Survival probabilities and movements of harbor seals in central California

Harbor seal numbers and population trajectories differ by location in central California. Within San Francisco Bay (SFB) counts have been relatively stable since the 1972 Marine Mammal Protection Act, but in coastal areas like Tomales Bay (TB), counts increased before stabilizing in the 1990s. Emigration, poor survival, and environmental effects have been hypothesized as contributors to differences between trajectories; however, basic demographic data were not available to evaluate these hypotheses. We monitored 32 radio‐tagged adult females (SFB n = 17, TB n = 15) for 20 mo (2011–2013), and estimated survival, resight, and movement probabilities using mark‐resight analyses and multistate mark‐resight models. Annual survival probability for both sites was 0.90 (95% CI = 0.18–0.99). Six seals were observed moving between locations resulting in an estimated probability of 0.042 (95% CI = 0.023–0.076) per month equal movement between sites. Resight probability was less in SFB relative to TB, likely due to differential haul‐out access, area surveyed, visibility, and resight effort. Because of wide confidence intervals and low precision of these first estimates of adult female harbor seal survival in California, this demographic must be further examined to dismiss its contribution to differing population trajectories. Using aerial survey data, we estimated 950 harbor seals in SFB (95% CI = 715–1,184) confirming numbers are still stable.     

An Integrated Population Model for Harvest Management of Atlantic Brant

Atlantic brant (Branta bernicla hrota) are important game birds in the Atlantic Flyway and several long-term monitoring data sets could assist with harvest management, including a count-based survey and demographic data. Considering their relative strengths and weaknesses, integrated analysis to these data would likely improve harvest management, but tools for integration have not yet been developed. Managers currently use an aerial count survey on the wintering grounds, the mid-winter survey, to set harvest regulations. We developed an integrated population model (IPM) for Atlantic brant that uses multiple data sources to simultaneously estimate population abundance, survival, and productivity. The IPM abundance estimates for data from 1975–2018 were less variable than annual mid-winter survey counts or Lincoln estimates, presumably reflecting better accounting for observer error and incorporation of demographic estimates by the IPM. Posterior estimates of adult survival were high (0.77–0.87), and harvest rates of adults and juveniles were positively correlated with more liberal hunting regulations (i.e., hunting days and the daily bag limit). Productivity was variable, with the percent of juveniles in the winter population ranging from 1% to >40%. We found no evidence for environmental relationships with productivity. Using IPM-predicted population abundances rather than mid-winter survey counts alone would have meant fewer annual changes to hunting regulations since 2004. Use of the IPM could improve harvest management for Atlantic brant by providing the ability to predict abundance before annual hunting regulations are set, and by providing more stable hunting regulations, with fewer annual changes. © 2021 The Wildlife Society.     

Survival,site fidelity,and the population dynamics of Piping Plovers in Saskatchewan

ABSTRACT To conserve threatened species, managers require predictions about the effects of natural and anthropogenic factors on population growth that in turn require accurate estimates of survival, birth, and dispersal rates, and their correlation with natural and anthropogenic factors. For Piping Plovers (Charadrius melodus), fledging rate is often more amenable to management than adult survival, and population models can be used to estimate the productivity (young produced per breeding female) necessary to maintain or increase populations for given levels of survival. We estimated true survival and site fidelity of adult and subadult (from fledging to second year) Piping Plovers breeding in Saskatchewan using mark‐resight data from 2002 to 2009. By estimating true survival rather than apparent survival (which is confounded with permanent emigration), we were able to provide more accurate projections of population trends. Average adult and subadult survival rates during our study were 0.80 and 0.57, respectively. Adult survival declined over time, possibly due in part to the loss of one breeding site to flooding. Average adult and subadult site fidelity were 0.86 and 0.46, respectively. Adult site fidelity declined during our study at two study sites, most strongly at the flooded site. Male and female Piping Plovers had similar survival rates, but males had greater site fidelity than females in some years. Based on our survival estimates, productivity needed for a stationary population was 0.75, a benchmark used for plover management on the Atlantic Coast, but not previously estimated for Prairie Canada. In stochastic simulations incorporating literature‐based variation in survival rates, productivity needed for a stationary population increased to 0.86, still lower than that previously estimated for western populations. Mean productivity for our study sites ranged from 0.87 to 0.96 fledged young per pair. Our results suggest that fledging rates of Piping Plovers in Saskatchewan were sufficient to ensure a stationary or increasing population during our study period. However, large‐scale habitat changes such as drought or anthropogenic flooding may lead to dispersal of breeding adults and possibly mortality that will increase the fledging rate needed for a stationary population.     

