The Social System of a Communal Breeder,the Bay-winged Cowbird Molothrus badius

Molothrus badius (bay-winged cowbird), an icterine blackbird with cooperative breeding, shares behavioural and ecological characteristics with other communal nesters: it is sedentary, has a high annual survival rate (76.2%) and a strong nest-site tenacity (mean breeding dispersal of 41.9 and 89.4 m for males and females). Behavioural data, including collective agonistic displays, suggest group territoriality. Before egg hatching most breeders occurred as single pairs showing territorial behaviour (82% of nests), and nesting was usually solitary (distances to nearest nests of 25–103 m). Most breeders were apparently monogamous, with a 2.5% incidence of extrapair copulations in the territory during clutch formation. During the nestling stage one to four helpers occurred at 95% of M. badius nests. Most helpers were 1–2 years old, but older breeding adults (mostly males) that failed to rear their own offspring helped at the end of the season. The number of helpers increased (up to 4) with nestling age. Helpers were also recruited during the postfledging period, and group size reached up to 10 adults at this stage. Helpers mobbed predators and brood parasites, and provided 35% of the nestling food. Provisioning rate was positively and significantly correlated with number of helpers, although age of nestlings was the best predictor of overall food delivery rate. The helping system was almost obligate and productivity comparisons between nests with/without helpers are not possible. Data suggest that helpers increased the breeding success per nest. The correlation between the provisioning rates of parents and helpers was negative but non-significant. In 18% of nests 3 to 4 individuals were present before the nestling period, including cases of apparently polyandrous trios and one case of joint nesting by two pairs. Within Brown 's (1987) categories of social organization M. badius is mainly group territorial with plural nesting. Habitat requirements of M. badius are wide and nest sites do not appear to limit breeding. Kinship plays a role in the social system, as 9 of 12 helpers marked as nestlings helped their parents.     

Extrapair paternity, inclusive fitness, and within-group benefits of helping in western bluebirds

In central coastal California, USA, 3–16% of western bluebird ( Sialia mexicana ) pairs have adult male helpers at the nest. Demographic data on a colour-ringed population over a 13-year period indicate that helpers gain a small indirect fitness benefit through increases in the number of young fledged from nests of close kin. A small proportion of adult helpers (16%) that were able to breed and help simultaneously had higher annual inclusive fitness than males that only bred. These males comprised such a minor proportion of helpers that the mean fitness of helpers was still lower than the mean fitness of independent breeders. We used DNA fingerprinting to determine whether extrapair fertilizations alter within-group benefits enough to tip the balance in favour of helping behaviour. Overall, 19% of 207 offspring were sired by males other than their social father and extrapair fertilizations occurred in 45% of 51 nests. Intraspecific brood parasitism was rare so that mean mother-nestling relatedness approximated the expected value of 0.5. Extrapair paternity reduced putative father-offspring relatedness to 0.38. Mean helper-nestling relatedness was 0.41 for helpers assisting one or both parents and 0.28 for helpers aiding their brothers. Helpers rarely sired offspring in the nests at which they helped. Helping was not conditional on paternity and helpers were not significantly more closely related to offspring in their parents' nests than to offspring in their own nests. Although helpers may derive extracurricular benefits if helping increases their own or their father's opportunities for extrapair fertilizations, within-nest inclusive fitness benefits of helping do not compensate males for failing to breed. Breeding failure and constraints on breeding are the most likely explanations for why most helpers help.     

