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Knowledge of breeding success is essential for conservation, as it is required for monitoring populations and survival trends. Seabird reproductive success can be negatively affected by prey availability, marine‐based stochasticity, extreme weather events, individual breeders' performance and direct threats such as disease, predation and fisheries interactions.The endangered yellow‐eyed penguin (Megadyptes antipodes) is declining in mainland New Zealand, however, little is known about its breeding success in the subantarctic where the majority of the species breeds.Yellow‐eyed penguin breeding success data were collected from a total of 167 nests on subantarctic Enderby Island, Auckland Islands, New Zealand, from the 2015 to 2017 breeding seasons. This included egg and chick mortality and fledging rates, plus a wider sample of the fledgling condition of 276 chicks.Fledging success was higher than in mainland New Zealand in some years, although chicks were smaller and lighter on average, highlighting the need for more information on juvenile survival probabilities in the subantarctic.Breeding success measures were similar in 2015 and 2016, but a large egg mortality in 2017 caused a significant reduction in breeding success that year. Such variability requires more investigation into the correlates of breeding success, including possible stressors such as foraging success, adverse weather and environmental effects, and pathogens.These results demonstrate the need for ongoing monitoring of yellow‐eyed penguin breeding success across the subantarctic in order to establish baselines for normal variation and to determine whether anthropogenic (manageable) factors may be contributing to low productivity.This research highlights an important consideration for endangered species conservation; that breeding success may not be consistent over time, or across a species' entire range. Additional monitoring of all breeding populations should be carried out to ensure up‐to‐date information is available to inform conservation management decisions for the species. [ABSTRACT FROM AUTHOR]

Pharmacological and nutritional benefits of plant leaf extracts can be harnessed to address the problem of poor chick quality, performance and high mortality, which affect both hatchery and farm managers. This study sought to evaluate the in ovo effect of Soursop leaf extract (SLE) on the hatching and post-hatch performance of Noiler chicks. A total of 640 fertile eggs were randomly distributed into four groups of five replicates: (0.25 µg SLE), (0.5 µg SLE), (0.75 µg SLE) and a non-injected control. On day 18 of incubation, 0.2 ml of SLE was injected into the airspace of the eggs. At hatch, embryonic mortality, hatchability, and chick quality were evaluated. Hatched chicks were reared to assess feed intake, weight gain, feed conversion ratio (FCR) and mortality. Results showed no significant difference (p > 0.05) in embryonic mortality, hatchability and weight gain among the treatment groups. Chick weight and feed intake were significantly higher (p

Sex allocation theory predicts that parents should adjust their brood sex ratio to maximize fitness returns in relation to parental investment. Adaptive adjustment of sex ratio may be driven by differential costs of rearing sons and daughters or differential benefits of investing limited resources into offspring of different sex. In both cases, possible sex ratio bias should depend on parental condition. For sexually dimorphic birds with males larger than females, sons may be less likely to fledge since they are more vulnerable to food shortages or because they have impaired immunocompetence due to higher testosterone levels. Poor condition females should thus overproduce daughters to minimize possible reproductive failure. We manipulated the number of eggs laid and the amount of food available to laying females to induce differences in the condition in 2 gull species differing in sexual size dimorphism. In the Black-headed Gull (Chroicocephalus ridibundus), sexual size differences are marginal; but in the Mew Gull (Larus canus), males are 11% larger. In both species, females forced to lay an additional egg (presumed in worse condition) overproduced daughters, whereas females receiving supplemental food before laying (presumed improved condition) overproduced sons. This sex ratio skew was larger in Mew Gull, a species with larger size dimorphism. Chick immunocompetence at hatching was unrelated to sex, being higher in broods of fed mothers and lower for chicks hatched from last-laid eggs. Chick survival between hatching and day 5 post-hatch was positively related to their immunocompetence, but chicks from last-laid eggs and males of Mew Gull, the more dimorphic species, survived less well. Results indicate that costs of raising larger sex offspring coupled with parental condition shape brood sex ratio in populations studied. Adaptive brood sex ratio adjustment occurs mostly before egg laying and includes differential sex allocation in eggs depending on the probability of producing a fledged chick. [ABSTRACT FROM AUTHOR]