Population Estimation Techniques for Lekking Species

Abstract: With the decline of many lekking species, the need to develop a rigorous population estimation technique is critical for successful conservation and management. We employed mark—resight methods to estimate population size for 2 lekking species: greater sage-grouse (Centrocercus urophasianus) and Gunnison sage-grouse (Centrocercus minimus). We evaluated 2 different estimators: Bowden's estimator and the mixed logit-normal mark—resight model. We captured and marked 75 greater sage-grouse. We counted marked and unmarked birds as they attended 15 known leks. We used 36 and 37 marked Gunnison sage-grouse to estimate population size in 2003 and 2004, respectively. We observed marked and unmarked Gunnison sage-grouse daily as they attended 6 leks in 2003 and 3 leks in 2004. Based on our examination of the assumptions of each mark—resight estimator, relative to behavior and biology of these species, we concluded the mixed logit-normal mark—resight model is preferred. We recommend wildlife managers employ mark—resight approaches when statistically rigorous population estimates are required for management and conservation of lekking species.     

Bigger is better: age class-specific survival rates in long-lived turtles increase with size

Vital rates for small, non-breeding individuals are important components of population dynamics for many species, but often individuals of these sizes are difficult to locate, capture, and track. As such, biologists frequently lack reliable estimates of juvenile survival because sample sizes and recapture rates for this life stage are low. Long-lived animals often take many years to reach sexual maturity and spend much of this time in the smaller size classes, making them sensitive to changes in survival rates. We estimated the survival rates of all size classes for the northern map turtle (Graptemys geographica) using a mark-recapture dataset with >3,500 captures from 2019–2021 and 210 nests from 2018–2021. As turtle size increased, annual survival probability increased regardless of sex. Estimated annual survival probability for turtles >18 cm long (i.e., adult females >15 years) was about 0.95, over 4 times higher than turtles that were 3 cm long (i.e., hatchlings <1 year; 0.22 annual survival probability). Although we did not observe a difference in survival probability between sexes of any size class, adult females are nearly twice the size of adult males, leading to an increased annual survival probability for females of 0.95, compared to 0.80 for males. Changes in adult survival had the greatest influence on population estimates over time, with temporary decreases, such as those due to poaching or an environmental disaster, potentially leading to unrecoverable decreases in the overall population size. Our study provides detailed survival rates for all size classes in a long-lived turtle, which are necessary to assess population stability and can be used to determine the most effective conservation or management practices.     

Grizzly bear population vital rates and trend in the Northern Continental Divide Ecosystem,Montana

We estimated grizzly bear (Ursus arctos) population vital rates and trend for the Northern Continental Divide Ecosystem (NCDE), Montana, between 2004 and 2009 by following radio-collared females and observing their fate and reproductive performance. Our estimates of dependent cub and yearling survival were 0.612 (95% CI = 0.300–0.818) and 0.682 (95% CI = 0.258–0.898). Our estimates of subadult and adult female survival were 0.852 (95% CI = 0.628–0.951) and 0.952 (95% CI = 0.892–0.980). From visual observations, we estimated a mean litter size of 2.00 cubs/litter. Accounting for cub mortality prior to the first observations of litters in spring, our adjusted mean litter size was 2.27 cubs/litter. We estimated the probabilities of females transitioning from one reproductive state to another between years. Using the stable state probability of 0.322 (95% CI = 0.262–0.382) for females with cub litters, our adjusted fecundity estimate (m_x) was 0.367 (95% CI = 0.273–0.461). Using our derived rates, we estimated that the population grew at a mean annual rate of approximately 3% (λ = 1.0306, 95% CI = 0.928–1.102), and 71.5% of 10,000 Monte Carlo simulations produced estimates of λ > 1.0. Our results indicate an increasing population trend of grizzly bears in the NCDE. Coupled with concurrent studies of population size, we estimate that over 1,000 grizzly bears reside in and adjacent to this recovery area. We suggest that monitoring of population trend and other vital rates using radioed females be continued. © 2011 The Wildlife Society.     