Fitness consequences of helping behavior in the western bluebird

We examined the fitness consequences of helping behavior inthe western bluebird (Sialia mexicana) at Hastings Reservationin Carmel Valley, California, USA, and tested hypotheses forhow helpers benefit from engaging in alloparental behavior.Both juvenile and adult western bluebirds occasionally helpat the nest During a 12 year period, all adult helpers and mostjuvenile helpers were male. Helpers usually fed at nests ofboth their parents and rarely helped when only one parent waspresent. The frequency of pairs with adult helpers was only7%, but nearly one-third of adult males helped among those withboth parents on the study area. At least 28% were breeders whosenests failed. The propensity to help appears to depend uponparental survival, male philopatry, and the breeding successof potential helpers. Feeding rates were not increased at nestswith juvenile helpers, apparendy because breeding males reducedtheir feeding rates. In contrast, adult helpers increased theoverall rates of food delivery to the nest in spite of a reductionin the number of feeding trips made by both male and femaleparents. Helpers did not derive any obvious direct fitness benefitsfrom helping, but they had greater indirect fitness than nonhelpersdue to increases in nestling growth rates and fledging successat their parents' nests. Helpers fledged fewer offspring intheir first nests than did nonhelpers, suggesting that theywere birds with reduced reproductive potential. Although wehave not yet measured the effect of extrapair fertilizationson the fitness benefits of helping, we calculated the differencein fitness between helpers and nonhelpers as a function of thepotential helper's paternity when breeding independently andhis father's paternity in the nest at which he might help. Inconjunction with constraints on breeding and indirect fitnessbenefits, we predict that relatedness of males to the youngin their own as well as their parents' nests will influencehelping behavior in western bluebirds.     

An Experimental Study of Chick Provisioning in the Cooperatively Breeding Acorn Woodpecker

Acorn woodpeckers (Melanerpes formicivorus) are cooperative breeders in which groups consist of a variable number of cobreeding males, joint‐nesting females, and non‐breeding helpers of both sexes that are offspring from prior nests. We temporarily manipulated brood size of nests to determine the feeding response of birds in relation to their status (breeder or non‐breeding helper) and sex. All categories of birds responded similarly to brood size increases, adjusting their feeding rate upwards so as to maintain approximately the same per‐nestling feeding rate. Breeders, however, exhibited more flexibility with respect to brood size reductions, decreasing their feeding rate while helpers did not. This suggests that the ‘feeding rules’ of helpers are less flexible than those of breeders, a result not previously detected in other cooperative breeders that have been studied to date. Particularly surprising was the finding that helpers maintain their feeding rates when brood demand is decreased rather than when it was increased, suggesting that the flexibility they exhibit is not a result of birds using the opportunity afforded by reduced brood demand to engage in other less cooperative activities.     

Floaters as intraspecific brood parasites in the grey starling Sturnus cineraceus

The breeding season of the grey starling Sturnus cineraceus is divided into two periods: the early and late breeding season. The birds that breed in each season are referred to as early and late breeders, respectively. In this study, the late breeders mainly consisted of new immigrants that did not breed in the early season. This suggested that these new immigrants were probably floaters in the early breeding season. Because intraspecific brood parasitism occurred frequently, it is possible that the parasites were floaters without nesting boxes. To check for the presence of floaters, two field experiments were conducted and floaters were captured with traps. With additional nesting boxes provided during the breeding season, all new boxes were quickly occupied by floaters from the period of incubation to hatching in the early breeding season, but were not occupied by floaters during the egg laying period of the late breeding season. The addition of boxes before the start of the breeding season significantly decreased the parasitic rate and number of parasitic eggs per nest. There was a positive correlation between the relative occupancy of nesting boxes and the parasitic rate. The removal of boxes again increased the parasitic rate. As for the capture of floaters with traps, the number of trapped birds per day was also related to the relative occupancy of nesting boxes. The floaters trapped between incubation and nesting periods of early breeders became the late breeders. Judging from these results, many floaters were present from the incubation to hatching periods of early breeders, and were probably intraspecific brood parasites.     

COOPERATIVE BREEDING OF THE NORTHWESTERN CROW CORVUS CAURINUS IN BRITISH COLUMBIA

The behaviour of helpers at nests of Northwestern Crows was studied on Mandarte Island and Mitlenatch Island, British Columbia. Not all nests had a helper and there was only one helper per nest. Helpers participated in varying degrees in the defence of the territory and nest, feeding of the nestlings and fledglings and they cached food on the territory. Adult males fed helpers, and helpers obtained most of their food on the adults' territory. Adults with helpers laid larger clutches and produced more fledglings per nest than adults without helpers. It is suggested that cooperative breeding in the Northwestern Crow is of recent origin.     

