Modelling survival and breeding dispersal to unobservable nest sites

Context Demographic parameters in wildlife populations are typically estimated by monitoring a limited number of individuals in observable sites and assuming that these are representative of the whole population. If individuals permanently disperse to unobservable breeding sites, recruitment and immature survival are expected to be negatively biased and breeding-site fidelity cannot be investigated. Aims To develop a method to obtain unbiased estimated of survival, recruitment and breeding dispersal when individuals can move to, or recruit in, unobservable sites. Methods We used the flexibility of multi-event capture–recapture models to estimate dispersal and recruitment to unobservable sites, merging observations made at two sites within the same breeding locations. We illustrated the model with data on little penguin (Eudyptula minor) breeding in artificial as well as in natural nests. Natural nests are unknown or inaccessible and birds in these sites remain unobservable. Encounters at beaches surrounding the colony suggested that marked animals can permanently move to unobservable nests. We built the multi-event model considering two possible states of the individuals (alive breeding in a nest box and alive in a natural nest) and three types of observations (encountered at a nest only, encountered at the beach only and encountered at both places). This model ensured that the breeding dispersal to unobservable places became estimable. Key results Results indicate that the estimated survival was 8% higher than when recaptures at artificial nests were analysed alone. Also, fidelity to artificial nests was 12% lower than to natural nests. This might reflect the greater availability of natural sites or, alternatively, a heterogeneity between these two types of nest. Conclusions We obtained an estimate of local survival of little penguins breeding at Penguin Island that incorporates the permanent migration to unobservable sites and found an asymmetric dispersion towards natural nests. Implication Our conclusions suggest a need for more careful treatment of data derived from artificial sites alone, as demographic parameters might be underestimated if animals prefer natural breeding sites or if they are in greater proportion compared with artificial ones. The analytical approach presented can be applied to many biological systems, when animals might move into inaccessible or unobservable breeding sites.

Download Full-text

Breeding behaviour and reproduction in the Pampa de Achala toad, Bufo achalensis

Amphibia-Reptilia ◽

10.1163/156853805774806124 ◽

2005 ◽

Vol 26 (4) ◽

pp. 451-458 ◽

Cited By ~ 5

Author(s):

◽

Keyword(s):

Breeding Site ◽

Reproductive Behaviour ◽

Breeding Population ◽

Male Reproductive Success ◽

Breeding Sites ◽

Size Dependent ◽

Breeding Populations ◽

Site Characteristics ◽

Capture Recapture ◽

First Time

AbstractDuring 1999 and 2000 the reproductive behaviour, breeding site characteristics and reproduction of Bufo achalensis were studied mainly at La Ciénaga stream, Pampa de Achala, Argentina, using capture-recapture and skeletochronology methods. Breeding activity occurred from mid-August to mid-September and was explosive. Males and females congregated at night at selected, but scarce, breeding sites, resulting in a patchy distribution of small breeding populations near to the stream source. The sex ratio (♂ : ♀) of the breeding population ranged between 0.65 : 1 and 1.16 : 1. On average, breeding males were larger and older than breeding females. Although most females and males reached sexual maturity at four and five years of age, some bred for the first time at the ages of three and four years respectively. Neither size dependent nor size assortative pairings were found. Male reproductive success was not related to body size (SVL) but was related to the number of nights spent at a breeding site. Females laid between 700-2,390 eggs. Eggs hatched approximately nine days after deposition and larval development was completed in about two months.

Download Full-text

Comparing the effects of release methods on survival of the Eurasian black vulture Aegypius monachus reintroduced in France

Oryx ◽

10.1017/s0030605312000981 ◽

2013 ◽

Vol 48 (1) ◽

pp. 106-115 ◽

Cited By ~ 11

Author(s):

Jean-Baptiste Mihoub ◽

Karine Princé ◽

Olivier Duriez ◽

Philippe Lécuyer ◽

Bertrand Eliotout ◽

...

