scholarly journals A new approach to the “apparent survival” problem: estimating true survival rates from mark–recapture studies

Ecology ◽  
2012 ◽  
Vol 93 (7) ◽  
pp. 1509-1516 ◽  
Author(s):  
James J. Gilroy ◽  
Thomas Virzi ◽  
Rebecca L. Boulton ◽  
Julie L. Lockwood
Keyword(s):  
Survival Rates ◽  
Apparent Survival ◽  
Mark Recapture ◽  
New Approach

scholarly journals Age-specific survival in an English Twite population.

2021 ◽  
Author(s):  
Ismini Gkourtsouli-Antoniadou ◽  
Steven R. Ewing ◽  
George Hudson ◽  
Michael A. Pearson ◽  
Julia Schroeder ◽  
...  
Keyword(s):  
Habitat Degradation ◽  
Survival Rates ◽  
Bird Species ◽  
Small Population ◽  
Juvenile Survival ◽  
Apparent Survival ◽  
Mark Recapture ◽  
The Uk ◽  
Rule Out

Like many bird species associated with agricultural habitats in the UK, the Twite Linaria flavirostris has undergone severe declines over recent decades due to habitat degradation, with populations in England, Wales and Ireland now restricted to a few small pockets. However, the demographic drivers of these declines are still largely unresolved. We estimated the survival of Twite from a small population at the southernmost edge of the English range in Derbyshire using capture-mark-recapture data from 2016–2019. Annual apparent survival for juveniles (0.14–0.34) was lower than for adults (0.29–0.56) and less than that of other Cardueline finches. Our results suggest that low juvenile survival may be one demographic driver underpinning the recent decline of the Derbyshire Twite population, although we also cannot rule out the possibility that differences in emigration of juveniles and adults from the population also contribute to the observed age-specific apparent survival rates.

Closure violation in DNA-based mark-recapture estimation of grizzly bear populations

2001 ◽  
Vol 79 (4) ◽  
pp. 642-651 ◽  
Author(s):  
John Boulanger ◽  
Bruce McLellan
Keyword(s):  
Population Model ◽  
Ursus Arctos ◽  
Survival Rates ◽  
Grizzly Bear ◽  
Apparent Survival ◽  
Mark Recapture ◽  
Closed Model ◽  
Closed Population ◽  
The Relationship ◽  
Grid Based

We use methods in the program MARK to explore the effects of closure violation when DNA-based mark–recapture methods are used to estimate grizzly bear (Ursus arctos) populations. Our approach involves the use of Pradel models in MARK to explore the relationship between recruitment, apparent survival rates, recapture rates, and distance between mean bear-capture locations and the edge of the sampling grid. If the population is demographically closed, it can be assumed that apparent survival estimates the fidelity of bears to the grid area and recruitment estimates rates of addition of bears to the grid area. A core bear population is defined from the Pradel analysis and is used to approximate the grid-based population size. The Huggins closed-population model in MARK is used to provide robust superpopulation estimates by explicitly modeling the relationship between capture probability and distance of bear-capture location from the grid edge. Data from a grizzly bear DNA-based mark–recapture inventory conducted in British Columbia is used to illustrate this method. The results of the Pradel analysis suggest that bears with mean capture locations within 10 km of the grid edge exhibit reduced fidelity rates and higher addition rates. Using the population of bears captured more than 10 km from the grid edge, a core-extrapolated estimate is derived, which is substantially lower than naïve CAPTURE superpopulation estimates. The Huggins model superpopulation estimate displays superior precision compared with CAPTURE model estimates. Our results illustrate the danger of naïve interpretation of closed-model estimates. This method allows further inferences to be made concerning the spatial causes of closure violation, and the degree of bias caused by closure violation to be explored.

scholarly journals Apparent Survival Rates of Western Sandpiper (Calidris Mauri) Wintering in Northwest Baja California, Mexico

The Auk ◽  
2003 ◽  
Vol 120 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Guillermo Fernández ◽  
Horacio de la Cueva ◽  
Nils Warnock ◽  
David B. Lank
Keyword(s):  
Hierarchical Modeling ◽  
Survival Rates ◽  
Average Quality ◽  
Apparent Survival ◽  
Calidris Mauri ◽  
Local Survival ◽  
Western Sandpiper ◽  
Western Sandpipers ◽  
Best Fit ◽  
Effect Of Age