Intraspecific brood parasitism: a strategy for floating females in the European starling

In many bird species, there is a floating population of females that are excluded from breeding because of competition for limited breeding resources. Female floaters may enhance their reproductive success by engaging in intraspecific brood parasitism. We studied female floaters in a population of European starlings, Sturnus vulgaris, in order to determine their identity and potential parasitic behaviour. Females were caught after being attracted to nestboxes with artificial nests during 1993-1995. None of the females was known to have a nest of her own at capture but 47% of the females either laid an egg in the nest or carried a fully developed egg within the reproductive tract, indicating that they were intraspecific brood parasites. The floating females were significantly younger and smaller than breeding females. Of 13 females equipped with radiotransmitters and followed daily, all but one started a breeding attempt of their own after 3-8 days and the majority settled as secondary females or mated with males where the original female had disappeared. This suggests that females that are unable to compete successfully for nest sites or males early in the breeding season may use intraspecific brood parasitism to enhance reproductive success during the period that they are constrained from breeding. The importance of settling rapidly because of a seasonal decline in reproductive success may also promote the evolution of intraspecific brood parasitism in the starling. The relative reproductive success of combining egg dumping with breeding compared with traditional breeding will depend on the costs of delaying breeding as well as the probability of finding a mate later in the breeding season. Copyright 1999 The Association for the Study of Animal Behaviour.     

Helpers increase long-term but not short-term productivity in cooperatively breeding long-tailed tits

Helpers at the nest in the cooperative breeding system of long-tailedtits Aegithalos caudatus exhibit kin preference in their helpingbehavior. The aim of this study was to use multivariate analysesto investigate whether helpers accrue indirect fitness benefitsthrough their cooperation by increasing the productivity ofrelatives. All birds started each season breeding independentlyin pairs, but birds that failed in their own breeding attemptoften redirected their care to help another pair provision theiroffspring. About half of all broods had one or more helpers,86% of which were male. Provisioning rates increased and therewas a corresponding increase in the mass of nestlings withinbroods as the number of helpers increased. Helpers had no significantshort-term effect on productivity because nest predation, nestlingsurvival, and brood size were unaffected by the presence ofhelpers. However, in the long term helpers had a highly significanteffect on the recruitment of fledglings, the positive effectof helpers being linear within the range of helper numbers thatwe observed. We found no evidence to suggest that these resultswere confounded by the effects of individual or habitat quality.We conclude that long-tailed tits accrue indirect fitness benefitsby helping kin. Nevertheless, the inclusive fitness benefitfrom helping is substantially lower than that of independentbreeding, showing that helpers are making the best of a badjob.     

Helper effects in the azure‐winged magpie Cyanopica cyana in relation to highly‐clumped nesting pattern and high frequency of conspecific nest‐raiding

In avian cooperative breeding systems, many benefits obtained by social pairs from the presence of helpers have been uncovered. However, until now, the factors that determine the type of assistance helpers provide and the responses of social pairs have not been well illustrated. We examined the contribution of helpers to cooperative groups and the relevant responses of dominant pairs in the azure‐winged magpie Cyanapica cyana which breeds on the Tibetan Plateau. We used the capture–mark–recapture method to identify helpers. Results showed that helpers were mostly the yearling sons of dominant pairs. They mainly contributed to the cooperative group in three ways, courtship‐feeding the incubation female, provisioning the brood, and defending the nest. For responses of dominant pairs, we unexpectedly found that clutch size was not influenced by the presence of helpers at the nest. However, cooperative groups had higher brood feeding rates than biparental nests and their feeding pattern also differed to that of the latter. Consequently, nestlings in cooperative groups had larger fledging body mass than that in biparental nests. By examining reasons for nest failure, we revealed that conspecific nest‐raiding contributed to more nest failure than any other natural predators. Because of the contribution of helpers in defending against both predators and conspecific nest‐raiders, cooperative groups had higher survival rate than biparental nests. Thus, our findings suggest that in a highly‐clumped nesting pattern, factors concerning the risk of nest predation, rather than that influencing food supply, play an important role in determining helper effects and responses of aided dominant pairs.     