Crested screamers, a unique, mainly terrestrial avian species native to South America, are known to have a markedly high chick mortality rate in captivity, ranging from 61-94%; however, there is very limited information on this species’ natural history within the literature, and even less about common diseases that affect them. Four captive-born crested screamer chicks (Chauna torquata) at a U.S. zoological institution died acutely from different causes over the course of two and a half months. Although a hands-off approach was initially taken, each chick became acutely weak on exhibit and medical intervention was deemed necessary, but proved unsuccessful in all cases. Necropsy results of the chicks revealed various causes of death, including acute E. coli colitis, aspiration pneumonia complicated by concurrent gastrointestinal Candidiasis, severe dehydration and emaciation, and acute amoebic gastroenteritis. No direct associations were found between these deaths and diet or husbandry; however, the limited literature on this topic suspects inadequate husbandry and immunosuppression to be the greatest cause of chick mortality in this species. The cases presented here are consistent with this hypothesis, but further exemplify the limited knowledge of this species and how to optimize their survivability and proliferation in captivity.

In the context of environmental change, determining the causes underpinning unusual mortality events of vertebrate species is a crucial conservation goal. This is particularly true for polar and sub-polar colonial seabirds, often immunologically naïve to new and emerging diseases. Here, we investigate the patterns of black-browed albatross (Thalassarche melanophris) chick mortality events unrelated to predation recorded between the 2004/05 and 2019/2020 breeding seasons in four colonies across the species range in the Falklands. The prevalence of these mortality events was highly variable across years, causing the death of between 3 and 40% of all chicks in the studied plots. With few exceptions, mortality was patchily distributed. Using clustering methodologies, we identified the spatio-temporal mortality clusters based on the nest locations and chick death date. Using generalised linear models and generalised additive mixed-effects models we found that chicks nearer the first mortality event were predicted to die before those in more distant nests. The probability of death increased with age and was highest for chicks close to nests where a chick had died previously. Our findings, along with the symptoms consistently exhibited by most deceased chicks in the study, strongly suggest the prevalence of a widespread infectious disease, potentially with a common aetiology, both in areas with regular and with very rare human presence. Understanding the causes driving these disease-related mortality events, which seem different from the outbreaks documented in the literature, is a conservation priority for the Falklands black-browed albatross population, which comprises over 70% of the species global population. [ABSTRACT FROM AUTHOR]

The poultry industry has recently undergone transitions into antibiotic free production, and viable antibiotic alternatives, such as probiotics, are necessary. Through in ovo probiotic inoculation, beneficial microflora development in the gastrointestinal tract may occur prior to hatch without negatively impacting chick performance. Therefore, the objective of the present study was to observe the impacts of the injection of probiotic bacteria individually or combined into fertile broiler hatching eggs on hatch and live performance characteristics. A total of 2,080 fertile broiler hatching eggs were obtained from a commercial source. On day 18 of incubation, 4 in ovo injected treatments were applied: 1.) Marek's Disease (HVT) vaccination, 2.) L. animalis (∼106 cfu/50μl), 3.) E. faecium (∼106 cfu/50μl), and 4.) L. animalis + E. faecium (∼106 cfu & ∼106 cfu/50μl each). On day of hatch, hatchability and hatch residue data were recorded. A portion of male chicks from each treatment were placed in a grow-out facility for a 21 d grow-out (18 chicks/pen × 10 pens/treatment = 720 male chicks) with a corn and soy bean meal-based diet without antibiotics or antibiotic alternatives. Performance data and gastrointestinal samples were collected on days 0, 7, 14, and 21. Results indicated no differences in all hatch parameters between treatments (P > 0.05) except for % pipped, where the L. animalis treatment had lower % pipped eggs compared to the HVT control and E. faecium treatments (P = 0.04). No differences were observed in body weight gain or mortality (P > 0.05). Probiotic treatments altered gastrointestinal tissue length, weight, and pH. This resulted in all in ovo injected probiotic treatments increasing feed conversion ratio (FCR) from days 7 to 14 as compared to the control (P = 0.01). Differences in FCR were not observed in any other week of data collection (days 0 to 7, 14 to 21, or 0 to 21; P > 0.05). Although probiotics altered live performance from days 7 to 14, these data suggest that in ovo inoculations of L. animalis and E. faecium in combination are viable probiotic administration practices that potentially improve hatch characteristics and gastrointestinal tract development. [ABSTRACT FROM AUTHOR]

