Daily Survival Research Articles

Multi-scale nest survival analysis suggests new cavities improve nest success for the Green-barred Woodpecker, but not the Campo Flicker, in a threatened woodland of Argentina

Abstract Understanding factors affecting nest survival of woodpeckers in threatened landscapes is a key tool for land managers, particularly when conservation depends on public policies. However, information of Neotropical woodpeckers breeding in southern temperate forests is noticeably sparse despite the worrying conservation status of these ecosystems and woodpeckers’ key role as cavity providers. Our objective was to assess the relationship between tree cavity features, vegetation structure, and landscape configuration on the nest survival of the Green-barred Woodpecker (Colaptes melanochloros) and the Campo Flicker (C. campestris). We monitored nests of these woodpeckers during 3 breeding seasons from 2015 to 2018 in a woodland of east-central Argentina threatened by selective tree logging and soil material extraction. We recorded features that presumably influence nest survival at a micro-scale (cavity, cavity-tree features, and foliage cover around the cavity) and a macro-scale (forest cover and shape index within a 500-m circle around the nest). We did not find support for a relationship between daily nest survival rates (DSR) and cavity features, vegetation structure, or landscape configuration. However, new cavities were more successful than reused ones for the Green-barred Woodpecker. We also found a surprisingly high rate (~33% of nest failures) of nest abandonment for both species. Abandonment may be a factor regulating this population and causes of abandonment warrants further investigation. Given the importance of new cavities to the success of Green-barred Woodpeckers, our results indicate the preservation of medium-size trees (20 cm < diameter at breast height [DBH] < 50 cm) with wood softened by degradation processes (preferred by the species to excavate cavities) would facilitate persistence both of this woodpecker and the cavity nesting community. Effective audit of soil material extraction and controlled selective timber logging practices (including preservation of mature trees) in compliance with existing regulations could contribute to this type of habitat maintenance.

Women’s Practices of Everyday Life in the Conditions of the Ukrainian Village in the First Years of Post-War Reconstruction (1944-1947)

The purpose of article is to use the example of Zhytomyr Oblast and describe the daily survival practices of women collective farmers in the conditions of the reconstruction of the collective farm system and the famine of 1946-1947 and the peculiarities of their perception of those transformational processes, which they were witnesses and participants of.
 Scientific novelty. The topic of everyday life in the Ukrainian village in the period of late Stalinism is considered from the aspect of experience of Ukrainian collective farmers women for the first time in Ukrainian historiography.
 Conclusion. The core of the post-war reconstruction of the Ukrainian village was the restoration of the collective farm system. Given the changes in the demographic situation caused by the war and the German occupation of Ukrainian territories, women were the main mobilization resource for replenishing the ranks of collective farm workers. The memories of peasant women/peasants of Zhytomyr region provide grounds for the conclusion that in the period under study, the collective farm system had a distinctly discriminatory nature for women. Labor relations in the structure of the collective farm, which during the famine of 1946-1947 had a repressive character, had a dominant influence on the everyday lifestyle of the rural family.
 According to the stories of our respondents, in the period we studied, the responsibility for the survival of the family mostly rested on the woman-mother. In historiography, this status of hers is usually called ‘double burden’. There have been certain changes in the spatial and temporal dimensions of women’s everyday life. The woman had to combine hard work in the collective farm with work in the household and care and upbringing of children. During the famine of 1946-1947, women’s survival practices to some extent depended on her status: either she was a ‘widow’ (the breadwinner of the family) or ‘had a husband’ (responsibility for providing for the family was shared between spouses). In general, it can be confidently asserted that the strategies of everyday behavior of the peasants in the first years of post-war reconstruction had a clear imprint of gender-colored labeling.

