Nest Failure Research Articles

Nesting behaviour and ecology of the White-browed Fantail Flycatcher (Rhipidura aureola) in Sri Lanka

The White-browed Fantail Flycatcher (Rhipidura aureola) is a widely distributed species in tropical regions of the Indian subcontinent and in Southeast Asia. We determined the breeding biology and nest site characteristics of R. aureola in Sri Lanka during 2012 to 2017. All the nests observed were small cup-shaped and without a ‘tail’ extending below the nest base. Both male and female R. aureola built their nests within 9–13 days with an average mean external diameter, mean internal diameter, and mean depth of, respectively, 6.4 ± 0.32, 5.6 ± 0.22, and 2.9 ± 0.21 cm. The R. aureola we found used various habitats such as home gardens, forest boundaries, sanctuaries, man-made tanks/water bodies, stream banks, tea plantations and road edges to build their nests. We did not find any change in clutch size (2–3 eggs) with different elevation gradients. The eggs were oval-shaped with the ground colour of pale warm yellow-brown to pink and lots of spots or blotches in dark gray-brown. More than 60% of nests were built in a high to medium range of visibility to predators, without a specific location or tree preference, which resulted in nest failure due to predation by domestic cats or birds of prey. Also, we found nest failure due to washing away by abundant rains. Detailed studies on ecological and environmental parameters with respect to nesting or breeding success will help to better understand the species.

Are artificial agricultural ponds a suitable alternative nesting habitat for the Little Ringed Plover?

Climatic scenarios for the Mediterranean predict an increase in drought and erratic precipitation, which may affect waterbirds breeding in freshwater habitats. Artificial wetlands may provide an alternative for these species when conditions in natural habitats deteriorate. We studied Little Ringed Plovers Charadrius dubius nesting in natural streams and agricultural ponds in southern Portugal. Based on 24 nests and 31 colour-ringed adults, we describe nest-site characteristics, breeding parameters and site fidelity. In streams, nests (n = 17) were in sites with more abundant and coarser gravel, while in ponds there was more vegetation around the nest (n = 7). In both habitats, nests were close and at similar distances to water, but this was unrelated to nest outcome (success of 30.8% across habitats). Nest failure in natural streams was mostly attributable to flooding after heavy rains, while in agricultural ponds cattle trampling was the main cause of failure. Based on their renesting capacity and relatively high breeding site fidelity (25%–36% return rate to same area), we suggest that Little Ringed Plovers may trade-off the overall better conditions of natural streams (i.e. higher availability of nesting substrate, food resources and lower disturbance from cattle) against the stochastic risk of floods. Nevertheless, under current predictions of climate change, agricultural ponds can provide more stable and reliable nesting conditions for this and other species, as unpredictable changes in Mediterranean streams’ flooding regimen may become more frequent. Despite the limitations of our dataset, we provide novel information on the breeding biology of this understudied species and highlight its potential for future research.

Survival and productivity benefits of sociality vary seasonally in the tropical, facultatively eusocial bee Megalopta genalis

Tropical habitats are characterized by strong wet and dry seasons, but the effects of seasonality on the costs and benefit of sociality are largely unknown for tropical insects. This is an important gap in our understanding of sociobiology because many social bees and wasps are in the tropics. We found evidence of seasonal effects on the costs and benefits of social and solitary behavior in the tropical sweat bee Megalopta genalis. Productivity, whether measured as brood cell production per nest, or brood cell production per female, was greater in the dry season than the wet, likely reflecting floral resource availability. Per nest productivity was greater in social nests than solitary, but this difference was only significant in the dry season. Conversely, per capita productivity was greater in solitary than social nests, but again only in the dry season. Nest failure rates were also higher in the wet season, although roofs protecting nests from rain did not increase survival, suggesting that increased foraging effort in the face of declining resources rather than wetness per se led to nest failure. Newly initiated nests had higher failure rates than established nests, but these were not affected by season. Social nests collected late in the wet season after reproduction has largely ceased show that M. genalis can live in social groups without reproduction; these bees are likely waiting together until provisioning resumes in the subsequent dry season. Our results suggest that the productivity benefits of social nesting are greatest in the dry season, but that insurance-based benefits to social nesting may be greater in the wet season. This reveals that the costs and benefits underpinning sociality are dynamic across seasons, even in tropical systems.