Flexible Helping Behaviour in the Azure-Winged Magpie

Helping to rear the offspring of others may be a way for younger birds to gain access to future reproduction especially when turnover of breeding opportunities is low. However, this explanation is not applicable to cases where adults also help, or when roles shift between helpers and breeders. Over a period of 6-yr, we studied a marked population of azure-winged Magpie (Cyanopica cyanus) breeding in a non-territorial, colonial system. Magpies bred in a highly flexible cooperative system, in which individuals helped at different stages of the breeding cycle, including nest building, feeding the incubating female and feeding the young and removing the faecal sacs. On average, 50% of hatched nests were assisted by helpers-at-the-nest, and nest success appeared to be positively related to the presence of helpers. Helpers were predominantly males. Although juveniles were more likely to help, both juvenile and adult birds helped. Individual birds behaved as helpers either as a first-option or after having attempted their own breeding (second-option helpers). An individual helper may assist more than one nest during the same breeding season and in different breeding seasons. Reversals between breeder and helper roles were common in both directions, within a breeding season and between years. Helping behaviour is an option for almost any member of the colony. Therefore, hypotheses related to the enhancement of future breeding opportunities for juveniles can be discarded as general explanation of helping in this species. Although the decision to help appeared to be influenced by proximal environmental conditions hindering successful breeding, the associated benefits of helping as opposed to simply recovering for future reproduction, especially for former breeders, deserve further study.     

Sexual aggression by intruders in hooded crow <Emphasis Type="Italic">Corvus cornix</Emphasis>

The hooded crow Corvus cornix is a west Palaearctic, solitary nesting, monogamous corvid. In the breeding season, populations are characterized by a social organization wherein breeding pairs are territorial and non-breeding individuals, called floaters, live in flocks. During a study of the breeding ecology of the hooded crow, conducted in a protected flooded area, we monitored nests with video cameras. We recorded two separate incidents when intruders attacked a female at the nest. We believe that she remained in the nest in order to prevent the strangers cannibalizing the nestlings by mantling over the brood. The spatio-temporal occurrence of these attacks suggests that the observed behaviour is intraspecific sexual aggression wherein non-breeding males mounted an immobilized female.     

Intruders in Nests of the Spotless Starling: Prospecting for Public Information or for Immediate Nesting Resources?

The prospective behaviour for nests by conspecific intruders may be a strategy to gather public information for future reproduction or to secure resources for immediate reproduction. Although the relationship between the sex, age and breeding experience of intruders and the sex and age of residents may be crucial for understanding the significance of nest‐prospecting behaviour, a precise determination of these traits has rarely been addressed in field studies. In a free‐ranging population of spotless starlings ( Sturnus unicolor), inexperienced birds were the predominant intruders. The ratio of male‐to‐female intruders was higher among birds without previous breeding experience, although our results did not allow us to determine whether more inexperienced males or females intruded nests. The average annual rate of intrusion of either sex was strongly correlated with the number of fledglings produced in the study colony the previous year, which seems to indicate that the inexperienced intruders were, in general, yearlings. The proportion of the sexes among the intruders in each study year was correlated with the average age of male owners but not with the age of female owners. This result suggests that the presence of intruding males in the nests was affected by an increased opportunity to find vacancies in nesting territories as resident males became older. This finding supports the hypothesis that, in most cases, birds visited nests to obtain personal information about nesting resources. However, the intrusion rates were higher when there were nestlings than during the incubation period, which suggests that collecting public information was also involved in the intruding behaviour. Both sexes regularly attacked intruders, which implies that the intruders inflicted some kind of cost on the owners. Female floaters were more frequently chased, probably because they regularly lay parasitically in conspecific nests.     

Brood desertion and polygamous breeding in the Kentish Plover Charadrius alexandrinus

