Sensitivity of breeding parameters to food supply in Black-legged Kittiwakes Rissa tridactyla

We fed Herring Clupea pallasi to pairs of Black-legged Kittiwakes Rissa tridactyla throughout the breeding season in two years at a colony in the northern Gulf of Alaska. We measured responses to supplemental feeding in a wide array of breeding parameters to gauge their relative sensitivity to food supply, and thus their potential as indicators of natural foraging conditions. Conventional measures of success (hatching, fledging and overall productivity) were more effective as indicators of food supply than behavioural attributes such as courtship feeding, chick provisioning rates and sibling aggression. However, behaviour such as nest relief during incubation and adult attendance with older chicks were also highly responsive to supplemental food and may be useful for monitoring environmental conditions in studies of shorter duration. On average, the chick-rearing stage contained more sensitive indicators of food availability than prelaying or incubation stages. Overall, rates of hatching and fledging success, and the mean duration of incubation shifts were the most food-sensitive parameters studied.     

Breeding season weather determines long‐tailed tit reproductive success through impacts on recruitment

Productivity is a key demographic trait that can be influenced by climate change, but there are substantial gaps in our understanding of the impact of weather on productivity and recruitment in birds. Weather is known to influence reproductive success in numerous species, although such effects have not been reported in all studies, perhaps because they are masked by high nest predation rates or buffered by density dependence. Here, we use a 19‐yr study of a population of individually marked long‐tailed tits Aegithalos caudatus to quantify the impacts of weather on productivity in the nest (from eggs to fledging) and subsequent recruitment, while taking nest predation rates and density dependence into account. We find that weather has negligible effects on clutch size, hatching success, brood size, probability of fledging and number of fledglings. Annual variation in nest predation rates is a strong predictor of productivity, but we find no evidence that the magnitude of nest predation is determined by weather. Recruitment was strongly associated with breeding season weather, even when taking density dependence effects into account. This contrasts with the conventional view that first year survival of temperate passerines is primarily determined by winter weather. Recruitment was reduced when March temperatures were high, perhaps caused by earlier peaks in caterpillar abundance and thus reduced food availability at the time of fledging. Recruitment increased following high May temperatures, perhaps due to an improved thermo‐regulatory environment for young fledglings. These opposing effects of warm March and May temperatures highlight the importance of considering asymmetrical rates of warming in different months when predicting climate change impacts.     

Density-dependent effects on productivity in the Griffon Vulture Gyps fulvus: the role of interference and habitat heterogeneity

Griffon Vultures Gyps fulvus in northern Spain were studied between 1969 and 1994. The number of breeding pairs increased from 221 in 1969–1975 to 1395 in 1994. The annual population growth rate decreased in the last 5 years, and this may reflect population regulation through density-dependent phenomena. Breeding success was monitored in 1994 and examined in relation to colony size, density of breeding pairs within a radius of 25 km (regional density), climate, human disturbance and food availability. We also recorded whether the year of first occupation of each nest site was before 1989 or after 1989 and whether or not the nest had a rocky shelter. The probability of successfully raising young declined as the regional density increased, which suggests that resource limitation would take place at foraging sites because the Griffon Vulture scavenges socially and no permanent feeding hierarchies are established. The other significant variable was the year of occupation of the nest; nests occupied after 1989 had a lower probability of raising a chick. The increase in the regional density of Griffon Vultures produced a decrease in the productivity at both optimal and suboptimal nest sites. This suggests that density-dependent regulation of breeding success operates through interference and that all the individuals in a colony are similarly affected. In birds of prey, prevalence of interference or habitat heterogeneity may be dependent on the social strategy of each species in space exploitation.     

Lazy group members are substitute helpers in carrion crows

In many cooperatively breeding societies, helping effort varies greatly among group members, raising the question of why dominant individuals tolerate lazy subordinates. In groups of carrion crows Corvus corone corone, helpers at the nest increase breeders'' reproductive success, but chick provisioning is unevenly distributed among non-breeders, with a gradient that ranges from individuals that work as much as the breeders to others that completely refrain from visiting the nest. Here we show that lazy non-breeders represent an insurance workforce that fully compensates for a reduction in the provisioning effort of another group member, avoiding a decrease in reproductive success. When we temporarily impaired a carer, decreasing its nest attendance, the laziest non-breeders increased their provisioning rate and individuals that initially refrained from visiting the nest started helping. Breeders, in contrast, did not increase chick provisioning. This shows that lazy non-breeders can buffer a sudden unfavourable circumstance and suggests that group stability relies on the potential contribution of group members in addition to their current effort.     