The aim of this research was to study the factors affecting hatchability, percentage of egg weight loss during incubation, early embryonic mortality, and chick mortality in the first seven days of life in the field. This study was performed on 20,817,600 hatching eggs originating from 7 different breeder flocks. The factors responsible for variability of investigated traits were the following: genotype (ROSS 308, ROSS PM3), hen age (25 to 30, 31 to 45, 46 to 50, and 51 to 60 wk), egg storage time (0 to 13 d), and setter and hatcher type (Digital, Airstreamer, Vision, Focus, Biostreamer), which were determined using the classification tree technique. Statistical calculations were performed using R software, version 3.4.3. Moreover, 2-way analysis of variance followed by Duncan's multiple comparison test was performed. The breeder flock age and egg storage time were the most important factors responsible for variability in the percentage of fertile hatchability; however, setter and hatcher type also affected the level of this trait. The highest hatchability was observed for eggs laid by hens aged 31 to 50 wk and stored up to 6 d. Genotype was the most important determinant of the percentage of egg weight loss and that Ross 308 eggs lose less weight when compared to Ross PM3 ones. Egg storage time was the most important factor, which affected early embryonic mortality. The present study has shown that the 2 main factors, i.e. breeder flock age and egg storage time, that affected hatchability have also influenced chick mortality. Moreover, it was found that both hatcher and setter type affected chick mortality in the first 7 d of life. The importance of this research lies in the fact that besides showing the most important factors affecting hatching process, we were also able to suggest how to adjust the management decisions at commercial hatcheries in order to increase production results in different egg sets, which vary in respect of breeder flock age, egg storage time, setter, and hatcher type and genotype. [ABSTRACT FROM AUTHOR]

Crested screamers, a unique, mainly terrestrial avian species native to South America, are known to have a markedly high chick mortality rate in captivity, ranging from 61% to 94%; however, there is very limited information on this species' natural history within the literature, and even less about common diseases that affect them. Four captive-born crested screamer chicks (Chauna torquata) at a U.S. zoological institution died acutely from different causes over the course of 2.5 months. Although a hands-off approach was initially taken, each chick became acutely weak on exhibit and medical intervention was deemed necessary, but proved unsuccessful in all cases. Necropsy results of the chicks revealed various causes of death, including acute Escherichia coli colitis, aspiration pneumonia complicated by concurrent gastrointestinal Candidiasis, severe dehydration and emaciation, and acute amoebic gastroenteritis. No direct associations were found between these deaths and diet or husbandry; however, the limited literature on this topic suspects inadequate husbandry and immunosuppression to be the greatest cause of chick mortality in this species. The cases presented here are consistent with this hypothesis, but further exemplify the limited knowledge of this species and the need to optimize their survivability and proliferation in captivity. [ABSTRACT FROM AUTHOR]

Pharmacological and nutritional benefits of plant leaf extracts can be harnessed to address the problem of poor chick quality, performance and high mortality, which affect both hatchery and farm managers. This study sought to evaluate the in ovo effect of Soursop leaf extract (SLE) on the hatching and post-hatch performance of Noiler chicks. A total of 640 fertile eggs were randomly distributed into four groups of five replicates: (0.25 µg SLE), (0.5 µg SLE), (0.75 µg SLE) and a non-injected control. On day 18 of incubation, 0.2 ml of SLE was injected into the airspace of the eggs. At hatch, embryonic mortality, hatchability, and chick quality were evaluated. Hatched chicks were reared to assess feed intake, weight gain, feed conversion ratio (FCR) and mortality. Results showed no significant difference ( p  > 0.05) in embryonic mortality, hatchability and weight gain among the treatment groups. Chick weight and feed intake were significantly higher ( p  < 0.05) in SLE groups, while FCR and mortality were significantly lower ( p  < 0.05) in SLE groups. It was concluded that in ovo injection of SLE improved chick weights, feed conversion and livability of Noiler chicks., Competing Interests: We the authors (T.T. Kuka, B. Bakoma, F.C. Kuka and B. Adjei-Mensah) of the accompanying article, write to declare that there is no personal or professional conflict of interest with our work., (© 2023 The Authors.)