In the Kentish Plover Charadrius alexandrinus one of the adults, typically the female, deserts the brood when the chicks are a few days old. Once parental care is terminated, adults may initiate a second nesting attempt if sufficient time remains within the season. For these nests, individuals pair with different mates from those of the first nesting attempt, thus becoming sequentially polygamous. In a small population of Kentish Plovers in Fuente de Piedra lake (southern Spain), the duration of biparental care of broods was longer than in other localities. It also showed considerable variation between years that was evidently related to Gull-billed Tern Gelochelidon nilotica predation pressure on the chicks. There was year-to-year variation in the number of polygamous matings. Both the duration of the breeding season and nesting success in the first half of the season limited the occurrence of polygamy. Despite females deserting broods earlier than males, the interval between the first and second nesting of polyandrous females and polygynous males was similar. The interval was not affected by the body condition of females after the first nesting attempt, nor by problems related to egg formation ability, but was probably due to the availability of potential mates. More females than males initiated second nests, suggesting that polygamous opportunities were more limited for males than for females. In terms of delayed breeding, reduced survivorship or reduced breeding opportunities in years following polygamous breeding, polygamous individuals did not have greater costs than non-polygamous ones. Females with second nests did not seem to be selective in mate choice, mating with any available male. Mates for second nests may therefore be of lower quality than those for first nests, as judged by male plumage characteristics. Clutch sizes and egg characteristics of polyandrous females were similar in first and second nests. Nest success of second nests was only 40% of that of first ones, with nest desertion accounting for 60% of the losses. As the costs of polygamy are apparently low and as breeding success is very variable among years, polygamous breeding of the long-lived Kentish Plover may be an important breeding strategy with which to increase individual lifetime reproductive success.     

Breeding ecology of the Eastern Great Reed Warbler Acrocephalus arundinaceus orientalis at Lake Kasumigaura,central Japan

CapsuleTwo populations of the Eastern Great Reed Warblers, one close to settlements and one far away, differed mainly in nest losses which were higher at the latter site.

Aims To compare the breeding ecology of two Japanese populations, and with breeding data from Polish sites.

Methods We studied two sites in 1996. The Seimei site comprises a natural reed-bed (Phragmites australis) (2.0 ha) c. 2 km from residential areas. The Sakura site occurs as smaller reed-bed (0.8 ha) close to residential areas. Field study comprised mainly nest searching and nest monitoring.

Results Breeding density, nest height, number of stems supporting nest, clutch size and brood size were not significantly different between sites. The proportion of nests built on reed stems standing in the water (60%) was significantly higher at the Seimei site (P < 0.001), and the warblers in this habitat experienced significantly higher nesting failure (P < 0.05). Predation was a principal cause of failure at both sites. Significantly more nests suffered from predation at Seimei (53%) than at Sakura (16%). Breeding density was higher at both sites compared with European populations but it fell within ranges of other Japanese populations. Mean first-egg date of first brood does not differ between our sites and Polish ones.

Conclusion The differences between the two Japanese populations and between Japanese and Polish populations were relatively small and were seen mainly in nest losses, breeding density and proportion of nests built over water.     

Helper contributions in the cooperatively breeding laughing kookaburra: feeding young is no laughing matter

I studied the contributions of individuals to incubation and nestling feeding in a population of cooperatively breeding laughing kookaburras, Dacelo novaeguineae. In most cooperatively breeding birds where nest success is limited by nestling starvation, related helpers increase the overall level of provisioning to the nest, thus boosting the production of nondescendent kin. However, although partial brood loss is the largest cause of lost productivity in kookaburra nests, additional helpers failed to increase overall provisioning. Instead, all group members, but especially helpers, reduced their feeding contributions as group size increased. Breeders and helpers reduced the size of prey delivered, and helpers also reduced the number of feeding visits. An important benefit of helping in kookaburras may be to allow all group members to reduce their effort. Within groups, contributions to care depended on status, sex, group size and the brood size. Breeding males delivered the most food. Breeding females provisioned less than their partner, but their effort was comparable to that of male helpers. Female helpers contributed the least food. Incubation effort followed similar patterns. The relatedness of helpers to the brood had no impact on their provisioning. Across all group sizes, helpers generally brought larger items to the nest than breeders. Copyright 2000 The Association for the Study of Animal Behaviour.     

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.     