Early nest initiation and vegetation density enhance nest survival in Wild Turkeys

Abstract The theory of adaptive habitat selection suggests resource selection by animals should reflect underlying quality, such that individual selection confers an adaptive advantage via increased fitness. Using resource selection functions and nest survival models, we demonstrated that visual obstruction at the nest site was adaptively significant but timing of nest initiation had the greatest effect on nest survival for eastern Wild Turkeys (Meleagris gallopavo silvestris). Predation risk is a selective pressure, and if individuals can perceive predation risk, they may respond by altering the selection of nest site characteristics based on prior experience. We evaluated patterns in nest site selection of 387 Wild Turkeys and the consequences of selection on reproductive success across the southeastern United States from 2014 to 2019. We monitored 549 nest sites and found that nest initiation date had the strongest effect on daily nest survival rates, wherein adult females at our earliest nest initiation date were ~4 times more likely to successfully nest than females at our latest nest initiation date. Selection of nest sites with greater visual obstruction also increased daily nest survival rates, and females were 1.17 (95% CI: 1.100–1.234) and 1.37 (95% CI: 1.258–1.486) times more likely to select sites for every 10-cm increase in visual obstruction and maximum vegetation height, respectively. Collectively, our results indicate that nest initiation date is likely the critical parameter driving Wild Turkey nest success, whereas vegetative conditions play a lesser role in influencing nest success. Females nesting earlier may be in better body condition and show increased nest attentiveness, which may mediate nest success more than vegetation conditions around nest sites. Our work indicates that increasing the reproductive success of Wild Turkeys may hinge on females being able to nest as early as possible within the reproductive season.

Biochemical response and production performance of spiny lobster Panulirus homarus seed reared with different shelter materials

Provision of shelters during nursery rearing of the spiny lobster Panulirus homarus seed is expected to reduce stress and generate higher production performance. In the present study, three types of shelter materials viz, polyvinyl chloride (PVC) pipes, polyethylene (PE) nets and concrete blocks with three replications were used as treatments. The results showed that pipe shelter was the best among three treatments with better yield, higher survival rates and lower stress level indications. Examination of haemolymph for total cholesterol, total protein, total haemocyte count (THC) and glucose showed that pipe shelter treatment exhibited the lowest stress response compared to the other treatments. In terms of lobster weight and carapace length, the application of pipe shelters resulted in the best growth of seeds. Furthermore, the highest daily weight gain and survival rate of 1.41±0.04 and 72.67±1.53% respectively were recorded in seeds reared in pipe shelter, while the lowest values were recorded in concrete block shelter.Keywords: Glucose, Lobster, Shelter, THC, Total cholesterol, Total protein

Effects of grazing strategy on facultative grassland bird nesting on native grassland pastures of the Mid-South USA.

Understanding how livestock grazing strategies of native warm season grasses (NWSG) can impact facultative grassland bird nesting can provide insight for conservation efforts. We compared pre and post treatment effects of rotational grazing (ROT) and patch-burn grazing (PBG) for facultative grassland bird species nest success and nest-site selection on NWSG pastures at three Mid-South research sites. We established 14, 9.7 ha NWSG pastures and randomly assigned each to either ROT or PBG and monitored avian nest-site selection and nest success, 2014–2016. We collected nesting and vegetation data in 2014, before treatment implementation, as an experimental pre-treatment. We implemented treatments across all research sites in spring 2015. We used a step-wise model selection framework to estimate treatment effect for ROT or PBG on avian nest daily survival rate (DSR) and resource selection function (RSF) at the temporal scale and within-field variables. Daily survival rates were 0.93% (SE = 0.006) for field sparrow (Spizella pusilla), 0.96% (SE = 0.008) for red-winged blackbird (Agelaius phoeniceus), and 0.92% (SE = 0.01) for indigo bunting (Passerina cyanea). Model support for PBG treatment and vegetation height were indicated as negative and positive influences for field sparrow DSR, respectively. Red-winged blackbirds’ DSR were negatively influenced by ROT while vegetation height positively affected DSR, and DSR for indigo bunting did not differ among treatments. Combined RSF models indicated nest-site selection for all species was positively related to vegetation height and only weakly associated with other within-field variables. We provide evidence that ROT and/or PBG effects vary by species for DSR for these three facultative grassland birds, and vegetation characteristics affected their nest-site selection in the Mid-South USA. A lack of disturbance in Mid-South grasslands can lead to higher successional stages (i.e., mix shrub-grassland), but some combination of ROT, PBG, and unburned/ungrazed areas can provide adequate nesting habitat on small pasture lands (∼1.8 –7.8 ha) for various facultative grassland birds and potentially offer the opportunity to simultaneously maintain livestock production and grassland bird nesting habitat.

A diagnosis model of parental care: How parents optimize their provisioning strategy in brood reduction?