Keyword(s):

Survival Rates ◽

Population Viability ◽

Artificial Nests ◽

Viability Analysis ◽

Tag Loss ◽

Black Vulture ◽

In The Wild ◽

Capture Recapture ◽

Similar Survival ◽

Event Capture

AbstractThe Near Threatened Eurasian black vulture Aegypius monachus is considered highly threatened in Europe, and the species was reintroduced in France between 1992 and 2004. A total of 53 individuals were released, using two methods: immatures were released from large aviaries at the reintroduction site after a stay of several months (the aviary method), whereas juveniles were placed on artificial nests until fledging (the hacking method). The survival rates of released birds were compared to the survival of wild-born offspring through a multi-event capture–recapture analysis accounting for tag loss. Survival rates were higher in adults than in juveniles and immatures (0.98 ± SE 0.02 vs 0.85 ± SE 0.03) and were constant over time. Overall there were no differences in post-release survival between the two release methods: immatures released by the aviary method had a similar survival to juveniles released by the hacking method or born in the wild. Immatures can breed before juveniles, so releasing immatures by the aviary method could accelerate reintroduction settlement and increase population viability. Accurate estimates of post-release survival are essential to improve the reliability of viability analysis of reintroduced populations and the management of such populations.

Download Full-text

Age and Sex Influence Natal and Breeding Dispersal of Purple Martins

Western Birds ◽

10.21199/wb54.4.2 ◽

2021 ◽

Vol 52 (4) ◽

pp. 296-310

Author(s):

Carolyn A. Cook ◽

Glen T. Hvenegaard ◽

Geoffrey L. Holroyd ◽

Hardy Pletz ◽

Myrna Pearman

Keyword(s):

Environmental Changes ◽

Average Distance ◽

Breeding Site ◽

Breeding Dispersal ◽

Dispersal Patterns ◽

Nest Sites ◽

Migration Dynamics ◽

Second Year ◽

Dispersal Distances ◽

Age And Sex

Dispersal patterns deepen our understanding of population dynamics. Dispersal by all age and sex classes enhances a species’ ability to respond to environmental changes, such as in habitat availability, artificial nest sites, and climate. The migration dynamics of the eastern subspecies of the Purple Martin (Progne subis subis) are well known, but we know less about its patterns of annual dispersal. We compared the frequency, distance, and direction of dispersal by each age/sex cohort of martins in central Alberta, at the northwestern limit of their breeding range. We used two datasets: (1) adult martins banded in central Alberta as nestlings and encountered during the summers of 2017 and 2018, and (2) records of encounters of banded martins in Canada from 1935 to 2016 from the Canadian Wildlife Service’s Bird Banding Office. In Alberta, 36% of birds dispersed from natal sites (by an average distance of 24 km), most commonly to the northeast. Across Canada, 29% of birds dispersed (by an average distance of 183 km), most commonly to the east and northeast. In Alberta, martins at least two years old dispersed less frequently than yearlings since some older martins returned to their natal site after first breeding elsewhere. Dispersal distances of after-second-year martins, which represent natal plus breeding dispersal, were greater than those of second-year birds, which represent natal dispersal alone. Thus some martins continue to disperse after their second year and do not maintain complete fidelity to a breeding site, which is different from our current understanding.

Download Full-text

Comparação de testes coproparasitológicos em criadouro comercial de psitacídeos exóticos

Revista Agraria Academica ◽

10.32406/v3n52020/100-107/agrariacad ◽

2020 ◽

Vol 3 (5) ◽

pp. 100-107

Author(s):

Marina Camargo de Sousa ◽

◽

Julia Ronzani Vial ◽

Rodrigo Hidalgo Friciello Teixeira ◽

Andrea Cristina Higa Nakaghi ◽

...