AbstractTo estimate annual apparent local survival, we collected capture–resighting data on 256 individually marked male Western Sandpipers (Calidris mauri) wintering at Estero de Punta Banda, Mexico, between 1994–1997. A hierarchical modeling approach was used to address the effect of age class and year on survivorship rates. The best-fit model included a constant apparent survival probability (ϕ = 0.489; 95% CI = 0.410–0.569), but several models fit nearly as well, and averaging among the top five, to account for model uncertainty, suggested that adults had somewhat higher values than juveniles (ϕ = 0.490 ± 0.051 vs. 0.450 ± 0.067). Detection probability was substantially higher for adults than for juveniles (p = 0.741 vs. p = 0.537). Those apparent survival estimates are low compared with those from other studies of Western Sandpipers at breeding and other nonbreeding locations, and substantially lower than the true survivorship rates expected for small sandpipers in general. We interpret these results as indicating that this site is of below average quality for nonbreeding male Western Sandpipers.

scholarly journals Survival rates of adult and juvenile gyrfalcons in Iceland: estimates and drivers

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12404
Author(s):  
Frédéric Barraquand ◽  
Ólafur K. Nielsen
Keyword(s):  
Prey Density ◽  
Survival Rates ◽  
Environmental Drivers ◽  
Juvenile Survival ◽  
Recovery Model ◽  
Mark Recapture ◽  
Weather Effects ◽  
Main Prey ◽  
Positive Effects ◽  
Model Combining

Knowledge of survival rates and their potential covariation with environmental drivers, for both adults and juveniles, is paramount to forecast the population dynamics of long-lived animals. Long-lived bird and mammal populations are indeed very sensitive to change in survival rates, especially that of adults. Here we report the first survival estimates for the Icelandic gyrfalcon (Falco rusticolus) obtained by capture-mark-recapture methods. We use a mark-recapture-recovery model combining live and dead encounters into a unified analysis, in a Bayesian framework. Annual survival was estimated at 0.83 for adults and 0.40 for juveniles. Positive effects of main prey density on juvenile survival (5% increase in survival from min to max density) were possible though not likely. Weather effects on juvenile survival were even less likely. The variability in observed lifespan suggests that adult birds could suffer from human-induced alteration of survival rates.

Estimating the survival rates of Soay sheep from mark—recapture—recovery data

2017 ◽  
pp. 317-329
Author(s):  
Walter Zucchini ◽  
Iain L. MacDonald ◽  
Roland Langrock
Keyword(s):  
Survival Rates ◽  
Mark Recapture ◽  
Soay Sheep

scholarly journals Long-Term Study of Apparent Survival in Pacific Golden-Plovers at a Wintering Ground on Oahu, Hawaiian Islands

The Auk ◽  
2001 ◽  
Vol 118 (2) ◽  
pp. 342-351 ◽  
Author(s):  
Oscar W. Johnson ◽  
Phillip L. Bruner ◽  
Jay J. Rotella ◽  
Patricia M. Johnson ◽  
Andrea E. Bruner
Keyword(s):  
Survival Rates ◽  
Winter Mortality ◽  
Apparent Survival ◽  
Open Population ◽  
Long Term Study ◽  
Minimum Age ◽  
Parsimonious Model ◽  
Territorial Status ◽  
Breeding Seasons ◽  
Wintering Ground