Nesting ecology and parental care of the Sabota Lark (Calendulauda sabota) in a savanna landscape in South Africa

We report on the breeding biology of the Sabota Lark (Calendulauda sabota), a widespread and common but poorly known species. We present the results of data collected at 57 nests over 2 breeding seasons (2011–2013). Breeding coincided with the peak of the wet season in the study area and the breeding season appeared to be shorter in the study area compared to the rest of the species' range. Only females were observed constructing nests and laying and incubating started before the nest was completed, a strategy to reduce the overall nesting time. Nest quality varied considerably, including in the presence or absence of a dome and an apron. The mean clutch size was 2.5 ± 0.5 with incubation commencing upon clutch completion, performed by the female only and lasting 12.3 ± 0.5 d. Mean nest attendance during incubation was 74% and there was a steady increase in the duration of incubation on-bouts with progression of the incubation period. The mean nestling period lasted 11.7 d with both parents delivering food and both sexes performing brooding duties, a seemingly unique feature in the mirafrid clade of larks. There was evidence of subtle sex-specific roles during the nestling period with females primarily being responsible for brooding and males mainly provisioning. Breeding success using Mayfield's estimator was 33% with predation being the main cause of nest failure. Given the relatively poor breeding success, replacement broods were common but repeat-brooding attempts in a single season were rare with only 2 records during the course of this study. Although many of the reproductive features of Sabota Lark were similar to those of other larks, there were some differences and some apparently unique features that contribute to our knowledge of the Alaudidae.

Behavioural and reproductive flexibility of an invasive bird in an arid zone: A case of the Indian House Crow (Corvus splendens)

Of all the invasive species, 20–30% are considered as pests that cause ecological and economic damage. They are considered a threat to the natural environment second only to habitat loss. In the framework of a broader study of the breeding ecology of the invasive Indian House Crow in the arid city of Eilat, we observed the behavioural plasticity and reproductive versatility in the face of a stochastic event in the form of a strong thunder storm. Crows that nested in palm crowns recorded total nest failures owing to inundation of the nests. Pairs that built their nest under the palm crowns or in Tamarix and Eucalyptus trees survived the storm without any nest losses. Eight days later, the crows that lost their broods initiated new nests on the same palms, but all were located under the crowns. The replacement clutches were smaller in comparison to the first breeding attempts of the same pairs but the number of fledglings did not differ from the first and only breeding attempts of the other breeding pairs which did not suffer from the storm. A year later, in the next breeding season, a total of 31 active nests were found in palm trees and all were placed under the crown. Our study demonstrates the resilience and behavioural flexibility connected with a fast learning process of the invasive House Crow, and its ability to overcome environmental handicaps.

Nest initiation and flooding in response to season and semi-lunar spring tides in a ground-nesting shorebird

BackgroundMarine and intertidal organisms face the rhythmic environmental changes induced by tides. The large amplitude of spring tides that occur around full and new moon may threaten nests of ground-nesting birds. These birds face a trade-off between ensuring nest safety from tidal flooding and nesting near the waterline to provide their newly hatched offspring with suitable foraging opportunities. The semi-lunar periodicity of spring tides may enable birds to schedule nest initiation adaptively, for example, by initiating nests around tidal peaks when the water line reaches the farthest into the intertidal habitat. We examined the impact of semi-lunar tidal changes on the phenology of nest flooding and nest initiation in Snowy Plovers (Charadrius nivosus) breeding at Bahía de Ceuta, a coastal wetland in Northwest Mexico.ResultsUsing nest initiations and fates of 752 nests monitored over ten years we found that the laying season coincides with the lowest spring tides of the year and only 6% of all nests were flooded by tides. Tidal nest flooding varied substantially over time. First, flooding was the primary cause of nest failures in two of the ten seasons indicating high between-season stochasticity. Second, nests were flooded almost exclusively during the second half of the laying season. Third, nest flooding was associated with the semi-lunar spring tide cycle as nests initiated around spring tide had a lower risk of being flooded than nests initiated at other times. Following the spring tide rhythm, plovers appeared to adapt to this risk of flooding with nest initiation rates highest around spring tides and lowest around neap tides.ConclusionsSnowy Plovers appear generally well adapted to the risk of nest flooding by spring tides. Our results are in line with other studies showing that intertidal organisms have evolved adaptive responses to predictable rhythmic tidal changes but these adaptations do not prevent occasional catastrophic losses caused by stochastic events.

Nesting season, nest age, and disturbance, but not habitat characteristics, affect nest survival of Chinese grouse.