Anthropogenically-Mediated Density Dependence in a Declining Farmland Bird

Land management intrinsically influences the distribution of animals and can consequently alter the potential for density-dependent processes to act within populations. For declining species, high densities of breeding territories are typically considered to represent productive populations. However, as density-dependent effects of food limitation or predator pressure may occur (especially when species are dependent upon separate nesting and foraging habitats), high territory density may limit per-capita productivity. Here, we use a declining but widespread European farmland bird, the yellowhammer Emberiza citrinella L., as a model system to test whether higher territory densities result in lower fledging success, parental provisioning rates or nestling growth rates compared to lower densities. Organic landscapes held higher territory densities, but nests on organic farms fledged fewer nestlings, translating to a 5 times higher rate of population shrinkage on organic farms compared to conventional. In addition, when parental provisioning behaviour was not restricted by predation risk (i.e., at times of low corvid activity), nestling provisioning rates were higher at lower territory densities, resulting in a much greater increase in nestling mass in low density areas, suggesting that food limitation occurred at high densities. These findings in turn suggest an ecological trap, whereby preferred nesting habitat does not provide sufficient food for rearing nestlings at high population density, creating a population sink. Habitat management for farmland birds should focus not simply on creating a high nesting density, but also on ensuring heterogeneous habitats to provide food resources in close proximity to nesting birds, even if this occurs through potentially restricting overall nest density but increasing population-level breeding success.     

Sea surface temperatures and behavioural buffering capacity in thin-billed prions Pachyptila belcheri: breeding success, provisioning and chick begging

Seabirds are important predators in marine ecosystems and are commonly used to monitor the productivity of their marine environments. However, different measures of seabird breeding success differ in their sensitivity to environmental conditions. Here, we present an analysis of provisioning rates and chick growth as well as hatching and fledging success, in thin-billed prions Pachyptila belcheri at New Island, Falkland Islands between 2003 and 2005 and relate these patterns to ocean climate. During the study period, SST were rising within and between breeding seasons and were negatively correlated with provisioning frequencies of thin-billed prions. Chick mass was reduced and begging intensities increased at low feeding frequencies, but overall breeding success and fledging success were not affected, because most chicks in survived to fledging despite poor provisioning rates. Chick numbers and survival therefore may not be sensitive indicators of environmental conditions in all seabird species and ranges of food abundance. Monitoring behavioural buffering mechanisms, such as feeding rates, may be more effective in some ranges of food abundance and time scales and provide an earlier warning of ecological change. As a novel technique, the use of begging intensities as indicator of chick body condition is proposed in species where repeated handling causes disturbance. The present data suggest that begging rates can serve as a non-invasive method to monitor chick condition.     

The demography of a newly established Osprey Pandion haliaetus population in France

Using long‐term mark–resighting data acquired over 27 years in continental France, we estimated demographic parameters and modelled the dynamics of a newly established population of Ospreys Pandion haliaetus using a life‐history model. We then performed prospective and retrospective analyses to estimate the sensitivity of the population growth rate to demographic parameters, and to quantify their contribution to the observed variation in abundance. The observed population growth rate was estimated at 1.150 (from one to 38 pairs in the period 1985–2011), and the stochastic population growth rate was estimated at 1.156. The number of fledglings per nest made the largest contribution to the variance of the observed population growth rate. Breeding productivity was stable across years. In contrast, the prospective analysis indicated that the sensitivity of the population growth rate was greatest for immigration and adult survival. Our results suggest that the increase of a new and recently established breeding population of Ospreys was mainly driven by local dynamics (high productivity and high proportion of breeding individuals), with no sign of density‐dependence except for juvenile survival. This probably reflects highly favourable conditions for breeding. Our results show that productivity can be a major driver in recovering raptor populations, and conservation work should aim to protect occupied nest‐sites and their surrounding habitat and to maintain highly favourable foraging areas in the vicinity of breeding sites.     