Altricial birds often display biased preferences in providing parental care for their dependent offspring, especially during food shortages. During this process, such inflexible rules may result in provisioning errors. To demonstrate how parents optimize their provisioning strategies, we proposed a "diagnosis model" of parental care to posit that parents will undergo a diagnosis procedure to test whether selecting against some particular offspring based on phenotype is an optimal strategy. We tested this model in an asynchronous hatching bird, the Azure-winged Magpie Cyanopica cyanus, based on 10 years of data about demography and parental provisioning behaviors. Given their higher daily survival rates, core offspring (those hatched on the first day) merits an investment priority compared with their marginal brood mates (those hatched on later days). However, a marginal offspring also merited a priority if it displayed greater weight gain than the expected value at the early post-hatching days. Parents could detect such a marginal offspring via a diagnosis strategy, in which they provisioned the brood at the diagnosis stage by delivering food to every nestling that begged, then biased food toward high-value nestlings at the subsequent decision stage by making a negative response to the begging of low-value nestlings. In this provisioning strategy, the growth performance of a nestling became a more reliable indicator of its investment value than its hatching order or competitive ability. Our findings provide evidence for this "diagnosis model of parental care" wherein parents use a diagnosis method to optimize their provisioning strategy in brood reduction.

A Mark-Release-Recapture Study to Estimate Field Performance of Imported Radio-Sterilized Male Aedes albopictus in Albania.

The pathogen transmitting Aedes albopictus mosquito is spreading rapidly in Europe, putting millions of humans and animals at risk. This species is well-established in Albania since its first detection in 1979. The sterile insect technique (SIT) is increasingly gaining momentum worldwide as a component of area-wide-integrated pest management. However, estimating how the sterile males will perform in the field and the size of target populations is crucial for better decision-making, designing and elaborating appropriate SIT pilot trials, and subsequent large-scale release strategies. A mark-release-recapture (MRR) experiment was carried out in Albania within a highly urbanized area in the city of Tirana. The radio-sterilized adults of Ae. albopictus Albania strain males were transported by plane from Centro Agricoltura Ambiente (CAA) mass-production facility (Bologna, Italy), where they were reared. In Albania, sterile males were sugar-fed, marked with fluorescent powder, and released. The aim of this study was to estimate, under field conditions, their dispersal capacity, probability of daily survival and competitiveness, and the size of the target population. In addition, two adult mosquito collection methods were also evaluated: BG-Sentinel traps baited with BG-Lure and CO2, (BGS) versus human landing catch (HLC). The overall recapture rates did not differ significantly between the two methods (2.36% and 1.57% of the total male released were recaptured respectively by BGS and HLC), suggesting a similar trapping efficiency under these conditions. Sterile males traveled a mean distance of 93.85 ± 42.58 m and dispersed up to 258 m. Moreover, they were observed living in the field up to 15 days after release with an average life expectancy of 4.26 ± 0.80 days. Whether mosquitoes were marked with green, blue, yellow, or pink, released at 3.00 p.m. or 6.00 p.m., there was no significant difference in the recapture, dispersal, and survival rates in the field. The Fried competitiveness index was estimated at 0.28. This mark-release-recapture study provided important data for better decision-making and planning before moving to pilot SIT trials in Albania. Moreover, it also showed that both BG-traps and HLC were successful in monitoring adult mosquitoes and provided similar estimations of the main entomological parameters needed.

Lacticaseibacillus rhamnosus alleviates intestinal inflammation and promotes microbiota-mediated protection against Salmonella fatal infections

The fatal impairment of the intestinal mucosal barrier of chicks caused by Salmonella significantly resulting economic losses in the modern poultry industry. Probiotics are recognized for beneficially influencing host immune responses, promoting maintenance of intestinal epithelial integrity, antagonistic activity against pathogenic microorganisms and health-promoting properties. Some basic studies attest to probiotic capabilities and show that Lacticaseibacillus rhamnosus could protect intestinal mucosa from injury in animals infected with Salmonella Typhimurium. However, the mechanisms underlying its protective effects in chicks are still not fully understood. Here, we used the chick infection model combined with histological, immunological, and molecular approaches to address this question. The results indicated that L. rhamnosus significantly reduced the diarrhea rate and increased the daily weight gain and survival rate of chicks infected with S. Typhimurium. Furthermore, we found that L. rhamnosus markedly improved the immunity of gut mucosa by reducing apoptotic cells, hence effectively inhibiting intestinal inflammation. Notably, pre-treatment chicks with L. rhamnosus balanced the expression of interleukin-1β and interleukin-18, moderated endotoxin and D-lactic acid levels, and expanded tight junction protein levels (Zonula occluden-1 and Claudin-1), enhanced the function of the intestinal mucosal epithelial cells. Additionally, investigations using full-length 16S rRNA sequencing also demonstrated that L. rhamnosus greatly weakened the adhesion of Salmonella, the mainly manifestation is the improvement of the diversity of intestinal microbiota in infected chicks. Collectively, these results showed the application of L. rhamnosus against Salmonella fatal infection by enhancing barrier integrity and the stability of the gut microbiota and reducing inflammation in new hatch chicks, offering new antibiotic alternatives for farming animals.