Nest survival is a vital component of breeding success, and affects population dynamics, as the loss of nests is the main cause of reproductive failure in birds. To identify key factors for the conservation of Chinese grouse Tetrastes sewerzowi, we tested the effects of nest concealment, nest age, nesting season, and habitat edge on nest daily survival rate (DSR) of Chinese grouse using 54 nests found at Lianhuashan Nature Reserve, Gansu, China, 2009–2012. Moreover, we controlled for the effect of research activity by testing the effect of nest checks on DSR. Overall, mammal predation caused 93% of nest failures. DSR was 0.986 ± 0.0038 in the constant model and the probability of a nest with a full clutch of 6 eggs surviving the entire 40-day nesting period was 0.526 ± 0.090. DSR decreased with nest age and nesting season (from 19 May to 3 July). Mammals instead of avian predators being responsible for most nest failures suggest that nest sites might be selected to avoid visual avian predators, but not olfactory mammalian predators, and the decreasing trend of DSR with nest age and nesting season could attribute to an additive exposure effect. Moreover, nest checks conducted by investigators significantly lowered nest DSR, especially during the late period of nesting season and for older nests. Mammalian predators might locate the nest site by following the investigator’s odor. Based on our results, we suggest that the late incubation stage is a particularly vulnerable period for nest survival of Chinese grouse and those researchers should adjust their activities around nests to balance the need of acquiring accurate data and decreasing nest predation risk.

The Breeding Biology of the Endemic Azores Woodpigeon Columba palumbus azorica

The Azores Woodpigeon Columba palumbus azorica is considered an endemic subspecies and is currently listed in the Annex I of the EU Birds Directive. However, despite its status, the bird has rarely been studied and is classified as ‘Data Deficient’ in the Portuguese Red Data Book. Herewith, we present the first results on the breeding biology of this subspecies, based on data collected from November 2012 to October 2014 on Terceira Island. Data were obtained by monitoring nests, and additional information on breeding phenology was provided during regular counts from 100 points distributed over the island. Fifty-four nests were found mainly in exotic trees, suggesting that the species does not depend on the highly degraded native laurel forest for nesting. Egg-laying occurred from late-February to late-September, reaching its peak in May; the main laying period lasted 140 days from 1 April to 19 August. Mean clutch size (±SE) was 1.77 ± 0.06 eggs (range 1–2 eggs) and did not vary with time. Overall breeding success, calculated using the Mayfield method, was amongst the lowest ever detected for this species across its breeding range: 0.091 ± 0.048 (SE). Extreme weather events and predation by introduced mammals are likely to explain high nest failure. The population is likely to have undergone a period of growth since 1992, following a period in the 1960's when the bird was very scarce in the Archipelago due to hunting pressure. In recent years, farmers have increasingly complained to the Regional Government about damage to crops, including vineyards, caused by the Azores Woodpigeon on some of the Azorean islands.

No evidence for spatial variation in predation risk following restricted-area fox culling

BackgroundPredation and predator abundance may significantly affect bird populations, especially ground nesting species, because nest predation is often the major cause of nest failure. Predator control by means of culling is frequently employed to benefit threatened prey species or to increase the abundance of small game species for hunting. The red fox (Vulpes vulpes), a generalist mesopredator of global relevance, is a major target of predator control. Commonly, in central Europe, red fox culling efforts intended to benefit prey species remain restricted to small areas. It is unclear, however, whether such restricted-area culling effectively lowers predation risk at a site or whether red fox abundance is more important than culling in shaping predation risk. We conducted an experiment using 273 camera supervised artificial nests at multiple study sites in clusters of hunting concessions with or without targeted fox culling in a fragmented montane forest landscape in Germany.ResultsUsing generalized additive models, we assessed whether incentivized recreational culling of red foxes was associated with local reductions in an index of predation risk and fox occurrence probability, or whether both were explained by red fox abundance instead. Final models indicated that restricted-area culling of red foxes was not associated with local reductions in predation risk, nor lower probability of a fox sighting, even for the plots with the largest hunting bags. Predation risk at a plot instead appeared to be driven by variation in the abundance of red foxes in the landscape surrounding the plots. After accounting for fox abundance, we found no additional relationship of artificial nest predation risk with landscape configuration.ConclusionsOur results imply that the scale and intensity of predator control achieved by incentivized recreational hunting was ineffective at altering fox abundance patterns and associated predation risk. We thus find no evidence to support incentives for uncoordinated recreational red fox culling as a conservation measure.