Keyword(s):

Statistical Tests ◽

Companion Animals ◽

Clinical Importance ◽

Breeding Site ◽

Chi Square ◽

Fecal Samples ◽

Breeding Sites ◽

Specificity And Sensitivity ◽

Nematode Eggs ◽

Commercial Breeding

Birds of the psittaciform order, composed by the Psittacidae and Loridae family have several characteristics making them more frequently kept as companion animals, promoting the increase of breeding sites in Brazil. The present study aimed to analyze the specificity and sensitivity of three different coproparasitological tests, Willis, Hoffman and Direto de feces, through statistical tests: Chi-Square and Kappa. 70 fecal samples of exotic parrots were collected from a commercial breeding site and these were submitted to the three tests, totaling 210 coproparasitological exams. Among the tests performed, 29,5% were positive for nematode eggs, cestodes and oocysts. Coproparasitological exams are inexpensive, have clinical importance, indicating the population of endoparasites and therapeutic treatments.

Download Full-text

Non-Invasive Molecular Survey of Sarcoptic Mange in Wildlife: Diagnostic Performance in Wolf Faecal Samples Evaluated by Multi-Event Capture–Recapture Models

Pathogens ◽

10.3390/pathogens10020243 ◽

2021 ◽

Vol 10 (2) ◽

pp. 243

Author(s):

Julieta Rousseau ◽

Mónia Nakamura ◽

Helena Rio-Maior ◽

Francisco Álvares ◽

Rémi Choquet ◽

...

Keyword(s):

Molecular Detection ◽

High Specificity ◽

Sarcoptes Scabiei ◽

Sarcoptic Mange ◽

Diagnostic Specificity ◽

Non Invasive ◽

Faecal Samples ◽

Capture Recapture ◽

The Mean ◽

Event Capture

Sarcoptic mange is globally enzootic, and non-invasive methods with high diagnostic specificity for its surveillance in wildlife are lacking. We describe the molecular detection of Sarcoptes scabiei in non-invasively collected faecal samples, targeting the 16S rDNA gene. We applied this method to 843 Iberian wolf Canis lupus signatus faecal samples collected in north-western Portugal (2006–2018). We further integrated this with serological data (61 samples from wolf and 20 from red fox Vulpes vulpes, 1997–2019) in multi-event capture–recapture models. The mean predicted prevalence by the molecular analysis of wolf faecal samples from 2006–2018 was 7.2% (CI95 5.0–9.4%; range: 2.6–11.7%), highest in 2009. The mean predicted seroprevalence in wolves was 24.5% (CI95 18.5–30.6%; range: 13.0–55.0%), peaking in 2006–2009. Multi-event capture–recapture models estimated 100% diagnostic specificity and moderate diagnostic sensitivity (30.0%, CI95 14.0–53.0%) for the molecular method. Mange-infected individually identified wolves showed a tendency for higher mortality versus uninfected wolves (ΔMortality 0.150, CI95 −0.165–0.458). Long-term serology data highlights the endemicity of sarcoptic mange in wild canids but uncovers multi-year epidemics. This study developed and evaluated a novel method for surveying sarcoptic mange in wildlife populations by the molecular detection of S. scabiei in faecal samples, which stands out for its high specificity and non-invasive character.

Download Full-text

Recruitment, Dispersal, and Demographic Rescue in Spatially-Structured White-Tailed Ptarmigan Populations

The Condor ◽

10.1093/condor/102.3.503 ◽

2000 ◽

Vol 102 (3) ◽

pp. 503-516 ◽

Cited By ~ 8

Author(s):

Kathy Martin ◽

Peter B. Stacey ◽

Clait E. Braun

Keyword(s):