Growth and survival rates of dispersing free embryos and settled larvae of pallid sturgeon (Scaphirhynchus albus) in the Missouri River, Montana and North Dakota

We released nearly 1.0 million 1-day post-hatch (dph) and 5-dph pallid sturgeon (Scaphirhynchus albus) free embryos in the Missouri River on 1 July 2019 and sequentially captured survivors at multiple sites through a 240-km river reach to quantify daily growth and survival rates during the early life stages. Genetic analysis was used to assign captured fish to released family lots and known ages. Growth rate was similar (0.74–0.75 mm day−1) between the 1- and 5-dph age groups during the 3–4-day dispersal period when water temperature averaged 16.8 °C. Daily survival rate was 0.64 during 1–4 dph for the original 1-dph age group and 0.80 during 5–7 dph for the original 5-dph age group. Total survival during free embryo dispersal (hatch to 9 dph) was estimated as 0.0437. The transition from dispersing as free embryos to settling as benthic larvae was verified for fish originally released as 5 dph. Growth of settled larvae was quantified with a Gompertz model through 75 dph (9 September; 112 mm) when water temperature was 18.8–21.0 °C in the rearing areas. Settled larvae had an estimated daily survival rate of 0.96, and estimated total survival during 9–75 dph was 0.0714. This study provides the first empirical survival estimates for pallid sturgeon early life stages in natural settings and is one of few studies reporting similar information for other sturgeon species. Applications of this work extend to pallid sturgeon restoration programs where population models are being developed to predict recruitment potential and population responses to river management alternatives.

Homeless Young People – Relationships and Risks of living on the Street

This article brings information about homeless young people as an alternative way of life from the point of view of their daily survival on the street. The aim of the paper is to present the results of qualitative research associated with the phenomenon of homeless young people and to understand their life on the streets in terms of creating some relationships, namely solidarity, a functioning group as a family and its mutual help or variability, and obstacles to changing this lifestyle. It also informs about the risks posed by the majority society, city police, robbery, including the search for the meaning of the day. It is important, but also in the interest of society as a whole, to provide qualified social help to this target social group and reduce the number of young people on the streets and successfully reintegrate them back into the majority society.

Le droit à la liberté de circulation des personnes à l’épreuve des mesures de lutte contre la pandémie de la Covid-19 en RDC

The Covid-19 pandemic is an unprecedented threat to health. Like other States, the DRC has taken unprecedented and exceptional measures to fight the outbreak of the virus and preserve human lives. These measures have restricted several human rights and fundamental freedoms, in addition to revealing a conflict between the right to protection of health and the right to freedom of movement, both fundamental and essential to the development of the person. However, taken in accordance with the Constitution and with the aim of protecting public health and the life of the population, measures restricting freedom of movement are disproportionate to the health risks. They have given rise to alarming consequences for a poor population deprived of the means of daily survival and social security, and ignore the principle of the indivisibility of human rights.

Breeding biology of the Common Reed Bunting Emberiza schoeniclus: an analysis of Polish nest records

ABSTRACT Citizen-science projects have been remarkably valuable in studying biology of many bird species. Here, I present the analysis of the data on various aspects of breeding biology of the Common Reed Bunting which were collected by volunteer citizen scientists in the Polish Nest Record Scheme. Data from each nest were recorded in form of a card which provided the following parameters: nesting habitat, nesting location, nest structure, nest height, breeding phenology and brood survival. Overall, 420 nest cards collected over the period of 53 years (1969–2022) were analysed. Most nests were found in meadows and pastures. Late April and early May were identified as the peak of the breeding season, with the highest number of initiation dates recorded in nest cards. The most frequent clutch size was five, with a mean of 4.71 eggs. Daily survival rate for nests at the egg stage was 0.95, and at the nestling stage 0.99. The results were consistent with the findings of other authors. In conclusion, nest record schemes provide insight into the breeding biology of many bird species on a scale that would not be achievable in systematic studies.

