlated with population density in the group-territorial blue korhaan (Eupodotis caerulescens)

The blue korhaan (Eupodotis caerulescens) is a poorly known bird endemic to the grasslands of southern Africa. It lives in permanently held territories defended by groups of individuals. During 2001 and 2002, 61 transects were carried out along 544 km of roads in Mpumalanga province (South Africa) to collect data on territory density and group size and composition in this species. Habitat, altitude and topography variables were measured to evaluate their influence on population density. Average territory density was 1.56 ± 0.19 (SE) territories per 5 km and maximum densities attained 5.6 territories per 5 km. Within its area of occurrence, higher densities occurred along transects with larger proportion of short grassland (either burned or grazed) and flatter topography. Mean group size was 3.03 ± 0.11 birds (n = 119), with 87.4% of the groups having one to four birds. Most common group composition was one male and one female‐like (34.5%), followed by two male and one female‐like (17.2%) and two male and two female‐like (13.8%). Single individuals were always males, and the male/female‐like ratio peaked at a group size of three and decreased thereafter. Mean group size increased with territory density (r_s = 0.42, P = 0.007, n = 41). There were no differences in group size across habitat types. The occurrence of habitat saturation and cooperative breeding in this species could explain the observed results.     

Sex-bias and timing of natal dispersal in cooperatively breeding Puff-throated Bulbuls Alophoixus pallidus

While natal dispersal can have a significant impact on population dynamics, it is typically difficult to quantify. We investigated timing of natal dispersal of the cooperatively breeding Puff-throated Bulbul Alophoixus pallidus in a tropical evergreen forest by modelling the probability of staying in or dispersing from their natal territory whilst taking into account the effects of sex, group size, and the presence of helper(s). Birds did not disperse until the beginning of and during the breeding season following the hatching year. Dispersal was strongly female-biased both in frequency and distance: most females (95%) dispersed away from their natal territories, and of those relocated, traversed 2–7 territories. In contrast, 50% of males remained in the natal territory as helpers in their second year, while relocated dispersing males crossed 1–2 territories. Natal dispersal was not influenced by either group size or the presence of helpers. Males that fledged earlier in the breeding season exhibited higher rates of philopatry than the males that fledged later, but no correlation between fledging date and philopatry was observed in females. The probability of staying in the natal territory during the second year was 0.58 ± 0.14 SE and 0.05 ± 0.04 for males and females, respectively. These findings may add to our understanding of how natal dispersal can reflect social patterns and kin structure in cooperative breeding species from a little-studied tropical forest region.     

The social organization of the Scarlet Robin Petroica multicolor and Flame Robin P. phoenicea in southeastern Australia: a comparison between sedentary and migratory flycatchers

Scarlet Robins Petroica multicolor and Flame Robins P. phoenicea occurred sympatrically during the breeding season in southeastern Australia. Scarlet Robins that occur territories in forest habitat remained there throughout the year, while those, mostly first-year birds, that occupied territories in grassland habitat were present only during the non-breeding season. Flame Robins were present for 9 months of the year and were territorial for 6 of those months. The migratory Flame Robin did not show more intense or prolonged territorial or courtship behaviour than the sedentary Scarlet Robin, despite having to obtain territories and mates when it returned each year. It is suggested that the similarities between the two species' social organizations arise partly from high adult survivorship (70–75%) and lengthy breeding seasons (4–5 months). High adult survivorship and scarcity of suitable breeding habitat also caused intense competition for territories and mates, and appears to have led to the evolution of bright, signalling plumages among female and young male Scarlet Robins. Scarcity of females and breeding habitat may have caused delayed maturation of plumage among male Flame Robins.     

