Controlling for Varying Effort in Count Surveys: An Analysis of Christmas Bird Count Data

1999 ◽  
Vol 4 (2) ◽  
pp. 116 ◽  
Author(s):  
William A. Link ◽  
John R. Sauer
Keyword(s):  
Count Data ◽  
Christmas Bird Count ◽  
Count Surveys

Effects of ENSO and PDO Events on Seabird Populations as Revealed by Christmas Bird Count Data

Waterbirds ◽  
2000 ◽  
Vol 23 (3) ◽  
pp. 416 ◽  
Author(s):  
Robert Vandenbosch
Keyword(s):  
Count Data ◽  
Christmas Bird Count

Atlas of wintering North American birds: an analysis of Christmas bird count data

1989 ◽  
Vol 26 (10) ◽  
pp. 26-5665-26-5665
Keyword(s):  
North American ◽  
Count Data ◽  
Christmas Bird Count

Combining Breeding Bird Survey and Christmas Bird Count Data to Evaluate Seasonal Components of Population Change in Northern Bobwhite

2008 ◽  
Vol 72 (1) ◽  
pp. 44-51 ◽  
Author(s):  
William A. Link ◽  
John R. Sauer ◽  
Daniel K. Niven
Keyword(s):  
Count Data ◽  
Population Change ◽  
Northern Bobwhite ◽  
Breeding Bird Survey ◽  
Breeding Bird ◽  
Christmas Bird Count ◽  
Bird Survey

scholarly journals Accounting for Surveyor Effort in Large-Scale Monitoring Programs

2018 ◽  
Vol 9 (2) ◽  
pp. 459-466 ◽  
Author(s):  
Kevin Aagaard ◽  
James E. Lyons ◽  
Wayne E. Thogmartin
Keyword(s):  
Count Data ◽  
Large Scale ◽  
Monitoring Program ◽  
Wildlife Monitoring ◽  
Multiple Sources ◽  
Christmas Bird Count ◽  
Monitoring Programs ◽  
Log Linear ◽  
High Degree ◽  
Survey Effort

AbstractAccounting for errors in wildlife surveys is necessary for reliable status assessments and quantification of uncertainty in estimates of population size. We apply a hierarchical log-linear Poisson regression model that accounts for multiple sources of variability in count data collected for the Integrated Waterbird Management and Monitoring Program during 2010–2014. In some large-scale monitoring programs (e.g., Christmas Bird Count) there are diminishing returns in numbers counted as survey effort increases; therefore, we also explore the need to account for variable survey duration as a proxy for effort. In general, we found a high degree of concordance between counts and effort-adjusted estimates of relative abundance from the Integrated Waterbird Management and Monitoring Program (x̄difference = 0.02%; 0.25% SD). We suggest that the model-based adjustments were small because there is only a weak asymptotic relationship with effort and count. Whereas effort adjustments are reasonable and effective when applied to count data from plots of standardized area, such adjustments may not be necessary when the area of sample units is not standardized and surveyor effort increases with number of birds present. That is, large units require more effort only when there are many birds present. The general framework we implemented to evaluate effects of varying survey effort applies to a wide variety of wildlife monitoring efforts.

scholarly journals Synchrony and Periodicity of Eruptions by Boreal Birds

The Condor ◽  
2001 ◽  
Vol 103 (4) ◽  
pp. 725-735 ◽  
Author(s):  
Walter D. Koenig
Keyword(s):  
North America ◽  
Count Data ◽  
Time Frame ◽  
Western North America ◽  
Loxia Curvirostra ◽  
Christmas Bird Count ◽  
Species Pairs ◽  
Seed Eating ◽  
Geographic Regions ◽  
The Relationship