EFFECT OF BIOACTIVE PROTEIN INGREDIENTS (MOTIVTM) ON TOTAL HEMOCYTE AND SURVIVAL RATE OF VANNAMEI SHRIMP, Litopenaeus vannamei

One of the problematic factors in the cultivation of vannamei shrimp is the outbreak of bacteria and viruses. One way to prevent infection is by strengthening the shrimp’s immune system. MOTIVTM is a fermented corn protein concentrate that has been reported to possess probiotic properties that can positively increase the disease resistance of shrimp. Therefore, this study aimed to determine the effect of bioactive protein (MOTIVTM) on the total hemocyte count and shrimp survival rate. The study used an experimental method with a completely randomized design with five treatments and three replications: A (commercial feed), B (7.5% MOTIV add of 1.5% krill meal instead of 9% fish meal), C (7.5% MOTIVTM add of 1% krill meal to replaces of 2% poultry meal and 6.5% fish meal), D (7.5% MOTIVTM to replaces of 3.5% poultry meal and 4% fish meal), and E (7.5% MOTIVTM to replaces of 7.5% poultry flour). Feeding was done four times/day based on shrimp biomass and weekly feed counts based on daily shrimp survival. The vannamei shrimp used was one gram with a population density of 15 shrimps/aquarium with an aquarium volume of 100 liters.Total shrimp hemocytes, survival, and water quality were all measured. Treatment C had the highest total hemocyte, averaging 4.1 x 107 cells/mL, whereas treatment B had the lowest, averaging 1.4 x 107 cells/mL. During the trial, only treatment C supported 100% survival.

Optimization of Milk Substitutes for the Artificial Rearing of Chinese Tree Shrews (Tupaia belangeri chinensis).

Simple SummaryThe Chinese tree shrew, a squirrel-like mammal, has been widely used as a laboratory animal in biological research. However, the low survival rate of the pups has seriously hindered the establishment of inbred lines of this species and further limited its wider use. We found a milk substitute appropriate for artificial rearing of Chinese tree shrew pups independent of any obvious adverse effects on their survival, health, and reproductive performance compared to those of the maternally reared pups. The successful optimization of a milk substitute for the artificial rearing of Chinese tree shrew pups may increase the availability of this experimental animal.The Chinese tree shrew (Tupaia belangeri chinensis) has the potential to replace the use of non-human primates in biomedical research. To increase the availability of this species, we have undertaken the ambitious task of establishing inbred lines of the Chinese tree shrew; however, we have been hindered by a low survival rate of inbred pups. Here, we report our artificial rearing (AR) of Chinese tree shrew pups using four different milk substitutes: the formula described by Tsang and Collins (milk TC) and three commercially available milk substitutes intended for possums (milk A and milk C) and for guinea pigs (milk B). We compared the effects of these milk substitutes and maternal milk on the daily milk consumption, growth performance, and survival of the pups. We also assessed the life span and reproductive performance of the F1 individuals given the best milk substitute as compared to the maternally reared (MR) pups. Milk B was found to be appropriate for AR. Pups fed with milk B had a high survival rate at the weaning age compared to those fed with the other milk substitutes. The AR pups fed with milk B had a life span similar to that of MR pups. AR females fed with milk B had an earlier age of the first reproduction, a larger number of litters, and a higher rate of survival of the offspring at the weaning age compared with the MR females. The successful optimization of a milk substitute for AR of Chinese tree shrew pups will undoubtedly facilitate the wide usage of this experimental animal.

