Population Status of the Eastern Phoebe in South-Central North Carolina: Breeding Increase at Water-Based Anthropogenic Sites Congruent with Breeding Bird Survey (BBS) and Christmas Bird Count (CBC) Data

The Varied Thrush (Ixoreus naevius), an endemic species of the Pacific Northwest of North America, shows dramatic year-to-year changes in wintering abundance. These changes have not, however, been systematically examined using standardized data. Using Project FeederWatch data from 1988–1989 to 1994–1995 we found that Varied Thrushes showed a biennial cyclic change in abundance within most of their normal wintering range. This cyclic pattern was also evident in Christmas Bird Count and Breeding Bird Survey data from the same time period. There was no difference in the extent or location of the winter range or in the distribution of elevations of Varied Thrush records between years of high and low abundance. More feeders had single Varied Thrushes in years of high abundance than in years of low abundance. Longer term (1969–1970 to 1994–1995) Christmas Bird Count and Breeding Bird Survey data showed a more variable pattern, with abundance peaks every 2–3 years. The number of vagrant Varied Thrushes from eastern North America reported in Audubon Field Notes winter season reports was not correlated with abundance in the normal wintering and breeding areas but was correlated with the number of Varied Thrushes tallied on southern California Christmas Bird Counts. These results suggest that patterns of vagrancy in Varied Thrushes are largely independent of population changes within the normal wintering area.

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Estimating breeding bird survey trends and annual indices for Canada: how do the new hierarchical Bayesian estimates differ from previous estimates?

The Canadian Field-Naturalist ◽

10.22621/cfn.v128i2.1565 ◽

2014 ◽

Vol 128 (2) ◽

pp. 119 ◽

Cited By ~ 16

Author(s):

Adam C. Smith ◽

Marie-Anne R. Hudson ◽

Constance Downes ◽

Charles M. Francis

Keyword(s):

Statistical Models ◽

Bayesian Model ◽

Previous Model ◽

Hierarchical Bayesian ◽

Hierarchical Bayesian Model ◽

Breeding Bird Survey ◽

Population Status ◽

Breeding Bird ◽

New Model ◽

Bird Survey

Canadian data from the North American Breeding Bird Survey (BBS) provide information on the population status and trends for over 300 species that regularly breed in Canada. Since the first assessments were made in the mid-1970s, both the dataset and the suite of statistical tools and techniques available to researchers have grown. As a result, Canadian BBS trend estimates have been derived from numerous statistical models. Because the BBS data are relatively complex, different statistical models can generate different trend and status estimates from the same data. In 2013, Environment Canada’s Canadian Wildlife Service began producing BBS status and trend estimates using a hierarchical Bayesian model. To give users of BBS trends and annual indices of abundance a better understanding of these estimates, we demonstrate and explain some of the similarities and differences between the new hierarchical Bayesian estimates and those from the previous model; discuss the philosophical and inferential consequences of estimating trends with the new model; and describe how the hierarchical Bayesian model differs from the model currently used in the United States. Overall, trends and annual indices from the new model are generally similar to estimates from the previous model; however, they are more precise, less variable among years, better represent the spatial variation across Canada in population status, and allow for more intuitive and useful assessments of uncertainty.

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Method learning caused a first‐time observer effect in a newly started breeding bird survey

Bird Study ◽

10.1080/00063650902791991 ◽

2009 ◽

Vol 56 (2) ◽

pp. 253-258 ◽

Cited By ~ 38

Author(s):

Frederic Jiguet

Keyword(s):

Breeding Bird Survey ◽

Breeding Bird ◽

Observer Effect ◽

Bird Survey ◽

First Time

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Estimation Of Annual Indexes of Abundance and Trend From The American Woodcock Singing-Ground Survey: Comparison Of 4 Models

Journal of Fish and Wildlife Management ◽

10.3996/jfwm-20-079 ◽

2021 ◽

Author(s):

John R Sauer ◽

William A. Link ◽

Mark E. Seamans ◽

Rebecca D. Rau

Keyword(s):

Population Change ◽

Breeding Bird Survey ◽

Breeding Bird ◽

Alternative Models ◽

American Woodcock ◽

Ground Survey ◽

Bird Survey ◽

Leave One Out ◽

S Model ◽

D Model

Status and trends of American Woodcock Scolopax minor populations in the eastern and central US and Canada are monitored via a Singing-ground Survey , conducted just after sunset along roadsides in spring. Annual analyses of the survey produce estimates of trend and annual indexes of abundance for 25 states and provinces, eastern and central management regions, and survey-wide. In recent years, a log-linear hierarchical model that defines year effects as random effects in the context of a slope parameter (the S Model) has been used to model population change. Recently, alternative models have been proposed for analysis of Singing-ground Survey data. Analysis of a similar roadside survey, the North American Breeding Bird Survey , has indicated that alternative models are preferable for almost all species analyzed in the Breeding Bird Survey. Here, we use leave-one-out cross validation to compare model fit for the present Singing-ground Survey model to fits of three alternative models, including a model that describes population change as the difference in expected counts between successive years (the D model) and two models that include t -distributed extra-Poisson overdispersion effects (H models) as opposed to normally-distributed extra-Poisson overdispersion. Leave-one-out cross validation results indicate that the D model was favored by the Bayesian predictive information criterion but a pairwise t -test indicated that model D was not significantly better-fitting to Singing-ground Survey data than the S model. The H models are not preferable to the alternatives with normally-distributed overdispersion. All models provided generally similar estimates of trend and annual indexes suggesting that, within this model set, choice of model will not lead to alternative conclusions regarding population change. However, as in Breeding Bird Survey analyses, we note a tendency for S model results to provide slightly more extreme estimates of trend relative to D models. We recommend use of the D model for future Singing-ground Survey analyses.

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