A retrospective study of mortality and neonatal treatment for 975 Attwater's prairie chickens (Tympanuchus cupido attwateri) was conducted from 2009–2015. Gross necropsy, histopathology, and medical records for chicks less than 8 wk of age at the Houston Zoo were reviewed and summarized. The total mortality rate was 36% (n = 352). Yolk sac infection was the most common cause of death (21%; n = 73) followed by maladaptation (19%; n = 68), musculoskeletal abnormalities (19%; n = 66), necrotic enteritis (13%; n = 44), and mucoid enteritis (11%; n = 39). Gavage feeding of a highly digestible formula was associated with a higher proportion of necrotic enteritis and a reduced occurrence of both mucoid enteritis and maladaptation. Meloxicam administration had a significantly reduced incidence of mucoid enteritis. Survival past 10 days of age, prevention of neonatal bacterial infection, and supportive treatment with meloxicam are important factors to increase chick survival and improve captive breeding success for Attwater's prairie chickens. Gavage feeding of a diet low in digestible carbohydrates has the potential for reducing disease due to necrotic enteritis in this species. [ABSTRACT FROM AUTHOR]

Translocation of captive-reared animals is widely used as a tool for endangered species recovery. Frequently, translocated populations have relatively low initial productivity, requiring management intervention. A translocated population of whooping cranes Grus americana in centralWisconsin is such a case. We examined chickmortality for this population and used daily chick survival rates as our response variable to model several parameters including phenology, chick age, energetics and parent age and experience. We also developed and evaluated adoption techniques using sandhill cranes Grus canadensis to mitigate the effects of high chick mortality and increase the probability of fledging.Our results illustrate the challenges that translocated populations can face as they encounter novel breeding conditions. We found that whooping crane daily chick survival was relatively low and most mortality events occurred within the first 20 days. Our results indicated that variables related to age of the parents as well as the pair's previous chick rearing experience were useful for predicting daily chick survival. We found that sandhill crane foster parents readily accepted replacement chicks. We also demonstrated adopted chicks acceptance of foster parents and that the chicks' source (captive-born vs wild-born) did not affect success of the adoption. Chick adoption provides several management options that could be used to bypass the period when chicks experience the greatest mortality. Reducing chick mortality and developing techniques to increase the number of fledged chicks is paramount for whooping crane recovery as well as the recovery of other endangered bird species. [ABSTRACT FROM AUTHOR]

This article discusses a study which examined the causes of death of chicks and the effects of intensive, local predator control on chick production in Norway from 1997 to 2004. Following the initiation of intensive local predator control, the study found that 73 percent of chicks died due to predation and 17 percent was research-related deaths. It also showed that 10 percent of chicks died of other natural causes than predation. The study concluded that predator control had no measurable effect on the production or survival of chicks.

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The aim of this study was to estimate the importance of factors affecting the breeding success of the grey heron ( Ardea cinerea) in three colonies in the northern Poland (Mosty, Kiersity and Kąty Rybackie), differentiated in population size, habitat type and feeding areas used by birds. The highest mean number of fledglings (39–51 days old) per nest in 2000–2002 combined was recorded at Kąty Rybackie (3.2±0.91 SD). Lower values were recorded at Kiersity (2.5±1.11) and Mosty (2.8±1.20). Breeding success increased with the size of the heronry ( r7=0.77, P<0.05) and was the highest in the biggest, at Kąty Rybackie (716–879 nests). In the studied colonies, the number of feeding visits was the most important factor affecting breeding success. At Kąty Rybackie and Kiersity, chick mortality significantly decreased with increasing numbers of feeding visits per nest. The highest breeding success was recorded in the colonies with feeding areas situated nearby (Kąty Rybackie and Mosty). Siblicide was also a very important reason of chick mortality in those colonies (54% and 32% chicks died in nests where sibling aggression was observed). Other factors, independent of the level of feeding, like predation, human disturbance, weather condition and experience of parent birds, seem to be of negligible importance. [ABSTRACT FROM AUTHOR]

The population decline of the nominate lesser black-backed gull Larus fuscus fuscus in the Gulf of Finland (northern Baltic) is caused by an exceedingly high chick mortality due to diseases. The chick diseases include degeneration in various internal organs (primarily liver), inflammations (mainly intestinal), and sepsis, the final cause of death. The hypothesis of starvation causing intestinal inflammations (leading to sepsis) was tested by attempting to reproduce lesions in apparently healthy herring gull L. argentatus chicks in captivity. The herring gull chicks were provided a similar low food-intake frequency as observed for the diseased chicks in the wild. However, empty alimentary tract per se did not induce the intestinal inflammations and therefore, inflammations seem to be innate or caused by other environmental factors in the diseased lesser black-backed chicks. They had very high concentrations of PCB in their liver; but the concentrations were not significantly higher than those of the healthy herring gull chicks, indicating a common exposure area for both species (i.e. the Baltic Sea). When compared to NOEL and LOEL values for TEQs in bird eggs our TEQ levels clearly exceed most or all of the values associated with effects. Compared with published data on fish-eating waterbirds, the DDE concentrations in the diseased lesser black-backed chicks were well above the levels previously correlated with decreased reproduction, while the residues in apparently healthy herring gulls were below those levels. The DDE/PCB ratio in lesser black-backs was significantly elevated, indicating an increased exposure to DDTs as compared with most other Baltic and circumpolar seabirds. The possible exposure areas of DDT in relation to differential migration habits of the two gull species are discussed. [Copyright &y& Elsevier]

