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1 January 2011 Analysis of the North American Breeding Bird Survey Using Hierarchical Models
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We analyzed population change for 420 bird species from the North American Breeding Bird Survey (BBS) using a hierarchical log-linear model and compared the results with those obtained through route-regression analysis. Survey-wide trend estimates based on the hierarchical model were generally more precise than estimates from the earlier analysis. No consistent pattern of differences existed in the magnitude of trends between the analysis methods. Survey-wide trend estimates changed substantially for 15 species between route-regression and hierarchical-model analyses. We compared regional estimates for states, provinces, and Bird Conservation Regions; differences observed in these regional analyses are likely a consequence of the route-regression procedure's inadequate accommodation of temporal differences in survey effort. We used species-specific hierarchical-model results to estimate composite change for groups of birds associated with major habitats and migration types. Grassland, aridland, and eastern-forest-obligate bird species declined, whereas urban—suburban species increased over the interval 1968–2008. No migration status group experienced significant changes, although Nearctic—Neotropical migrant species showed intervals of decline and permanent resident species increased almost 20% during the interval. Hierarchical-model results better portrayed patterns of population change over time than route-regression results. We recommend use of hierarchical models for BBS analyses.

© 2011 by The American Ornithologists' Union. All rights reserved. Please direct all requests for permission to photocopy or reproduce article content through the University of California Press's Rights and Permissions website,
John R. Sauer and William A. Link "Analysis of the North American Breeding Bird Survey Using Hierarchical Models," The Auk 128(1), 87-98, (1 January 2011).
Received: 2 November 2009; Accepted: 1 September 2010; Published: 1 January 2011

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