First demographic insights on historically harvested and poorly known male sperm whale populations off the Crozet and Kerguelen Islands (Southern Ocean)

Age and sex dependent spatial segregation has resulted in limited knowledge of the ecology and demography of sperm whale adult males feeding seasonally in high latitudes. This study focused on adult males interacting with the Patagonian toothfish (Dissostichus eleginoides) fishery operating off the Kerguelen and Crozet Archipelagos. Demographic parameters were estimated using a 10‐yr‐long photo‐identification data set paired with multistate closed robust design capture‐mark‐recapture models. The examination of a set of 29,078 photographs taken from fishing vessels during sperm whale depredation events resulted in identification of 295 individuals with nine visiting both study areas. Dispersal between both study regions was estimated to be 1% per year. The mean annual number of interacting sperm whales was estimated to n = 82 (95% CI 58–141) in Crozet and n = 106 (95% CI 76–174) in Kerguelen. Transient proportions were 13% in Crozet and 26% in Kerguelen. Corrected for transience, apparent survival estimates were 0.953 (95% CI 0.890–0.993) in Crozet, and 0.911 (95% CI 0.804–0.986) in Kerguelen. These survival and population size estimates are the first for depredating adult males in high latitudes, and can be used in evaluating the current conservation status of this historically harvested stock and to investigate depredation trends in 35 both Crozet and Kerguelen Islands.     

Using multiple data types and integrated population models to improve our knowledge of apex predator population dynamics

Current management of large carnivores is informed using a variety of parameters, methods, and metrics; however, these data are typically considered independently. Sharing information among data types based on the underlying ecological, and recognizing observation biases, can improve estimation of individual and global parameters. We present a general integrated population model (IPM), specifically designed for brown bears (Ursus arctos), using three common data types for bear (U. spp.) populations: repeated counts, capture–mark–recapture, and litter size. We considered factors affecting ecological and observation processes for these data. We assessed the practicality of this approach on a simulated population and compared estimates from our model to values used for simulation and results from count data only. We then present a practical application of this general approach adapted to the constraints of a case study using historical data available for brown bears on Kodiak Island, Alaska, USA. The IPM provided more accurate and precise estimates than models accounting for repeated count data only, with credible intervals including the true population 94% and 5% of the time, respectively. For the Kodiak population, we estimated annual average litter size (within one year after birth) to vary between 0.45 [95% credible interval: 0.43; 0.55] and 1.59 [1.55; 1.82]. We detected a positive relationship between salmon availability and adult survival, with survival probabilities greater for females than males. Survival probabilities increased from cubs to yearlings to dependent young ≥2 years old and decreased with litter size. Linking multiple information sources based on ecological and observation mechanisms can provide more accurate and precise estimates, to better inform management. IPMs can also reduce data collection efforts by sharing information among agencies and management units. Our approach responds to an increasing need in bear populations’ management and can be readily adapted to other large carnivores.     

Monitoring populations of Western Sandpipers and Pacific Dunlins during northward migration on the Fraser River Delta,British Columbia, 1991–2013

The Fraser River Delta in British Columbia, Canada, is a globally significant stopover site for shorebirds, but the population status and trends of many species that use the site remain uncertain. We describe an ongoing program to monitor population trends of the two most abundant species, Western Sandpipers (Calidris mauri) and Dunlins (Calidris alpina), during northward migration. Counts of these species were conducted at a mudflat where large flocks assembled at mid‐tide from 15 April to 15 May, 1991–2013, and we estimated species‐specific counts as the product of daily total flock counts and species proportions obtained during supplementary sampling. The median peak count of both species combined was 177,000 birds, and occurred between 24 April and 3 May. Ratios (proportions) of the two species followed a predictable pattern during the migration period, with a low proportion of Western Sandpipers (3%–20%) in flocks before 20 April, followed by a rapid increase to 80%–100% between 25 April and 10 May and a variable decrease to 30%–80% by 15 May. Mean counts of Western Sandpipers showed no significant trend over the study period. Mean counts of Dunlins showed a non‐linear trend, decreasing until 2001 and then increasing to 2013. Bias and random error in field counts were quantified by comparing field counts to counts made from photographs taken during surveys, and analysis revealed that field counts had a downward, but predictable, bias, accounting for >90% of birds present, with a stochastic error rate of 28.0%. Uncertainty in total population estimates was high after accounting for the effect of length of stay and sampling error. Population estimates suggested that 600,000 Western Sandpipers and 200,000 Dunlins typically passed through the site during northward migration. Our estimates indicate the usefulness of daily counts at major stopover sites during northward migration as an effective tool for monitoring shorebird populations, and underscore the need for conserving such sites.     