Investigating patterns and processes of demographic variation: environmental correlates of pre-breeding survival in red-billed choughs Pyrrhocorax pyrrhocorax

1. Quantifying the pattern of temporal and spatial variation in demography, and identifying the factors that cause this variation, are essential steps towards understanding the structure and dynamics of any population. 2. One critical but understudied demographic rate is pre-breeding survival. We used long-term colour-ringing data to quantify temporal (among-year) and spatial (among-nest site) variation in pre-breeding survival in red-billed choughs (Pyrrhocorax pyrrhocorax) inhabiting Islay, Scotland, and identified environmental correlates of this variation. 3. Random-effects capture-mark-recapture models demonstrated substantial temporal and spatial process variance in first-year survival; survival from fledging to age 1 year varied markedly among choughs fledged in different years and fledged from different nest sites. Spatial variance exceeded temporal variance across choughs fledged from well-studied nest sites. 4. The best-supported models of temporal variation suggested that first-year survival was higher in years following high tipulid larvae abundance and when weather conditions favoured increased invertebrate productivity and/or availability to foraging choughs. These variables explained up to 80% of estimated temporal process variance. 5. The best-supported models of spatial variation suggested that first-year survival was higher in choughs fledged from nest sites that were further from exposed coasts and closer to flocking areas, and surrounded by better habitat and higher chough density. These variables explained up to 40% of estimated spatial process variance. 6. Importantly, spatio-temporal models indicated interactive effects of weather, tipulid abundance, local habitat and local chough density on first-year survival, suggesting that detrimental effects of poor weather and low tipulid abundance may be reduced in choughs fledged from nest sites surrounded by better foraging habitat and lower chough density. 7. These analyses demonstrate substantial temporal and small-scale spatial variation in pre-breeding survival, a key demographic rate, and indicate that this variation may reflect interactive effects of weather, prey abundance, habitat and geography. These patterns illustrate the value of holistic models of demographic variation, and indicate environmental factors that may limit the growth rate of Islay's protected chough population.     

Nesting outcomes under anthropogenic change – effects of changing climate and nestbox provision on the reproduction of Great Tits Parus major

Global anthropogenic changes are significantly impacting the ecology and evolution of many species. Among temperate taxa, changes to reproductive phenology as a result of warming springs are apparent. However, how such responses to abiotic change interact with biotic impacts resulting from human management interventions are less clear. Here we examine the response of a range of breeding metrics (laying date, clutch size, hatching and fledging success) to interactions between climatic variables and changes in conspecific density (and hence intraspecific competition) resulting from changes in nestbox provision. Using a 37‐year dataset on the Great Tit Parus major we found little evidence for interacting effects of these two drivers. Instead we found that either climatic or competitive effects were the key influence on different metrics. Annual mean laying date substantially advanced with a warming climate, whereas clutch size, hatching success and fledging success were significantly inversely associated with conspecific density. Annual variance in clutch size and hatching success increased weakly with measures of conspecific density, but there was no association between either climatic or density measures and the annual variance in laying date or fledging success. Increasing conspecific densities therefore resulted in years with lower, but more variable, reproductive rates. These results highlight the importance of adaptive provisioning of nestboxes to enhance reproductive output of hole‐nesting birds regardless of climate‐induced phenological change. Such management is likely to be appropriate for assisting with sustaining populations responding to a changing climate.     

Multiple sources of evidence for density dependence in the endangered Hawaiian stilt (Himantopus mexicanus knudseni)

Hawaiian stilts (Himantopus mexicanus knudseni) are an endangered subspecies of the Black-necked stilt endemic to the Hawaiian Islands. Despite long-term study, the main drivers of Hawaiian stilt population dynamics are poorly understood. We tested for density dependence using two sources of evidence: a 30-year time series of annual estimated range-wide abundance, and two 15+ year time series of reproductive success. Using separate methods with independent data, sources allowed us to make up for the potentially positive bias of one approach with the more conservative nature of the second. We compared nonlinear density-dependent and density-independent population model fits to our time-series data, using both frequentist and Bayesian state-space approaches. Across both approaches, density-dependent models best fit observed population dynamics, with lower AICc and cross-validation statistics compared to density-independent models. Among density-dependent models, a conditional model in which density-independent dynamics occur below a population size threshold (~850–1,000 birds), and then density-dependent dynamics occur above that threshold, performed best across Bayesian and frequentist model comparisons, with the Ricker model ranked next or equivalently. Our analysis of reproduction data revealed a strong negative effect of local adult density on nest success (proportion of nests hatching at least one chick) at Kealia National Wildlife Refuge on Maui, where few alternative breeding habitats are available, but no such effect at another site where many nearby alternative wetlands are available. These congruent results across independent datasets and analytical approaches support the hypothesis that Hawaiian stilts exhibit density dependence across their range.     