Space use in a multi-male group of the group-living lizard

The aim of the study was to determine the space use of individuals in a multi-male group of the armadillo lizard Cordylus cataphractus . Specific focus was on the adult males and females of the group, because, ultimately, the manner in which adult males and females utilize space determines the mating system. A two-dimensional (2D) grid pattern was delineated at the crevice of a free-living, multi-male group to facilitate the recording of the positions of individuals during observations. All marked individuals ( n =55) that were visible were scanned through a telescope, and their respective positions were recorded at 30-min intervals over several days during the breeding season. Arcview 3.2 Geographical Information Software was used to create a computerized replicate of the 2D grid pattern at the crevice and to depict graphically the recorded positions for each individual using a minimum convex polygon procedure. From the polygons generated by this procedure, it was clear that the space use of adult males overlapped greatly with the space use of adult females, but that there was no overlap in space-use among adult males. Space use overlapped greatly among subadults and juveniles and also among these size classes and adult males and females. Adult male C. cataphractus are territorial, defending specific sites at the crevice. The territory of each male in the group incorporated at least one female. The space use of several females overlapped with the space use of two or more males. Males were observed to mate with one or more females, and one female was observed to mate with two different males on more than one occasion. Cordylus cataphractus males display typical territorial polygyny whereas females may be promiscuous.     

Flock, pair and group living lifestyles without cooperative breeding by Australian Magpies Gymnorhina tibicen

The social behaviour of Australian Magpies Gymnorhina tibicen was studied at Linton in the Manawatu district, New Zealand, from June 1978 to November 1982. Territorial magpies defended all-purpose areas averaging 5 ha in size, and there was no correlation between territory size and the number of occupants. The mean adult survival rate was 0.85, and average annual productivity was 0.96 juveniles per breeding female. Nomadic flocks formed in the spring and foraged on open, treeless pasture. They mainly comprised 1–3-year-old magpies which did not breed. Territories were defended by monogamous pairs, and by groups ranging from three to six individuals. Some territorial groups probably originated in the flock, and may therefore have consisted of unrelated birds. Other territorial groups formed when juveniles did not disperse away from the natal territory, and were called family groups. Non-breeders did not help at the nest in any group, and there was no difference in the production of young by females breeding in group-defended territories compared with those in pair-defended territories. The opportunity to disperse into non-territorial flocks may have liberated Australian Magpies from cooperation.     

Intraspecific competition and the maintenance of monogamy in tree swallows

Intraspecific competition for access to breeding resources maylimit male mating success typically monogamous birds. We examinedthe potential for intraspecific competition to limit polygynyin tree swallows at Beaverhill Lake, Alberta, Canada. In thispopulation, polygynous males raisedmore fledglings than monogamousmales, and there was little or no cost to females from nestingpolygynously. Under these conditions one might expect polygynyto be more common than that observed(8% of males). We foundthat females were most aggressive toward conspecific intrudersearly in the breeding season. This aggression was associatedwith (1) females settling farther apart than expected underrandom settlement, (2) later settlement by secondary than bymonogamous females, and (3) no relationship between female settlementdate and male territory size instead of the negative correlationexpected if females settled randomly without competition. Earlyin the season, males also settled farther apart than expectedif they had settled randomly, and among males with two or morenest boxes on their territory, males with widely separated nestboxes were more likely to be polygynous. Monogamy is probablythe most common pairing association in this population becauseintraspecific competition for nest sites prevents most malesfrom gaining a territory with nest sites far enough apart topermit two females to breed without one female excluding theother. Females appeared to be defending an area surroundingtheir nest box to limit nest usurpation or intraspecific broodparasitism, rather than to limit any loss of male parental carefrom polygyny.     

Factors influencing seasonal and monthly changes in the group size of chital or axis deer in southern India

Chital or axis deer (Axis axis) form fluid groups that change in size temporally and in relation to habitat. Predictions of hypotheses relating animal density, rainfall, habitat structure, and breeding seasonality, to changes in chital group size were assessed simultaneously using multiple regression models of monthly data collected over a 2 yr period in Guindy National Park, in southern India. Over 2,700 detections of chital groups were made during four seasons in three habitats (forest, scrubland and grassland). In scrubland and grassland, chital group size was positively related to animal density, which increased with rainfall. This suggests that in these habitats, chital density increases in relation to food availability, and group sizes increase due to higher encounter rate and fusion of groups. The density of chital in forest was inversely related to rainfall, but positively to the number of fruiting tree species and availability of fallen litter, their forage in this habitat. There was little change in mean group size in the forest, although chital density more than doubled during the dry season and summer. Dispersion of food items or the closed nature of the forest may preclude formation of larger groups. At low densities, group sizes in all three habitats were similar. Group sizes increased with chital density in scrubland and grassland, but more rapidly in the latter—leading to a positive relationship between openness and mean group size at higher densities. It is not clear, however, that this relationship is solely because of the influence of habitat structure. The rutting index (monthly percentage of adult males in hard antler) was positively related to mean group size in forest and scrubland, probably reflecting the increase in group size due to solitary males joining with females during the rut. The fission-fusion system of group formation in chital is thus interactively influenced by several factors. Aspects that need further study, such as interannual variability, are highlighted.     