Abstract I examined 38 years of Christmas Bird Count data in order to resolve conflicting earlier findings as to whether eruptions of boreal seed-eating birds are synchronized and occur at regular intervals. A total of 15 species was analyzed, including several largely insectivorous boreal species. Interspecific synchrony was common, with 34 species pairs (32% of a possible 105) statistically synchronous across all or part of North America and clusters of up to five species exhibiting significant synchrony in all pairwise combinations. Within-species synchrony was significant between eastern and western North America for five species. The relationship between interspecific synchrony and diet was weak and significantly higher among species in the same diet category in western North America only. Periodicity as measured by temporal autocorrelations in mean winter density at lags of up to three years was significant for eight of the species in at least one of the geographic regions; four of these (Red-breasted Nuthatch [Sitta canadensis], Red Crossbill [Loxia curvirostra], Common Redpoll [Carduelis flammea], and Pine Siskin [Spinus pinus]) exhibited a significant pattern of alternating cycles of low and high densities in at least one of the geographic regions analyzed. These results confirm that eruptions of boreal seed-eating birds are sometimes interspecifically synchronous events. However, the weak relationship with diet supports the hypothesis that factors in addition to food play an important role in both causing and synchronizing eruptions. Furthermore, synchrony varies dramatically through time, and thus conclusions regarding both the patterns and causes of eruptions are likely to differ depending on the time frame considered. Sincronía y Periodicidad de las Erupciones de Aves Boreales Resumen. Examiné 38 años de datos de los Conteos Navideños de Aves para resolver conflictos en hallazgos previos sobre si las erupciones de aves granívoras están sincronizadas y ocurren a intervalos regulares. Un total de 15 especies fue analizado, incluyendo varias especies boreales principalmente insectívoras. La sincronía interespecífica fue común, con 34 pares de especies (32% de 105 posibles) estadísticamente sincrónicas a través de todo o parte de América del Norte, y grupos de hasta cinco especies exhibiendo significativa sincronía en todas las combinaciones pareadas. La sincronía intraespecífica entre el Este y Oeste de América del Norte fue significativa para cinco especies. La relación entre sincronía interespecífica y dieta fue débil y sólo significativamente mayor entre especies en la misma categoría de dieta en el Oeste de América del Norte. La periodicidad, medida como la autocorrelación temporal de la densidad invernal promedio con un desfase temporal de hasta tres años, fue significativa para ocho de las especies en al menos una de las regiones geográficas; cuatro de estas especies (Sitta canadensis, Loxia curvirostra, Carduelis flammea y Spinus pinus) exhibieron un patrón significativo de alternancia de ciclos de baja y alta densidades en al menos una de las regiones geográficas analizadas. Estos resultados confirman que las erupciones de aves boreales granívoras a veces son eventos sincrónicos interespecíficos. Sin embargo, la débil relación con la dieta apoya la hipótesis que otros factores además del alimento juegan un rol importante tanto en causar como en sincronizar las erupciones. Más aún, la sincronía varía dramáticamente en el tiempo, y por ello las conclusiones sobre los patrones y las causas de las erupciones probablemente diferirán dependiendo de la escala temporal considerada.

Atlas of wintering north american birds: An analysis of christmas bird count data

1989 ◽  
Vol 4 (8) ◽  
pp. 253
Author(s):  
C.M. Perrins
Keyword(s):  
North American ◽  
Count Data ◽  
Christmas Bird Count

Regression Analysis of Count Data

1998 ◽  
Author(s):  
A. Colin Cameron ◽  
Pravin K. Trivedi
Keyword(s):  
Regression Analysis ◽  
Count Data

IRT-ZIP Modeling for Multivariate Zero-Inflated Count Data

2010 ◽  
Author(s):  
Lijuan Wang
Keyword(s):  
Count Data

Analyzing discontinuities in longitudinal count data: A multilevel generalized linear mixed model.

2020 ◽  
Author(s):  
James L. Peugh ◽  
Sarah J. Beal ◽  
Meghan E. McGrady ◽  
Michael D. Toland ◽  
Constance Mara
Keyword(s):  
Count Data ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Generalized Linear Mixed Model ◽  
Longitudinal Count Data
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