Hail-induced nest failure and adult mortality in a declining ground-nesting forest songbird

ABSTRACT Natural catastrophes are known to impact wildlife populations, however opportunities to directly measure the demographic effects associated with such events are rare. Given the projected i...

Breeding ecology and causes of nest failure in the Indian Skimmer Rynchops albicollis

ABSTRACTCapsule: The breeding success of the Indian Skimmer Rynchops albicollis in eastern India is significantly reduced by human activities at the breeding sites.Aim: To investigate the breeding ecology of Indian Skimmer and factors affecting breeding success along the Mahanadi River in eastern India.Methods: A total of 230 Indian Skimmer nests were monitored in 2017 and 2018. Population, breeding phenology, clutch size, egg dimensions and factors affecting breeding success rates were determined.Results: Indian Skimmers arrived at the breeding sites during January–February followed by breeding activities during March–May. On a small scale, nests were more likely to be closer to water and ground vegetation than expected by chance, probably as mitigation against hot afternoon temperatures. Hatching success rate was higher (72.27%) in 2017 and chick survival rate was higher (33.15%) in 2018. Factors that affected breeding success were flooding, nest desertion, egg collecting by humans, predation and trampling.Conclusion: The breeding success rate of Indian Skimmer could be increased by protecting the breeding sites and minimizing disturbances through community awareness.

Breeding in the gray-headed tody-flycatcher (Aves: Tyrannidae) with comments on geographical variation in reproductive traits within the genus Todirostrum

ABSTRACTThe gray-headed tody-flycatcher Todirostrum poliocephalum is a passerine endemic to the Atlantic Forest of Brazil. We describe the nest and nesting behaviour of this species and investigate geographical variation in breeding traits in the genus using data from the literature, museum collections, and citizen science projects. We located 21 nests of the gray-headed tody-flycatcher, 13 of which we monitored. Nest height above the ground averaged 3.3 ± 3.4 m (n = 21). Nests were built over a 16.8 ± 5.6-day period (n = 6) by both adults. Clutch sizes ranged from two to three eggs, with a mean of 2.9 ± 0.3 eggs (n = 10). Eggs measured 16.6 ± 0.5 × 12.0 ± 0.5 mm (n = 23) and weighed 1.1 ± 0.1 g (n = 19). Mean incubation period was 17 days (n = 3) and mean nestling period was 15.5 days (n = 2). Apparent reproductive success was 30.8%, with predation being the primary cause of nest failure (46.1%). Mayfield’s reproductive success was 25.9%, and daily survival rates for eggs and nestlings were 0.957 and 0.971, respectively. Clutch sizes increased with latitude, but temperature and precipitation seasonality had very low importance in explaining clutch size variation.

Breeding biology of the Helmeted Manakin Antilophia galeata in an ecotone between the Atlantic Forest and the Cerrado

Manakins (Pipridae) are well-known by their promiscuous mating system. Nonetheless, scarce evidence suggests that the Helmeted Manakin Antilophia galeata, the only dichromatic manakin widely distributed in the South American Cerrado, is monogamic. We studied the breeding biology of the Helmeted Manakin in the state of Minas Gerais, southeastern Brazil. We found 17 nests, which are built in the forest undergrowth (usually below 3 m height). Nests are a cup attached by its top lip usually in the angle of a forked branch. The nest attachment zone is made mostly of spider silk. The structural zone is constructed with dry broad leaves, leaf petioles and horsehair fungus, which were bind together by a considerable amount of spider silk. The outer (decorative) zone is made with some hanging dry broad leaves, frequently forming a tail. Clutch size is always two (n = 12), and eggs are long oval, with a ground color in different shades of beige, marked with irregular spot, blotches and, sometimes, streaks ranging from light to dark brown. Mean eggs measurements were 23.9 x 16.3 mm (n = 14), weighting 3.3 g (n = 10). Eggs are laid once each day and hatching is synchronous. Females are the sole responsible for nest building (which usually took 10 days), incubation (18.5 days), and nestling care (18.3 days). The simple percentage of successful nests (n = 11) was 27% and predation was the main cause of nest failure. The breeding season extends from the second half of August to the first half of January. Renesting after loss of a first clutch is a common strategy and we recorded up to three nesting attempts for a single female. We present evidence that the Helmeted Manakin is promiscuous, as usual for a dichromatic manakin.