Turnover and dispersal in a Peregrine Falco peregrinus population

In south Scotland, most Peregrines returned to the same territories to breed in successive years, though a few females changed territory from one year to the next.
Annual mortality among breeding birds was at most 9% among females (or 11% in both sexes combined). There may have been considerable annual variation, however, and excluding one exceptional year out of five reduced the estimate for females to 7%. These estimates are maxima, but are still considerably lower than those obtained from ring recoveries of dead birds reported by members of the public.
Among trapped birds, four males first bred at age two years, one at three and another at four or five; two females first bred at one year, 13 at two years old and one at three. Five other females which were seen to be in first-year plumage but were not trapped, also laid eggs, and 12 other such paired females held territory but did not lay. Only one paired male held territory in first-year plumage.
In their movements between natal and breeding territories, some females moved further than males, with median distances of 83 and 58 km respectively. In addition, of birds trapped breeding in the study area, a greater proportion of the males than of the females had been born locally, despite an equal sex ratio among fledglings; this was also consistent with a greater dispersal of females. In general, Peregrines made much longer movements in their first year of life than subsequently. Movements were in any direction.     

Breeding dispersal and site-fidelity in three monogamous wader species in the Western Isles, U.K.

Adult and post-natal breeding-dispersal movements of Redshank Tringa totanus , Dunlin Calidris alpina and Ringed Plover Charadrius hiaticula were quantified in west Scotland. Data from 373 returning birds marked as breeding adults and 142 returning birds marked as chicks are presented. Unlike most previous studies, this study measured dispersal movements up to 40 km and attempted to overcome distance-related biases. For each species, adult males were significantly more nest site-faithful between years than were adult females. Likewise, first-time breeding males bred significantly closer to their natal site than did females. The settlement intensity per unit area of habitat showed marked differences between species, age classes and sex in the relative attractiveness of potential areas at different distances to settling birds. Adult dispersal was negatively and significantly related to breeding success in the previous year and positively related to capture on the nest in the previous year. Dispersal movements of adult Ringed Plover breeding on unstable cultivated habitats were significantly related to habitat quality (measured in terms of nest survival) and were always to habitat of better or equal quality.     

Cooperative nest‐defence behaviour and territory quality in a resident and socially monogamous passerine

Nest defence is a fundamental aspect of parental care in secondary cavity‐nesting birds, and predation or competition for nesting sites can involve different defensive behaviours. Because habitat quality determines breeding success, we were interested in whether breeding pairs of the Eurasian nuthatch, Sitta europaea, established in more favourable environment also manifest higher probability of cooperative behaviour during their nest‐site defence. To explore this relationship, we quantified behavioural displays of both parents and analysed activity budget ethogram data from simulated territorial intrusions performed in the chick‐feeding phase with one conspecific and two different heterospecific stimuli (dummies of nuthatch, starling and woodpecker). We found that paired individuals shared their roles during nest‐site defence to a considerable extent. Males had a significantly higher number of attacks on intruders than females, and females performed more threat displays and controls of the brood than males. Multinomial analysis of the cooperative behaviour suggested that pairs in a high‐quality territory had higher probability of reciprocal substitution of different roles towards a balance between attacks, threat displays and nest controls. Contrary to this, pairs in a low‐quality territory had less likely pairwise combinations of simultaneous behavioural states that are associated with effective nest‐site defence. The difference in response probability according to territory quality was, however, highly variable in view of the stimulus that was used in simulated territorial intrusion. Because individual roles and the complex behavioural repertoire of pairs altered in response to territory quality and potential nest‐site competitor or brood predator, our results suggest that the cooperative nest‐defence behaviour could be linked to the breeding success of this year‐round territorial species living in a heterogeneous forest habitat.     