We used video cameras over 5 years to quantify causes of mortality at 172 nests of three species of ground-nesting birds that nest on braided riverbeds of the Upper Waitaki Basin, South Island, New Zealand. The species were banded dotterels Charadrius bicinctus (n=114), black stilts Himantopus novaezelandiae (n=23), and black-fronted terns Sterna albostriata (n=35). Of 77 recorded lethal events (excluding four desertions caused by us), 66 involved deaths of only eggs, and 11 involved deaths of adults and/or chicks, and/or eggs. The main predators were cats Felis catus, hedgehogs Erinaceus europaeus, and ferrets Mustela furo, which were responsible for 43, 20, and 18% of lethal events, respectively. Cats were the only predator species to take adult birds. We recorded only two avian predations: a harrier Circus approximans took a chick and a hatching egg from one nest, and an Australian magpie Gymnorhina tibicen ate chicks at one nest. Other causes of mortality were incubating adult birds, floods, and sheep Ovis aries. Each accounted for <4% of lethal events. Ninety percent of visits (151 of 168) by predators or potential predators happened between sunset and sunrise. We found no evidence that video cameras or infra-red lighting influenced predation rates during 2 years of testing for such effects. [Copyright &y& Elsevier]

The recently hatched chicks' umbilicus provides a pathway for the introduction of pathogenic microorganisms. Consequently, sanitation of hatcher basket is crucial to the future success of the chick. The design of this study was to examine the effects of two hatcher basket wash systems on microbial loads and subsequent 7 d chick mortality. Treatment 1 consisted of a single stage wash system and treatment 2 was a Multi-stage wash system. On sampling days, 10 hatcher baskets randomly selected off the chick processing line were individually swabbed pre-washing. A 5.08 cm2 templet placed in the lower left hand corner of each hatcher basket ensured accurate sampling. Following pre-wash sampling each basket was labeled, placed into the wash system, and recovered immediately post washing. A second templet placed in the same location as the first and a post wash swab collected. Samples were collected for 10 non-consecutive days. Following each collection day, each swab was plated on a 3M-Petrifilm Count Plate and allowed to incubate for 48 h at 39.44oC. Following incubation, plates were read to determine total plate count (TPC per cm2). There were no significant (P.05) at either the prewash (993 vs 595) or post wash (38 vs 58). There were no significant differences (P >.05) in 7 day mortality between treatment 1 vs 2 (0.95% vs 1.12%). In conclusion, both wash systems were effective in reducing microbial loads. [ABSTRACT FROM AUTHOR]

The recently hatched chicks' umbilicus provides a pathway for the introduction of pathogenic microorganisms. Consequently, sanitation of hatcher basket is crucial to the future success of the chick. The design of this study was to examine the effects of two hatcher basket wash systems on microbial loads and subsequent 7 d chick mortality. Treatment 1 consisted of a single stage wash system and treatment 2 was a Multi-stage wash system. On sampling days, 10 hatcher baskets randomly selected off the chick processing line were individually swabbed pre-washing. A 5.08 cm2 templet placed in the lower left hand corner of each hatcher basket ensured accurate sampling. Following pre-wash sampling each basket was labeled, placed into the wash system, and recovered immediately post washing. A second templet placed in the same location as the first and a post wash swab collected. Samples were collected for 10 non-consecutive days. Following each collection day, each swab was plated on a 3M-Petrifilm Count Plate and allowed to incubate for 48 h at 39.44oC. Following incubation, plates were read to determine total plate count (TPC per cm2). There were no significant (P.05) at either the prewash (993 vs 595) or post wash (38 vs 58). There were no significant differences (P >.05) in 7 day mortality between treatment 1 vs 2 (0.95% vs 1.12%). In conclusion, both wash systems were effective in reducing microbial loads. [ABSTRACT FROM AUTHOR]