Interactions between Pied crows Corvus albus and breeding White-backed vultures Gyps africanus

African White-backed vultures Gyps africanus are Critically Endangered, mainly due to mortality from poisoning, but the species also exhibits variable breeding productivity that may partially be explained by nest failure due to predation. Pied crows Corvus albus have been implicated as nest predators, but because there is no evidence linking Pied crows to low breeding productivity of White-backed vultures, we used a combination of dummy eggs (n = 14) and camera traps on active nests (n = 10), to investigate what species visit White-backed vulture nests (both active and abandoned) and predate on their eggs. We recorded 47 egg predation events, of which 37 (79%) were attributable to Pied crows, while other predators (unidentified large raptors, White-backed vultures and Vervet monkeys) were recorded interacting with eggs 5 times in total; mobbing by Pied crows of incubating vultures increased the probability vultures would abandon their nest but crows did not eat abandoned eggs as soon as they were available. Further studies are needed across a wider range of vulture breeding areas to contextualise these findings both in terms of breeding productivity and the significant risks of mortality faced by vultures from poisoning and other threats.

Direct and indirect effects of ungulates on forest birds’ nesting failure? An experimental test with artificial nests

Increasing deer and wild boar populations in North America and Western Europe are suspected of threatening low-nesting forest birds. Ungulates may directly affect these birds by predating eggs or chicks, or indirectly attract other mammalian or avian predators or reduce nesting site availability and habitat quality. To test some of these various mechanisms in two French forests, 528 artificial nests, 77 of which (14.6%) were monitored with camera traps, were set up in 44 plots which were either unfenced or fenced to respectively include or exclude ungulates. We used generalized linear mixed models to relate the nest failure rate to indices of plot frequentation by ungulates and other nest predators, to vegetation structure and to local bird community richness indices. Nest failure rate was significantly higher in the unfenced plots (39%) than in the fenced plots (32%) but this was related neither to red deer nor to wild boar frequentation of the plots. Furthermore, levels of frequentation for other mammalian and avian predators tended to be positively correlated to ungulate presence but not to nest failure rate. Nest failure rate depended on both nest height and shrub cover: nests on the ground (31% failure rate) were less predated or disturbed than nests in low shrubs (41% failure rate). Nests surrounded by low shrub cover experienced a slightly higher predation risk. We conclude that ungulates have a limited influence on nest failure for low-nesting forest birds; in particular, they seem to contribute very little to egg predation compared to other predators.

Reduction in meso‐mammal nest predators improves northern bobwhite demographics

ABSTRACTNest predation is the major cause of nest failure in northern bobwhites (Colinus virginianus; i.e., bobwhites). Control of mid‐sized mammalian nest predators (i.e., meso‐mammals) is often conducted to increase reproductive success on lands managed for bobwhites. Nest predation by meso‐mammals, however, is only one part of a complex predator‐prey trophic system. There is limited understanding of the effect of nest predators on bobwhite demographics, which creates uncertainty about the efficacy of nest predator control. We quantified demographic effects on bobwhite populations from reducing meso‐mammals on 4 study areas managed for bobwhites in northern Florida and southwestern Georgia, USA, during 2000–2006. After 1 year of pre‐treatment monitoring (2000), we reduced meso‐mammal nest predator abundance through trapping over 3‐year intervals, March to September, on 2 sites using a crossover design. Efficacy of trapping was demonstrated by a 43% reduction in scent station visitation rates of meso‐mammals. Meso‐mammal control increased all demographic metrics including a 30% increase in nesting propensity, a 10% increase in nest success, and a 43% increase in chicks produced. Despite significant regional variation in breeding season survival rates, this equated to an average 18% increase in autumn density on trapped sites. Decision‐makers should weigh the tradeoffs between bobwhite population goals and costs of meso‐mammal control, where those that value maximum bobwhite density and reduced annual variation should likely implement control of meso‐mammals. © 2019 The Wildlife Society.

Impact of human activities on the reproduction of Hooded Vultures Necrosyrtes monachus in Burkina Faso

During the last decades, the critically endangered Hooded Vulture Necrosyrtes monachus has strongly declined across its African range. Although direct persecution has been suggested as a major cause of this decline, little is known about the impact of humans on reproductive output in West Africa. We studied the impact of human activities on the reproductive output of Hooded Vultures in the Garango area of Burkina Faso. Twenty and 56 nesting attempts were monitored, respectively, during the breeding season in 2013/14 and 2014/15, to determine reproductive success and identify causes of nest failure. Annual breeding success varied between 0.68 and 0.71 chicks fledged per breeding pair per year and productivity was assessed at 0.57 chicks fledged per territorial pair in 2014/15. The main threats imposed by humans were poaching of eggs, chicks and collection of nest materials, leading to 20% (13 out of 64 breeding attempts) of nest failures over the two years. An additional important reason for nest failure was the pruning and (partial) cutting of nest trees. Despite this high level of human interference, we found that Hooded Vulture nest success increased with proximity to human settlements, probably because breeding vultures benefit from protection by people against persecution and disturbance.