Group structure, mating system and extra-group paternity in the co-operatively breeding White-breasted Thrasher Ramphocinclus brachyurus

Avian co-operative breeders show a diverse range of social and reproductive systems. Here we combined microsatellite genotyping with field observations over three consecutive breeding seasons to investigate the social structure and mating system of the White-breasted Thrasher Ramphocinclus brachyurus . Co-operative breeding was facultative in this species, with approximately one-third of nests having helpers. Breeding groups comprised a pair of breeding adults and up to three helpers of either sex. Within co-operative groups, age was associated with parentage in both sexes. Helpers were retained offspring and either rarely or never achieved parentage in current broods. There was no evidence of egg dumping and a relatively small percentage of chicks (7.5%, n  = 67) were fathered by males from outside the co-operative group. The White-breasted Thrasher is a globally Endangered species with a very small and declining population. A captive breeding programme for this species is not recommended at present, but may become necessary in the future, and any such programme should take account of our findings regarding breeding behaviour and group structure.     

Cichlids do not adjust reproductive skew to the availability of independent breeding options

Helpers in cooperatively breeding species forego all or partof their reproduction when remaining at home and assisting breedersto raise offspring. Different models of reproductive skew generatealternative predictions about the share of reproduction unrelatedsubordinates will get depending on the degree of ecologicalconstraints. Concession models predict a larger share when independentbreeding options are good, whereas restraint and tug-of-warmodels predict no effects on reproductive skew. We tested thesepredictions by determining the share of reproduction by unrelatedmale and female helpers in the Lake Tanganyika cichlid Neolamprologuspulcher depending on experimentally manipulated possibilitiesfor helper dispersal and independent breeding and dependingon helper size and sex. We created 32 breeding groups in thelaboratory, consisting of two breeders and two helpers each,where only the helpers had access to a nearby dispersal compartmentwith (treatment) or without (control) breeding substrate, usinga repeated measures design. We determined the paternity andmaternity of 1185 offspring from 47 broods using five to nineDNA microsatellite loci and found that: (1) helpers participatedin reproduction equally across the treatments, (2) large malehelpers were significantly more likely to reproduce than smallhelpers, and (3) male helpers engaged in significantly morereproduction than female helpers. Interestingly, in four broods,extragroup helper males had fertilized part of the brood. Nohelper evictions from the group after helper reproduction wereobserved. Our results suggest that tug-of-war models based oncompetition over reproduction within groups describe best thereproductive skew observed in our study system. Female breedersproduced larger clutches in the treatment compared to the controlsituation when the large helpers were males. This suggests thatmale breeder-male helper reproductive conflicts may be alleviatedby females producing larger clutches with helpers around.     

CO-OPERATIVE BREEDING IN THE PIED STARLING

Craig, A. J. F. K. 1987. Co-operative breeding in the Pied Starling. Ostrich 58:176-180.

Pairs of Pied Starlings Spreo bicolor build the nest, but only the female incubates. After the chicks hatch, subadult and juvenile birds help feed the young. Helpers also feed young after they leave the nest. In most cases parents contribute more than the helpers which may attend several different nests. Associations between members of the same breeding group may persist for up to three successive seasons.     

Genetic analysis reveals diverse kin‐directed routes to helping in the rifleman Acanthisitta chloris

The social organization of cooperatively breeding species is extremely variable, with diverse social group composition and patterns of relatedness. Species that exhibit alternative routes to helping within the same population are potentially useful systems to investigate the causes and fitness consequences of diverse evolutionary pathways to cooperative behaviour. In this study, we use microsatellite markers and field observations to describe helping behaviour and patterns of relatedness in the unusual cooperative breeding system of the rifleman Acanthisitta chloris. First, we show that rifleman helpers consist of a remarkably diverse demographic, including males and females, who may be adult or juvenile, failed breeders or nonbreeders, or even successful breeders that simultaneously feed their own brood. Adult helpers mostly helped at first‐brood nests, while first‐brood juveniles assisted their parents at second broods. Second, we show that rifleman pairs are strictly sexually monogamous, and helpers did not gain any current reproductive success through helping. Third, genotyping showed that contrary to previous assumptions, helpers were closely related to the recipients of their care and preferentially directed care towards relatives over contemporaneous nests of nonrelatives. Finally, we show that variation in helper provisioning effort was attributed to age: juvenile helpers provisioned less than adults and were less responsive to the demands of a growing brood. Overall, our results show that the diverse routes to helping in this unusual species are driven by the common theme of kinship between helper and recipients, resulting in a previously underestimated potential for helpers to gain indirect fitness benefits.