General Pattern ◽

Population Connectivity ◽

Site Location ◽

Breeding Sites ◽

Stochastic Conditions ◽

Local Survival ◽

Regular Event ◽

Study Sites ◽

One Year ◽

Almost All

Abstract We studied recruitment and dispersal of White-tailed Ptarmigan (Lagopus leucurus) breeding in naturally fragmented alpine habitats at four study sites in Colorado from 1987–1998. Almost all recruitment for both sexes, particularly females, was of birds produced outside local populations and also external to nearby studied populations. Populations were more dependent on female recruitment than on male recruitment to sustain them, and patterns of recruitment were not correlated with local survival of adults or production of young the previous year, except at one site for females. Over 95% of recruits were yearlings. Breeding dispersal of adults, an infrequent but regular event, was also important to inter-population connectivity. Our data for multiple populations allowed us to describe movement patterns among populations to assess consistency with conditions required for a rescue system. After widespread reproductive failure in one year, we expected all populations the next year would have low recruitment due to a reduced supply of recruits produced in the region. Recruitment was low, but impact varied among populations. We conducted an over-winter study of radio-marked offspring to determine possible influences of winter site location and relatives on recruitment patterns. Contrary to expectation, offspring remained on or near breeding sites in winter, but were not located near their mothers or siblings. Recruitment location was related to winter site location. White-tailed Ptarmigan exhibit a well developed capacity for external recruitment that allows them to persist in small populations with stochastic conditions for breeding and survival. Extensive external recruitment may be a general pattern for birds.

Download Full-text

Biological and environmental factors associated with risk of schistosomiasis mansoni transmission in Porto de Galinhas, Pernambuco State, Brazil

Cadernos de Saúde Pública ◽

10.1590/s0102-311x2013000200022 ◽

2013 ◽

Vol 29 (2) ◽

pp. 357-367 ◽

Cited By ~ 5

Author(s):

Onicio Batista Leal Neto ◽

Elainne Christine de Souza Gomes ◽

Fernando José Moreira de Oliveira Junior ◽

Rafael Andrade ◽

Diego Leandro Reis ◽

...

Keyword(s):

Environmental Factors ◽

Infection Rate ◽

Breeding Site ◽

Transmission Risk ◽

Host Snail ◽

Breeding Sites ◽

Positive Correlation ◽

Snail Density ◽

One Year ◽

Transmission Foci

Schistosomiasis has expanded to the coast of Pernambuco State, Brazil, where there are frequent reports of Biomphalaria glabrata snails and human cases of the disease. This study analyzes factors related to schistosomiasis transmission risk in Porto de Galinhas. A one-year malacological survey was conducted to identify biological, abiotic, and environmental factors related to the host snail breeding sites. Data analysis used Excel 2010, GTM Pro, and ArcGis 10. A total of 11,012 B. glabrata snails were captured in 36 breeding sites, and 11 schistosomiasis transmission foci were identified. A negative correlation was found between breeding site temperature and snail density and infection rate, and a positive correlation with pH and salinity. The rainy season showed a positive correlation with snail density and infection rate. The study emphasizes the factors involved in the maintenance of schistosomiasis breeding sites, in light of persistence of this disease in Porto de Galinhas for more than 10 years.

Download Full-text

Comparação de testes coproparasitológicos em criadouro comercial de psitacídeos exóticos

Revista Agraria Academica ◽

10.32406/v3n5/2020/100-107/agrariacad ◽

2020 ◽

Vol 3 (5) ◽

pp. 100-107

Author(s):

Marina Camargo de Sousa ◽

◽

Julia Ronzani Vial ◽

Rodrigo Hidalgo Friciello Teixeira ◽

Andrea Cristina Higa Nakaghi ◽

...

Keyword(s):

Statistical Tests ◽

Companion Animals ◽

Clinical Importance ◽

Breeding Site ◽

Chi Square ◽

Fecal Samples ◽

Breeding Sites ◽

Specificity And Sensitivity ◽

Nematode Eggs ◽

Commercial Breeding

Download Full-text

Breeding site selection by coho salmon (Oncorhynchus kisutch) in relation to large wood additions and factors that influence reproductive success

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2014-0020 ◽

2014 ◽

Vol 71 (10) ◽

pp. 1498-1507 ◽

Cited By ~ 3

Author(s):

Steven M. Clark ◽

Jason B. Dunham ◽

Jeffrey R. McEnroe ◽

Scott W. Lightcap

Keyword(s):