Evaluation of Bear Rub Surveys to Monitor Grizzly Bear Population Trends

Abstract: Wildlife managers need reliable estimates of population size, trend, and distribution to make informed decisions about how to recover at-risk populations, yet obtaining these estimates is costly and often imprecise. The grizzly bear (Ursus arctos) population in northwestern Montana, USA, has been managed for recovery since being listed under the United States Endangered Species Act in 1975, yet no rigorous data were available to evaluate the program's success. We used encounter data from 379 grizzly bears identified through bear rub surveys to parameterize a series of Pradel model simulations in Program MARK to assess the ability of noninvasive genetic sampling to estimate population growth rates. We evaluated model performance in terms of 1) power to detect gender-specific and population-wide declines in population abundance, 2) precision and relative bias of growth rate estimates, and 3) sampling effort required to achieve 80% power to detect a decline within 10 years. Simulations indicated that ecosystem-wide, annual bear rub surveys would exceed 80% power to detect a 3% annual decline within 6 years. Robust-design models with 2 simulated surveys per year provided precise and unbiased annual estimates of trend, abundance, and apparent survival. Designs incorporating one survey per year require less sampling effort but only yield trend and apparent survival estimates. Our results suggest that systematic, annual bear rub surveys may provide a viable complement or alternative to telemetry-based methods for monitoring trends in grizzly bear populations.     

Toward reliable population density estimates of partially marked populations using spatially explicit mark–resight methods

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Who are we sampling? Apparent survival differs between methods in a secretive species

Survival is a fundamental parameter in population dynamics with increasing importance in the management and conservation strategies of wildlife populations. Survival probability in vertebrates is usually estimated by live‐encounter data obtained by means of physical mark–capture–recapture protocols. Non‐invasive acoustic marking relying on individual‐specific features of signals has been alternatively applied as a marking technique, especially in secretive species. Nevertheless, to date no research has compared survival rate estimates obtained by acoustic and physical marking. We estimated half‐yearly and annual survival and recapture rates of a secretive and threatened passerine, the Dupont's lark Chersophilus duponti, using two separate live‐encounter data sets of males collected simultaneously by physical and acoustic marking in the same study area. The separate analysis of both methods led to different model structures, since transient individuals had to be accounted for in the acoustic marking but not in the physical marking data set. Furthermore, while reencounter probabilities did not differ between methods, survival estimates employing physical marking were lower than those obtained acoustically, especially between the postbreeding and the breeding period when the apparent survival of colour‐banded birds was twice as low as for acoustic marking. The combination of marking methods suggested the existence of different subsets of individuals differentially sampled within the population: whereas colour‐banded males seemed to represent the territorial fraction of the population, both resident and floater individuals were probably detected by acoustic marking. Using traditional mark–recapture methods exclusively could have misled our estimates of survival rates, potentially affecting prospective predictions of population dynamics. Acoustic marking has been poorly applied in mark–recapture studies, but might be a powerful complement to obtain accurate estimates of fundamental demographic parameters such as survival and dispersal.     

A comparison of methods used to count the elephant population of the Addo Elephant National Park, South Africa

Evaluation of alternative techniques used to estimate elephant population sizes is important in order to assess the accuracy of the results obtained, upon which management decisions may be based. Data from annual helicopter surveys carried out in the Addo Elephant National Park (1978–97) are compared with registration counts obtained from intensive ground surveys in which all elephants within the park are individually known. On average, total population size estimated in aerial surveys is 8.0% lower than registration counts (n₁₉₉₇ = 251), aerial calf (< 1 year) counts are 48.8% lower than registration counts, and aerial carcass counts are 50% below the total number of deaths documented in ground surveys. Registration counts provide more accurate demographic data than aerial surveys, the results of which are shown to vary widely and unpredictably, thus compromising their value. Where population estimates rely exclusively on aerial surveys, replicate counts are recommended in order to generate confidence intervals.     