Abstract We monitored the apparent survival of territorial and nonterritorial Pacific Golden-Plovers (Pluvialis fulva) for 20 consecutive nonbreeding seasons at a wintering ground within Bellows Air Force Station (BAFS) on the eastern shore of Oahu, Hawaii. Territorial birds were especially site-faithful from season to season, and each surviving individual reoccupied the same territory held in previous seasons. On average, territorial birds were resighted for about twice as many postbanding seasons (4.2) as nonterritorial birds (1.8). Open-population modeling indicated that apparent survival varied by age and territorial status. Our most parsimonious model estimated apparent annual survival rates in territorial plovers as 0.90 for young birds (age determined from retained juvenal primaries) from their first through their second wintering season, and 0.80 for adults over numerous seasons. For nonterritorial plovers, the corresponding values were 0.82 and 0.67, respectively. Despite lower apparent survival in nonterritorial plovers, it remains uncertain whether nonterritoriality actually results in shorter life spans. Some surviving nonterritorial birds may have gone undetected (detection probability of 0.70) because of permanent emigration from the study area. Given strong site-fidelity of territorial birds and the relative certainty of detecting them (probability = 1.0), we regarded the disappearance of a plover from its territory as an indicator of mortality. From last-recorded sightings, we concluded that territorial birds died with about equal frequency during the nonbreeding and breeding seasons. Because the latter is of much shorter duration, time-relative hazards were greatest while birds were away from the wintering grounds. Winter mortality was caused by accidents (collisions with overhead wires and other obstructions), and probable predation by owls. We estimated mean additional life expectancy among territorial plovers at 5.1 years for first-year birds, and 4.5 years for unknown-age adults. The oldest known-age individual was a male that lived 13 years 10 months; in adults of uncertain ages, one male survived to a minimum age of 18 years 10 months, and two females to at least 17 years 10 months. Pacific Golden-Plovers wintering at BAFS, especially territorial birds, demonstrated relatively high rates of apparent survival combined with adaptability for coexistence with humans in an urban environment.

Estimates of the size of winter flocks of the Pied Currawong, Strepera graculina (Shaw) from mark -recapture data - a new approach

1968 ◽  
Vol 16 (1) ◽  
pp. 27 ◽  
Author(s):  
JL Readshaw
Keyword(s):  
Population Size ◽  
Emigration And Immigration ◽  
New Method ◽  
Random Numbers ◽  
Sampling Effort ◽  
Mark Recapture ◽  
New Approach ◽  
The Common ◽  
Winter Flocks ◽  
Common Situation

Banding records were used to estimate the size of non-breeding winter flocks of the pied currawong, Strepera graculina, at Albury, N.S.W., during 1964 and 1965. A new method of analysing mark-recapture data is compared with conventional methods, and it is shown that the flocks contained between 500 and 1000 birds in both years. In 1964, the new method provided information on emigration and immigration that was not apparent when the data were treated in the conventional way. The new approach considers the common situation in which a population (flock) is sampled continuously by catching one member (bird) at a time, marking (banding) it, and returning it to the population. For closed populations, the population size was estimated by a method involving cumulative catch and recapture data. Subsequently, this method was successfully tested by simulating the sampling of 20 "populations" of 10,000 random numbers with a computer. The method also provided a simple way of controlling sampling effort based on recapture data to obtain any desired precision in the estimation of population size.

Juvenile survival and recruitment in a population of Weddell seals (Leptonychotes weddellii) in McMurdo Sound, Antarctica

1987 ◽  
Vol 65 (12) ◽  
pp. 2993-2997 ◽  
Author(s):  
J. Ward Testa
Keyword(s):  
Census Data ◽  
Survival Rates ◽  
Breeding Population ◽  
Weddell Seal ◽  
Adult Survival ◽  
Juvenile Survival ◽  
Apparent Survival ◽  
Mcmurdo Sound ◽  
Juvenile Dispersal ◽  
Weddell Seals

Survival and recruitment of Weddell seal pups were studied in eastern McMurdo Sound, Antarctica. Pups were marked and their apparent survival estimated by mark–recapture methods. The resulting estimates were used together with published estimates of adult survival, yearly sighting probabilities, and direct counts of pup production to simulate the dynamics of the population and evaluate the assumption that it is closed to immigration. Estimates derived from census data in 1982 and 1983 were over five times larger than those simulated. This discrepancy was due to the extremely low juvenile survival rates calculated from marked seals. Since few animals born in Erebus Bay return to breed, the large adult breeding population must be the result of substantial immigration, indicating an important role for juvenile dispersal in the population dynamics of Weddell seals.

scholarly journals Mark-recapture estimates of daily survival rates of two damselflies (Coenagrion puella and Ischnura elegans)

2001 ◽  
Vol 79 (5) ◽  
pp. 895-899 ◽  
Author(s):  
Bradley R. Anholt ◽  
Christoph Vorburger ◽  
Peter Knaus
Keyword(s):  
Survival Rates ◽  
Mark Recapture ◽  
Ischnura Elegans ◽  
Daily Survival
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