Territory quality determines social group composition in Ethiopian wolves Canis simensis

1. We contrast the value of four different models to predict variation in territory size as follows: resource density (the ideal free distribution), population density, group size and intruder pressure (relative resource-holding potential). In the framework of the resource dispersion hypothesis, we test the effect of resource abundance and spatial variation in resource distribution on the age/sex composition of social groups. 2. We explore these drivers of territory size and group size/composition in Ethiopian wolves Canis simensis in the Bale Mountains, Ethiopia, using fine-scale distribution maps of their major prey species based on satellite-derived vegetation maps. 3. The number of adult males is correlated with territory size, while prey density, wolf population density and intruder pressure are not associated with territory size. On average, each additional adult male increases territory size by 1.18 km(2). 4. Prey abundance increases with territory size (average biomass accumulation of 6.5 kg km(-2)), and larger territories provide greater per capita access to prime foraging habitat and prey. 5. The age/sex composition of wolf packs is more closely related to territory quality than territory size. Subordinate adult females are more likely to be present in territories with greater proportions of prime giant molerat Tachyoryctes macrocephalus habitat (i.e. >80% of Web Valley territories and >20% in Sanetti/Morebawa), and more yearlings (aged 12-23 months) occur in territories with greater overall prey biomass. 6. Wolf packs with restricted access to good foraging habitat tend to defend more exclusive territories, having a lower degree of overlap with neighbouring packs. 7. The greater per capita access to prey in large groups suggests a strong evolutionary advantage of collaborative territorial defence in this species, although the relative costs of territorial expansion vs. exclusion depend upon the spatial distribution of resources. We propose a model whereby territory size is determined by the number of adult males, with the presence of subordinate females and yearlings dependent on the quality of habitat, and the abundance and distribution of prey, incorporated within territory boundaries.     

High survival rate and site fidelity in the Siberian Tit Parus cinctus, a focal species of the taiga

The Siberian Tit Parus cinctus population of Finland, and probably of the whole of Fennoscandia, has declined dramatically during this century. Understanding its population dynamics is essential for its conservation. We studied annual survival rate and dispersal distance of both breeding and fledgling Siberian Tits during 1989-97 in a moderately managed forest habitat near the southern border of its range in Kuusamo, northeastern Finland. Breeding density was low, averaging 0.51 pairs/km in a nestbox area of about 42 km². This was probably an underestimate, because we did not search for nests in natural holes. However, following its population decline, overall densities at the southern border of the range are low. The study area was, however, suitable breeding habitat as reflected by their high nesting success. Brood size at fledging averaged 7.45 young, and reproductive output was 6.16 young per breeding pair, including failed nests. Clutch size adjustment was successful among pairs producing fledglings because, on average, 92.6% of the eggs laid produced young in successful broods. Median distance between consecutive breeding attempts was 100 m for both males and females (range 0–2500 m and 0–6000 m, respectively). Natal dispersal distance was significantly longer in females than in males. We applied Cormack-Jolly-Seber modelling to estimate survival and recapture probabilities separately. Survival of breeding birds was not sex-related, averaging 0.69 annually. Some of the ringed fledglings (3.0%) were later captured as breeders in the area. This is an underestimate of local survival rate due to incomplete recapturing of breeding birds. The implications of these results with respect to the conservation status of the species are discussed.     

Whole-day follows of striped mice (Rhabdomys pumilio), a diurnal murid rodent

Understanding mammal social systems and behaviour can best be achieved through observations of individuals in their natural habitat. This can often be achieved for large mammals, but indirect methods have usually been employed for small mammals. I performed observations of the striped mouse (Rhabdomys pumilio) during the breeding season in the succulent karoo, a desert of South Africa. The open habitat and the diurnal habit of striped mice, together with the use of radio-telemetry, made it possible to collect data on activity patterns and social interactions over an entire activity period (whole-day follow). The striped mouse in the succulent karoo has been reported to form groups of one breeding male, two to four breeding females, juvenile and adult offspring of both sexes, and several litters. Accordingly, daily range size did not differ between males and females, but females spent more time foraging whereas males spent more time patrolling territory boundaries. Captive R. pumilio display biparental care, and in this study both sexes visited the nesting site during the day, possibly engaging in parental care. Mice travelled more than 900 m/day, mainly during the morning and afternoon, and rested in bushes during the hottest times of the day.