Site Selection ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Breeding Site ◽

Large Wood ◽

Fitness Components ◽

Breeding Sites ◽

Habitat Features ◽

Egg Incubation ◽

Wide Range

The fitness of female Pacific salmon (Oncorhynchus spp.) with respect to breeding behavior can be partitioned into at least four fitness components: survival to reproduction, competition for breeding sites, success of egg incubation, and suitability of the local environment near breeding sites for early rearing of juveniles. We evaluated the relative influences of habitat features linked to these fitness components with respect to selection of breeding sites by coho salmon (Oncorhynchus kisutch). We also evaluated associations between breeding site selection and additions of large wood, as the latter were introduced into the study system as a means of restoring habitat conditions to benefit coho salmon. We used a model selection approach to organize specific habitat features into groupings reflecting fitness components and influences of large wood. Results of this work suggest that female coho salmon likely select breeding sites based on a wide range of habitat features linked to all four hypothesized fitness components. More specifically, model parameter estimates indicated that breeding site selection was most strongly influenced by proximity to pool-tail crests and deeper water (mean and maximum depths). Linkages between large wood and breeding site selection were less clear. Overall, our findings suggest that breeding site selection by coho salmon is influenced by a suite of fitness components in addition to the egg incubation environment, which has been the emphasis of much work in the past.

Download Full-text

Breeding transients in capture–recapture modeling and their consequences for local population dynamics

Scientific Reports ◽

10.1038/s41598-020-72778-x ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Daniel Oro ◽

Daniel F. Doak

Keyword(s):

Growth Rate ◽

Population Dynamics ◽

Population Growth ◽

Population Growth Rate ◽

Local Population ◽

Environmental Stochasticity ◽

Adult Survival ◽

Local Survival ◽

First Reproduction ◽

Capture Recapture

Abstract Standard procedures for capture–mark–recapture modelling (CMR) for the study of animal demography include running goodness-of-fit tests on a general starting model. A frequent reason for poor model fit is heterogeneity in local survival among individuals captured for the first time and those already captured or seen on previous occasions. This deviation is technically termed a transience effect. In specific cases, simple, uni-state CMR modeling showing transients may allow researchers to assess the role of these transients on population dynamics. Transient individuals nearly always have a lower local survival probability, which may appear for a number of reasons. In most cases, transients arise due to permanent dispersal, higher mortality, or a combination of both. In the case of higher mortality, transients may be symptomatic of a cost of first reproduction. A few studies working at large spatial scales actually show that transients more often correspond to survival costs of first reproduction rather than to permanent dispersal, bolstering the interpretation of transience as a measure of costs of reproduction, since initial detections are often associated with first breeding attempts. Regardless of their cause, the loss of transients from a local population should lower population growth rate. We review almost 1000 papers using CMR modeling and find that almost 40% of studies fitting the searching criteria (N = 115) detected transients. Nevertheless, few researchers have considered the ecological or evolutionary meaning of the transient phenomenon. Only three studies from the reviewed papers considered transients to be a cost of first reproduction. We also analyze a long-term individual monitoring dataset (1988–2012) on a long-lived bird to quantify transients, and we use a life table response experiment (LTRE) to measure the consequences of transients at a population level. As expected, population growth rate decreased when the environment became harsher while the proportion of transients increased. LTRE analysis showed that population growth can be substantially affected by changes in traits that are variable under environmental stochasticity and deterministic perturbations, such as recruitment, fecundity of experienced individuals, and transient probabilities. This occurred even though sensitivities and elasticities of these parameters were much lower than those for adult survival. The proportion of transients also increased with the strength of density-dependence. These results have implications for ecological and evolutionary studies and may stimulate other researchers to explore the ecological processes behind the occurrence of transients in capture–recapture studies. In population models, the inclusion of a specific state for transients may help to make more reliable predictions for endangered and harvested species.

Download Full-text