Factors affecting breeding success of the Flea Bay white-flippered penguin (

The little blue penguin (Eudyptula minor) is in decline throughout much of its range in New?Zealand and Australia, largely due to introduced predators, human disturbance and roadkill mortalities. The white-flippered penguin is a unique morphological variant of the blue penguin, which is traditionally given subspecific status (Eudyptula minor albosignata), and is found only on Banks Peninsula and Motunau Island in Canterbury, New?Zealand. We monitored a varying number of nest boxes from 1996 to 2009. Overall breeding success was 64% over 13 years of monitoring, with a hatching success rate of 75% and a fledging success rate of 85%. We used a set of generalised linear mixed models and model selection to examine the relative influence of various explanatory variables on hatching, fledging and overall breeding success. Breeding success in nest boxes significantly increased with shorter average pair bond length, longer guard period and later relative lay date. Guard period length was the best predictor of breeding success, followed by relative lay date and average pair bond length. Hatching success also increased with later relative lay date but fledging success was not influenced by any of the explanatory variables measured.     

The impact of climate fluctuation on food availability and reproductive performance of the planktivorous red-billed gull Larus novaehollandiae scopulinus

1. Using 41 years of data, we examined annual variations in the reproductive performance of the red-billed gull at the Kaikoura Peninsula, New Zealand and related these to changes in climate, oceanography and the availability of the planktonic euphausiid Nyctiphanes australis, the bird's principal food. 2. In 1994 the population began to decline, and between 1983 and 2003 it was reduced by 51%. Adult non-breeders comprised an average of 32% of the population between 1983 and 1994, but following the decline they averaged only 18%. The age at recruitment changed markedly following the population decline: 27% of 2-year-old males bred for the first time prior to the decline, whereas the corresponding figure after the decline was 38%. The proportion of females commencing to breed as a 3-year-old was not significantly different before or after the decline. 3. An increase in the availability of euphausiids increased the likelihood of breeding and the recruitment of young individuals, caused earlier laying and resulted in an increase in the condition of adults, egg volume of gulls laying two egg clutches, clutch size and fledging success. 4. The relationship between food availability and the number of pairs that bred, laying date, clutch size and fledging success was significantly different prior to and after the population decline. The underlying cause appears to be a compensatory density-dependent mechanism that reduced interspecific competition for food. 5. The relative abundance of N. australis was correlated positively with the Southern Oscillation Index (SOI) and the frequency of occurrence of NE winds. The proportion of non-breeders and mean laying date were correlated negatively with the SOI, and mean egg volume of two egg clutches correlated positively with the SOI. 6. These results emphasize that availability of adult euphausiids is critical for red-billed gulls. We hypothesize that high primary productivity of inshore water near Kaikoura in winter, linked to a stable water column of coastal water and upwelling of additional dissolved inorganic nutrients, increases the availability of adult euphausiids to the red-billed gull as long as the coastal water is not replaced by offshore subtropical water intrusions of warmer, low-nutrient water.     

Breeding biology and breeding success of the Lesser Grey Shrike Lanius minor in a stable and dense population

The Lesser Grey Shrike Lanius minor is highly endangered throughout Europe, having declined markedly in abundance and range. Long-term changes in climate and agricultural practices have been identified as the main reasons for its decline. To determine which factors influence short-term changes in breeding success, we examined several aspects of its breeding biology. Our investigation revealed that our study area bears a large and stable population of this species. In 1996 and 1997, we recorded 84 and 77 breeding pairs in an area of 20 km², with an average of 4.20 and 3.85 pairs/km² respectively. Data on breeding density, clutch size and fledging success from 1989 to 1997 (excluding 1992) indicate a stable breeding population with a constant high breeding success. Reproductive success declined through the season, mainly through seasonal variation in clutch size rather than chick mortality. However, breeding success was generally high (69% and 79% of the nests produced chicks], with low hatching failure and few nest losses. The main cause of breeding failure was nest predation (at least 50% of nest losses), mainly by magpies (at least 66% of depredated nests). Although in this population the Lesser Grey Shrike tends to aggregate in clusters, breeding density had no obvious effect on breeding success and nest predation.     