Mass-breeding by Hoary-headed Grebes Poliocephalus poliocephalus at Lake Bathurst, New South Wales

During surveys of the waterbirds of the Lake Bathurst wetland system on the Southern Tablelands of New South Wales, near Canberra (Australian Capital Territory) in most months from 1980 onwards, Hoary-headed Grebes Poliocephalus poliocephalus were found breeding on only six occasions. Nests were built along islands that formed only when Lake Bathurst and the neighbouring Southern Morass reached specific water depths. At higher and lower water levels, Grebes were present but did not breed. The maximum number of nests in a season was 985, much greater than any reported in the literature, but young were produced in only three seasons. Nest failures resulted from falling water levels, heavy rain (and associated rise in water level) or a wind-induced temporary rise in water level. Partial reflooding of the lake triggered late nesting, in April, but the nests were abandoned as the water level fell. High mobility, congregating at refilling wetlands and attempts to nest late in the season by this species may be responses to the ‘boom and bust’ scenario of inland wetlands.

Does the vicinity of the Black-Headed Gull colony (Chroicocephalus ridibundus) increase the breeding success of the Common Tern (Sterna hirundo) on the islands of the middle Vistula?

We conducted our study in the Common Tern colony (STH) located on an island in the middle Vistula River course, at the height of the city of Dęblin (km 393–394 of the waterway), in 2017. Our goal was to investigate some aspects of the biology and reproductive ecology of this species. Due to the fact that STH breeds both in single-species as well as in two- or multi-species colonies, in associations with Little Terns (Sternula albifrons), Black-Headed Gulls (Chroicocephalus ridibundus) (LAR) and/or Mew Gulls (Larus canus), we wanted to investigate whether the neighborhood of other species (in this case LAR) affected hatching success and chick survival in STH. Our results clearly show that the presence of breeding terns in the neighborhood of the LAR colony was not accidental and/or caused by the lack of space on the island and/or the possibility of nesting elsewhere. The height of nesting site, type of nesting habitat, clutch size, mean egg volume and mean egg mass of these STH pairs did not differ significantly from those that formed a single species colony, on the same island but several hundred meters away. However, STH nests in the neighborhood of the LAR colony were established much earlier and both the hatching success and chick survival of STH during the early-chick stage were twice as high. Thus, we can conclude that the LAR colony could provide an effective protection against predation of crows, magpies and gulls, dangers which accounted for the vast majority of STH nest failures in the year of our study.

Adjustment of total activity as a response to handicapping European starlings during parental care

Parental care is widely assumed to be costly, and life-history theory predicts that individuals that invest more in parental care should benefit in terms of number of offspring produced but that increased parental care might come at a cost in terms of decreased future fecundity and/or survival. However, the notion that parents that work ‘harder’, commonly measured by the rate at which parents visit the nestbox to provision their chicks, produce more, fitter chicks is surprisingly poorly supported. One potential reason for this apparent lack of relationship between measured workload during parental care and breeding productivity is that nest visit rate does not provide a good measure of foraging effort. Here, we used an automated radiotelemetry system to measure activity of individual female European starlings, Sturnus vulgaris, during breeding, combined with a handicapping experiment (combination of radiotransmitters and wing clipping) and measures of foraging metrics, current breeding productivity, future fecundity and return rate. Handicapping decreased current breeding success due to higher abandonment and nest failure, but among successful birds (fledging ≥ 1 chick) there was no effect of handicapping on brood size at fledging for the current breeding attempt. Handicapping decreased future fecundity, the probability of initiating a second brood, and return rate, but there was no evidence for additive costs of reproduction in wing-clipped females. Handicapping had no effect on provisioning rate but automated tracking data showed that, during chick rearing, wing-clipped females had 22% lower activity compared to females with radios only. Our data provide an explanation for the often contradictory effects of handicapping reported on reproductive effort and costs of reproduction: individuals can use behavioural flexibility – decreasing overall activity while maintaining provisioning rate – along with changes in mass and nestling diet to mitigate putative effects of increased workload imposed by handicapping.