When and where to count? Implications of migratory connectivity and nonbreeding distribution to population censuses in a migratory bird population

Migratory connectivity is a metric of the co-occurrence of migratory animals originating from different breeding sites, and like their spatial dispersion, can vary substantially during the annual cycle. Together, both these properties affect the optimal times and sites of population censusing. We tracked taiga bean geese (Anser fabalis fabalis) during 2014–2021 to study their migratory connectivity and nonbreeding movements and determine optimal periods to assess the size of their main flyway population. We also compared available census data with tracking data, to examine how well two existing censuses covered the population. Daily Mantel's correlation between breeding and nonbreeding sites lay between 0 and 0.5 during most of the nonbreeding season, implying birds from different breeding areas were not strongly separated at other times in the annual cycle. However, the connectivity was higher among birds from the westernmost breeding areas compared to the birds breeding elsewhere. Daily Minimum Convex Polygons showed tracked birds were highly aggregated at census times, confirming their utility. The number of tracked birds absent at count sites during the censuses however exceeded numbers double-counted at several sites, indicating that censuses might have underestimated the true population size. Our results show that connectivity can vary in different times during the nonbreeding period, and should be studied throughout the annual cycle. Our results also confirm previous studies, which have found that estimates using marked individuals usually produce higher population size estimates than total counts. This should be considered when using total counts to assess population sizes in the future.     

Apparent Survival and Population Growth of Snowy Plovers in Coastal Northern California

ABSTRACT An accurate understanding of factors influencing survival and how they affect population growth are required to determine the best conservation strategies for small populations, especially near the limit of a species' range. We estimated adult and juvenile survival for a small population of the threatened western snowy plover (Charadrius alexandrinus nivosus) in coastal northern California over 7 years (2001–2007). We also evaluated population structure and growth to determine the relative importance of immigration and local recruitment. Apparent survival for adult males (φ = 0.61 ± 0.08) was greater than that of adult females (φ = 0.50 ± 0.11), and survival of adults was greater than for juveniles (φ = 0.40 ± 0.06). An algebraic assessment of population growth (Λ) revealed that fecundity and survival were insufficient to maintain the population (Λ = 0.66–0.77), whereas estimates based on consecutive annual counts (Λ = 0.96 ± 0.26) and a Pradel model (Λ = 0.92 ± 0.11) suggested the population was more stable. These results, combined with annual variation in the number of newly marked plovers, indicate that the local population was maintained by immigration and can be classified as a sink. Management actions aimed at increasing fecundity, including predator control and greater restrictions on human activity, may be necessary to maintain this population; actions aimed at increasing adult survival are more challenging.     

Estimates of Survival from Radiotelemetry: a Response to Guthery and Lusk

Abstract: Radiotelemetry has become an important and frequently used tool in wildlife research. Inferences drawn from radiotelemetry data depend on the assumption that the radiotransmitters are not influencing parameter(s) of interest. An article by Guthery and Lusk (2004) in the Wildlife Society Bulletin questioned the validity of this assumption for estimating survival rates of northern bobwhites (Colinus virginianus) using radiotelemetry data. In this evaluation, we address technical and philosophical flaws in Guthery and Lusk's (2004) critique of northern bobwhite studies utilizing radiotelemetry. They concluded that biologists should be skeptical of radiotelemetry studies and they advised researchers to design studies to address potential biases caused by radiotransmitters using independent data. Although we agree that researchers are responsible for testing key assumptions of their techniques, we believe Guthery and Lusk's (2004) conclusions were not well supported and were based on tenuous assumptions. Guthery and Lusk (2004) calculated the level of productivity (given as a fall age ratio) required to balance a simple population model that contained published estimates of annual survival and assumed an annual finite population growth rate of 1.0. We review their population model and show that the relationship between an annual survival rate and fall age ratio is nonlinear. This nonlinearity can lead to biased estimates of a fall age ratio, especially at lower values of annual survival. We also question the validity of using fall age ratios as an estimator of productivity. Further, we suggest that this assessment of a radiotransmitter effect from a survival rate itself is not appropriate. This rate can be depressed (or elevated) for a variety of reasons not related to the influence of radiotransmitters. In addition, Guthery and Lusk (2004) assumed that daily survival rates (as calculated from both annual and seasonal published estimates) were constant throughout the year; thus, they scaled daily survival rates from seasonal to annual estimates. Further, their meta-analysis was hindered by temporal pseudoreplication and a lack of independence among the observations used in the analysis. We conclude the weight of the evidence presented by Guthery and Lusk (2004) is not as strong as they claim because it fails to meet the test of sufficient causation. While scientists should always be skeptical and critical of assumptions of all methods employed in wildlife research, more rigorous tests are necessary before we discredit a valuable technique without sufficient empirical evidence.     