Survival of Herring Gull Larus argentatus chicks: an experimental analysis of the need for early breeding

In 1985 and 1990, we manipulated the hatching date of Herring Gulls Larus argentatus by exchanging complete clutches between pairs which had started egg laying on different dates in the season. The aim was to investigate whether the observed seasonal decline in Hedging success can be explained by laying date. In both years, fledging success of advanced pairs followed the natural seasonal trend, supporting the date hypothesis. However, in both years, Hedging success of delayed pairs remained as high as that of control pairs with the same original hatching date as the foster parents, supporting the parental quality hypothesis. These data suggest that the delayed pairs may have compensated for less favourable environmental conditions. Although conspecific predation was the main direct cause of chick mortality, food shortage probably indirectly determined the mortality rate. A model of fledging success in relation to the timing of egg laying predicts that when food is abundant the optimal hatching date coincides with the mean hatching date of the colony (synchronization advantage). When food is less abundant, early breeders have the highest fledging success.     

Long‐term breeding demography and density dependence in an increasing population of Golden Eagles Aquila chrysaetos

Few studies have quantified the dynamics of recovering populations of large raptors using long‐term, spatially explicit studies. Using data collected over 37 years in the western Italian Alps, we assessed the trends in distribution, abundance, fecundity and breeding population structure of Golden Eagles Aquila chrysaetos. Using the spatial distribution of territory centroids in 2007, we found that the spatial distribution of eagle territories was over‐dispersed up to 3 km. Although population size and total productivity increased from 1972 to 2008, the proportion of pairs that laid eggs showed a strong decline, falling to no more than 50% after 2003. On average, 15% of successful nests produced two fledglings, and productivity also declined over time. No significant relationship between population growth rate and total population size was detected, but the percentage of pairs that bred and breeding success showed evidence of density dependence, as they declined significantly with increasing density. Our results suggest that density dependence, operating across heterogeneous habitats, is currently regulating this population, while the carrying capacity may still be increasing. This may explain the apparent paradox of reduced breeding effort despite increasing total productivity.     

Density-dependent effects on hatching success of the olive ridley turtle, Lepidochelys olivacea

Historically, the olive ridley arribada at Playa Nancite, Costa Rica, was one of the largest olive ridley arribadas in the eastern Pacific with 70,000 nesting females in a year. Recently the Nancite arribada drastically declined. We hypothesized that the population decline at Playa Nancite could have been due to low hatching success as a result of the high density of nests on the beach, such that recruitment to the population was insufficient to balance losses. To test this hypothesis, we examined density-dependent effects on hatching success and their underlying mechanisms by experimentally manipulating nest densities in experimental plots on the nesting beach. We set up four nest-density treatments in five experimental blocks. We measured effects of density on hatching success, CO(2) and O(2) concentrations and temperature both within nests and in sand adjacent to nests frequently during incubation. Experimental nest densities affected hatching success with the highest density having the lowest hatching success. Higher nest density led to lower O(2) levels and higher CO(2) levels in the nest with greater changes in the latter part of the incubation. Highest temperatures occurred in high-density areas. Temperatures were lower in sand surrounding the nest than in the nest. Effects of density on temperature, CO(2) and O(2) were confirmed at a naturally high-density nesting beach, Playa La Flor, Nicaragua. Long-term failure in production of hatchlings due to historic high densities may have contributed to the decline of arribadas on Playa Nancite. Thus, density-dependent population control would have operated at the embryonic life stage in this population of olive ridley turtles.     

Chick loss in the Falkland Skua Catharacta skua antarctica

Data on reproductive success of 110 Falkland Skua Catharacta skua antarctica pairs were gathered during the austral summers of 1988–1989 and 1990–1991 on New Island, Falkland Islands. Adults laid two eggs 2–3 days apart and began incubation with the first egg. For the years combined, 1.39 chicks per nest hatched and 0.84 chicks per nest fledged (fledging was defined as surviving to 16 days of age). Brood reduction was common; 43% of the two-chick broods were reduced to one, and mortality was concentrated on the younger chick. Although asynchronous hatching and differential death are consistent with Lack's brood reduction hypothesis, application of O'Connor's quantitative criterion revealed that sibling competition may not be responsible for the observed chick mortality. Furthermore, because no aggressive interactions between chicks were observed or detected indirectly, siblicide may be absent in this population. Instead, predation modified by a variety of factors may have led to the greater mortality of the second-hatched chick.     