Nest survival of the Snowy Plover Charadrius nivosus at Marismas Nacionales, Nayarit

Breeding habitat loss and nest predation are considered the main causes of Snowy Plover (Charadrius nivosus) populations decline worldwide. We evaluated the effects of season, nest age, distance to nearest vegetation patch, distance to nearest body of water, habitat type, and nesting substrate on the daily survival rate of Snowy Plover nests. During 2014-2015, we located 84 nests in Las Garzas-Chahuin-Chihua lagoon in Marismas Nacionales, Nayarit, Mexico. We used MARK software to estimate daily nest survival rate, which was 0.969 (95% CI = 0.95 - 0.97) for both breeding seasons combined, with a 42% finite nesting success. A total of 44 nests (52%) were successful, while 40 (48%) failed. The main causes of nest failure were predation (n = 30; 75% of failed nests) and flooding (n = 9; 22.5% of failed nests); one nest was lost due to unknown causes (2.5%). Daily survival rate increased with nest age and distance from the nearest vegetation patch. By contrast, daily survival rate decreased with the progression of the breeding season; a higher probability of nest success was evident when established early in the breeding season. Our results show the importance of different positive and negative factors influencing nest survival that might be considered as part of conservation strategies.

The Effect of Feeding Frequency on Groth and Survival Rate of Keperas Fish (Pentius brevis)

Keperas (Pentius brevis) is a fish that has important economic value and is in great demand among the people of Central Aceh. The population of keperas fish has begun to decrease due to the catch of the surrounding community, so efforts are needed to be cultivated. In cultivation activities, it is necessary to know the proper management of feeding, one of which is the frequency of feeding. The research design used in this study was RAL with 3 treatments and 3 repetitions. The treatments given were different feeding frequency (P1 = 2 times per day, P2 = 3 times per day and P3 = 4 times per day). Parameters observed included absolute length and mutlat weight growth, daily growth rate, feed efficiency and survival rate. Based on ANOVA, feeding frequency had a significant effect (P<0.05) on growth in length and absolute weight and feed efficiency, but had no significant effect (P>0.05) on daily growth rate and survival rate. The best treatment was produced by feeding 3 times per day (P2) because it produced the highest growth performance among other treatments

Malaria mosquitoes acquire and allocate cattle urine to enhance life history traits

BackgroundNutrient acquisition and allocation integrate foraging and life-history traits in insects. To compensate for the lack of a particular nutrient at different life stages, insects may acquire these through supplementary feeding, for example, on vertebrate secretions, in a process known as puddling. The mosquito Anopheles arabiensis emerges undernourished, and as such, requires nutrients for both metabolism and reproduction. The purpose of this study was to assess whether An. arabiensis engage in puddling on cattle urine to obtain nutrients to improve life history traits.MethodsTo determine whether An. arabiensis are attracted to the odour of fresh, 24 h, 72 h and 168 h aged cattle urine, host-seeking and blood-fed (48 h post-blood meal) females were assayed in a Y-tube olfactometer, and gravid females assessed in an oviposition assay. Combined chemical and electrophysiological analyses were subsequently used to identify the bioactive compounds in all four age classes of cattle urine. Synthetic blends of bioactive compounds were evaluated in both Y-tube and field assays. To investigate the cattle urine, and its main nitrogenous compound, urea, as a potential supplementary diet for malaria vectors, feeding parameters and life history traits were measured. The proportion of female mosquitoes and the amount of cattle urine and urea imbibed, were assessed. Following feeding, females were evaluated for survival, tethered flight and reproduction.ResultsHost-seeking and blood-fed An. arabiensis were attracted to the natural and synthetic odour of fresh and aged cattle urine in both laboratory and field studies. Gravid females were indifferent in their response to cattle urine presence at oviposition sites. Host-seeking and blood-fed females actively imbibed cattle urine and urea, and allocated these resources according to life history trade-offs to flight, survival or reproduction, as a function of physiological state.ConclusionsAnopheles arabiensis acquire and allocate cattle urine to improve life history traits. Supplementary feeding on cattle urine affects vectorial capacity directly by increasing daily survival and vector density, as well as indirectly by altering flight activity, and thus should be considered in future models.