Current status and recent trend of the Eurasian Woodcock Scolopax rusticola as a breeding bird in Britain

Capsule The breeding Woodcock population in Britain in 2013 was estimated at 55?241 males (95% CL: 41?806–69?004), suggesting a large-scale decline that is supported by 2 additional sources of data.

Aims To provide an updated estimate of the size of Britain's breeding Woodcock population, measure recent trends and identify spatial patterns of change.

Methods Displaying male Woodcock were surveyed at a stratified sample of 834 randomly selected sites. Population estimates were compared with a baseline survey conducted in 2003 and the trend with data from annual Woodcock counts (2003–13) and Bird Atlas 2007–11.

Results Woodcock were estimated to be present at 22% of 1?×?1?km squares containing ≥10?ha of woodland, compared to 35% in 2003. The British population estimate fell by 29% between 2003 and 2013. The Atlas suggests that presence at the 10?×?10?km scale has declined by 56% between 1970 and 2010. Both data sources suggest regional variation in the rate of decline, with losses greatest in the West and South.

Conclusion The Woodcock's population size and breeding range appear to be declining severely across Britain. Regional variation in the rate of decline might be explained by the distribution of large continuous woodlands.     

Comparison of Methods for Estimating Bird Abundance and Trends From Historical Count Data

Abstract: The use of bird counts as indices has come under increasing scrutiny because assumptions concerning detection probabilities may not be met, but there also seems to be some resistance to use of model-based approaches to estimating abundance. We used data from the United States Forest Service, Southern Region bird monitoring program to compare several common approaches for estimating annual abundance or indices and population trends from point-count data. We compared indices of abundance estimated as annual means of counts and from a mixed-Poisson model to abundance estimates from a count-removal model with 3 time intervals and a distance model with 3 distance bands. We compared trend estimates calculated from an autoregressive, exponential model fit to annual abundance estimates from the above methods and also by estimating trend directly by treating year as a continuous covariate in the mixed-Poisson model. We produced estimates for 6 forest songbirds based on an average of 621 and 459 points in 2 physiographic areas from 1997 to 2004. There was strong evidence that detection probabilities varied among species and years. Nevertheless, there was good overall agreement across trend estimates from the 5 methods for 9 of 12 comparisons. In 3 of 12 comparisons, however, patterns in detection probabilities potentially confounded interpretation of uncorrected counts. Estimates of detection probabilities differed greatly between removal and distance models, likely because the methods estimated different components of detection probability and the data collection was not optimally designed for either method. Given that detection probabilities often vary among species, years, and observers investigators should address detection probability in their surveys, whether it be by estimation of probability of detection and abundance, estimation of effects of key covariates when modeling count as an index of abundance, or through design-based methods to standardize these effects.     

Assessing Landbird Monitoring Programs and Demographic Causes of Population Trends

Abstract: Population trend data from the North American Breeding Bird Survey (BBS) have been used to identify conservation priorities and justify major conservation initiatives. Yet the BBS has been criticized for potential habitat bias and reliance on abundance indices to estimate trends. We compared 1992–2003 BBS trend estimates to trend estimates derived from bird-banding data collected as part of the Monitoring Avian Productivity and Survivorship (MAPS) program for 36 wood warbler species. Similarity in trends between the 2 monitoring programs at the survey-wide and program-wide scales suggested that each program can provide accurate trend information. The MAPS program, however, was designed primarily to complement (rather than duplicate) count-based efforts, such as the BBS, by providing estimates or indices of demographic rates. Demographic data from MAPS can be used to lend insight into proximate (demographic) causes of population trends and inform management. We illustrate this with analyses of 1992–2003 MAPS data for yellow warbler (Dendroica petechia). We used reverse-time capture-recapture models to evaluate importance of new recruits (including immigrating adults and young from the previous year) relative to surviving adults in explaining variation in trend among BBS physiographic strata. We included the number of young per adult captured (an index of productivity) as a covariate in models to assess effects of productivity on trends. Survival was the key demographic driver of recent population trends. Comparison of MAPS productivity indices and adult apparent survival rate estimates to BBS trend estimates largely confirmed this inference. We suggest that increased MAPS coverage, better coordination between MAPS and the BBS, and continued development of analytical methods that link the 2 programs will enhance the value of these monitoring efforts to land managers and conservation planners working at a variety of spatial scales.