Individual variation in parental workload and breeding productivity in female European starlings: is the effort worth it?

We analyzed individual variation in work load (nest visit rate) during chick‐rearing, and the consequences of this variation in terms of breeding productivity, in a highly synchronous breeder, the European starling (Sturnus vulgaris) focusing on female birds. There was marked (10‐ to 16‐fold) variation in total, female and male nest visit rates, among individuals, but individual variation in female nest visit rate was independent of environment (rainfall, temperature) and metrics of individual quality (laying date, clutch size, amount of male provisioning help), and was only weakly associated with chick demand (i.e., day 6 brood size). Female nest visit rate was independent of date and experimentally delayed birds provisioned at the same rate as peak‐nesting birds; supporting a lack of effect of date per se. Brood size at fledging was positively but weakly related to total nest visit rate (male + female), with >fivefold variation in nest visit rate for any given brood size, and in females brood size at fledging and chick mass at fledging were independent of female nest visit rate, that is, individual variation in workload was not associated with higher productivity. Nevertheless, nest visit rate in females was repeatable among consecutive days (6–8 posthatching), and between peak (first) and second broods, but not among years. Our data suggest that individual females behave as if committed to a certain level of parental care at the outset of their annual breeding attempt, but this varies among years, that is, behavior is not fixed throughout an individual's life but represents an annually variable decision. We suggest females are making predictable decisions about their workload during provisioning that maximizes their overall fitness based on an integration of information on their current environment (although these cues currently remain unidentified).     

Quantifying density dependence in a bird population using human disturbance

Although density dependence has long been recognised as vital to population regulation, there have been relatively few studies demonstrating it spatially in wildlife populations, often due to the confounding effects of variation in habitat quality. We report on a study of woodlarks Lullula arborea, a species of European conservation concern, breeding on lowland heath in Dorset, England. We take the novel approach of utilising the birds’ response to human disturbance, which resulted in much of the variation in density but had no direct impact on demographic rates. Within years, in sites with greater density there were smaller mean chick masses, lower post-fledging survival, and higher rates of nestling mortality attributed to starvation. The effects on clutch size and fledging success were confounded by the area of grassland within a site. There was no effect on brood size. Density dependence also operated within sites between years: as density increased there were reductions in mean chick mass and post-fledging survival, while nestling mortality attributed to starvation increased. Density-dependent effects on clutch size were only weakly regulatory, whereas density-dependent starvation and post-fledging mortality rates contributed strongly to differences in overall breeding output. Heavier chicks (when 7 days old) were significantly more likely to fledge and less likely to starve. Broods with heavier chicks were more likely to supply recruits to the breeding population. Nestling mass was not a factor in survival in the immediate post-fledging period, suggesting that density-dependent processes act independently on this stage. We conclude that the number of birds per hectare of suitable habitat is a valid means of expressing density, and that habitat acts as a surrogate for food abundance through which density dependence operates on the woodlark population.     

Contemporary breeding biology of critically endangered Regent Honeyeaters: implications for conservation

Identifying factors influencing the demographics of threatened species is essential for conservation, but a lack of comprehensive demographic data often impedes the effective conservation of rare and mobile species. We monitored breeding of critically endangered and semi‐nomadic Regent Honeyeaters Anthochaera phrygia (global population c. 100 pairs) over 3 years throughout their range. Overall nest success probability (0.317) was highly spatially variable and considerably lower than previous estimates for this (and many other honeyeater) species, as was productivity of successful nests (mean 1.58 juveniles fledged). Nest surveillance revealed high predation rates by a range of birds and arboreal mammals as the primary cause of nest failure. An estimated 12% of pairs either failed to establish a territory or their nests did not reach the egg stage. We also found a male bias to the adult sex ratio, with an estimated 1.18 males per female. Juvenile survival for the first 2 weeks after fledging was high (86%). Management interventions that aim to increase nest success in areas of low nest survival must be investigated to address an apparent decline in reproductive output and avoid extinction of the Regent Honeyeater. We show that temporal and spatial variation in the breeding success of rare and highly mobile species can be quantified with robust population monitoring using sampling regimens that account for their life histories. Understanding the causes of spatio‐temporal variation in breeding success can enhance conservation outcomes for such species through spatially and temporally targeted recovery actions.