Density-dependence of reproductive success in a Houbara bustard population

Although density-dependent processes and their impacts on population dynamics are key issues in ecology and conservation biology, empirical evidence of density-dependence remains scarce for species or populations with low densities, scattered distributions, and especially for managed populations where densities may vary as a result of extrinsic factors (such as harvesting or releases). Here, we explore the presence of density-dependent processes in a reinforced population of North African Houbara bustard ( Chlamydotis undulata undulata ). We investigated the relationship between reproductive success and local density, and the possible variation of this relationship according to habitat suitability using three independent datasets. Based on eight years of nests monitoring (more than 7000 nests), we modeled the Daily Nest Survival Rate (DNSR) as a proxy of reproductive success. Our results indicate that DNSR was negatively impacted by local densities and that this relationship was approximately constant in space and time: (1) although DNSR strongly decreased over the breeding season, the negative relationship between DNSR and density remained constant over the breeding season; (2) this density-dependent relationship did not vary with the quality of the habitat associated with the nest location. Previous studies have shown that the demographic parameters and population dynamics of the reinforced North African Houbara bustard are strongly influenced by extrinsic environmental and management parameters. Our study further indicates the existence of density-dependent regulation in a low-density, managed population. • Density-dependency mechanisms also occur in low-density populations. • Reproductive performance is impacted by the density of birds around the nests. • Density-dependent effects do not vary in space and time.

Temporal variation and landcover influence survival in adult female mottled ducks

AbstractAdult survival is a key driver of waterfowl population growth and is subject to temporal and spatial variation. Mottled ducks (Anas fulvigula) are native to the Gulf Coast and peninsular Florida, USA, and have suffered population declines over the past decade, especially in Texas and Louisiana, USA. Although the cause of this decline is not well understood, previous research concluded variation in survival contributed to nearly a third of variation in the species' population growth rate. We used global positioning system‐groupe spécial mobile (GPS‐GSM) transmitters to study temporal and spatial variation in survival of adult female western Gulf Coast mottled ducks in southwestern Louisiana, 2017–2020. We evaluated weekly survival models parameterized with combinations of hunted and non‐hunted periods, biological seasons, and landcover types that were used by mottled ducks. There were 3 competitive survival models, and all contained 4 parameters that parsed the annual cycle into the non‐hunted period, first part of the general waterfowl season, and second part of the waterfowl season, and included the proportion of GPS locations in agricultural lands. Weekly survival was 0.979 during the first part of the general waterfowl hunting season, and 0.996 during the second part of the general waterfowl season. Daily survival rate increased with an increasing proportion of locations logged in agricultural lands. Annual survival rates were similar to other waterfowl that are not experiencing population declines, which suggests survival is not limiting population growth of mottled ducks along the western Gulf Coast. Managers should ensure the availability of refuge areas where hunting is prohibited during the first part of the general waterfowl season, when mottled ducks are at an increased risk of mortality, in addition to the targeted conservation of agricultural lands that provide cover and forage.

Breeding season survival of female Rio Grande wild turkeys in south‐central Texas

AbstractHistorically, Rio Grande wild turkey (Meleagris gallopavo intermedia) density in south‐central Texas has been lower than other regions within the species' Texas range. Within the Oak‐Prairie Wildlife District of Texas, Rio Grande wild turkey harvest regulations are more restrictive for counties in the eastern portion of the district. Due to a perceived increase in turkey density in the eastern portion of the district, Texas Parks and Wildlife Department (TPWD) has considered increasing the spring hunting season harvest bag limit. Because estimates of sex‐specific abundance and male harvest rates are not available, estimates of female driven population parameters such and nest success and female survival can be used to support regulatory decision‐making. Therefore, before a regulation change we evaluated survival of radio‐marked female Rio Grande wild turkeys during the breeding season in 4 counties in the Special 1‐Male zone (hereafter 1‐bird zone) and 2 counties in the South zone (hereafter 4‐bird zone). We captured and monitored breeding season survival for 138 females during 2016–2018, of which 51 were in the 4‐bird zone and 87 were in the 1‐bird zone. Breeding season (1 Mar–14 Aug) naive mortality rate was 23% (19/81) of tagged females in the 1‐bird zone and 32% (14/43) in the 4‐bird zone. The best approximating candidate model for breeding season survival indicated variation in daily survival () was primarily related to daily distance of individual movements ( = 0.998 at average daily distance of 2,471 m). Estimated breeding season survival at the mean daily movement distance was 81% for the 167‐day period. Breeding season survival was similar between the 1‐bird and 4‐bird regulatory zone. Based on our results, female breeding season survival does not seem to be a limiting factor within the Oak‐Prairie Wildlife District of Texas for Rio Grande wild turkeys. We suggest that TPWD focus efforts on supporting landowners to enhance conditions more conducive for reproductive success and suggest future efforts focus on collection of harvest and harvest rate data to estimate population size in lieu of continued monitoring of female reproductive or survival parameters for decision processes.