A test of the variable circular-plot method where exact density of a bird population was known

Nelson, Jay T.; Fancy, Steven G.

doi:10.1071/pc990139

Cited by 24 publications

(17 citation statements)

References 6 publications

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“…In addition to the extra time this step would take, it is biological folly to believe birds would return to their original locations while the observer is there. Nelson and Fancy (1999) also noted that such a practice likely still would underestimate bird density near the point. Movement of birds, although generally presumed to be away from an observer, in some species could be toward the observer (e.g., Emlen 1971).…”

Section: Feature Example Referencesmentioning

confidence: 99%

In Defense of Indices: The Case of Bird Surveys

2008

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: Indices to population size have come under increasing criticism in recent years, on the grounds that indices might not faithfully represent the entire population. Most criticisms involve surveys of birds, particularly those based on point counts, which is my focus here. A variety of quantitative methods have been developed to reduce the bias of point counts, such as distance sampling, multiple‐observer surveys, and time‐of‐detection methods. I argue that these developments are valuable, in that they enhance understanding of the detection process, but that their practical application may well be limited, likely to intensive studies focusing on a small number of species. These quantitative methods are not generally applicable to extensive, multiple‐species surveys. Although criticism of the thoughtless use of indices is welcome, their wholesale rejection is not.

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Section: Feature Example Referencesmentioning

confidence: 99%

In Defense of Indices: The Case of Bird Surveys

2008

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“…Only one field test of distance sampling applied to point‐count surveys, termed either point‐transect sampling or variable circular plots, has been conducted where exact density was known. As part of a reintroduction program for Omao ( Myadestes obscurus ), Nelson and Fancy (1999) tested this method by releasing 41 radio‐marked birds into unoccupied forest. Density estimates derived from variable circular plots provided unbiased estimates of true density and differed from true population size by ‐34 to +24%.…”

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confidence: 99%

A field test of the distance sampling method using Golden-cheeked Warblers

Peak¹

2011

Journal of Field Ornithology

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Criteria for delisting Golden‐cheeked Warblers (Dendroica chrysoparia) include protection of sufficient breeding habitat to ensure the continued existence of 1000 to 3000 singing males in each of eight recovery regions for ≥10 consecutive years. Hence, accurate abundance estimation is an integral component in the recovery of this species. I conducted a field test to determine if the distance sampling method provided unbiased abundance estimates for Golden‐cheeked Warblers and develop recommendations to improve the accuracy of estimates by minimizing the effects of violating this method's assumptions. To determine if observers could satisfy the assumptions that birds are detected at the point with certainty and at their initial locations, I compared point‐transect sampling estimates from 2‐, 3‐, 4‐, and 5‐min time intervals to actual abundance determined by intensive territory monitoring. Point‐transect abundance estimates were 15%, 29%, 43%, and 59% greater than actual abundance (N= 156) for the 2‐, 3‐, 4‐, and 5‐min intervals, respectively. Point‐transect sampling produced unbiased estimates of Golden‐cheeked Warbler abundance when counts were limited to 2 min (N= 154–207). Abundance estimates derived from point‐transect sampling were likely greater than actual abundance because observers did not satisfy the assumption that birds were detected at their initial locations due to the frequent movements and large territory sizes of male Golden‐cheeked Warblers. To minimize the effect of movement on abundance estimates, I recommend limiting counts of singing males to 2‐min per point. Counts for other species in similar habitats with similar behavior and movement patterns also should be limited to 2 min when unbiased estimates are important and conducting field tests of the point‐transect distance sampling method is not possible.

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“…However, we do not include those data in the analysis presented here (to maintain a consistent protocol over the entire study). We estimated distances to all birds (or groups of birds) encountered (Reynolds and others, 1980;Fancy, 1997;Nelson and Fancy, 1999;Rosenstock and others, 2002), except for a small number of individuals which were classified as 'flyovers' without any real connection to the habitat below them, to enable estimation and modeling of detection probability as a function of distance, and subsequent estimation of point-level avian densities others, 2001, 2004). …”

Section: Data Collectionmentioning

confidence: 99%

Landbird trends in national parks of the North Coast and Cascades Network, 2005-12

Saracco¹,

Holmgren²,

Wilkerson³

et al. 2014

Open-File Report

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For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprodTo order this and other USGS information products, visit http://store.usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.Suggested citation: Saracco, J.F., Holmgren, A.L., Wilkerson, R.L., Siegel, R.B., Kuntz, R.C., II, Jenkins, K.J., Happe, P.J., Boetsch, J.R., and Huff, M.H., 2014, Landbird trends in national parks of the North Coast and Cascades Network, 2005-12 Horizontal coordinate information is referenced to North American Datum of 1983 (NAD 83).Elevation, as used in this report, refers to distance above the vertical datum. Landbird Trends in AbstractNational parks in the North Coast and Cascades Network (NCCN) can fulfill vital roles as refuges for bird species dependent on late-successional forest conditions and as reference sites for assessing the effects of land-use and land-cover changes on bird populations throughout the larger Pacific Northwest region. Additionally, long-term monitoring of landbirds throughout the NCCN provides information that can inform decisions about important management issues in the parks, including visitor impacts, fire management, and the effects of introduced species. In 2005, the NCCN began implementing a network-wide Landbird Monitoring Project as part of the NPS Inventory and Monitoring Program. In this report, we discuss 8-year trends of bird populations in the NCCN, based on a sampling framework of point counts established in three large wilderness parks (Mount Rainier, North Cascades, and Olympic National Parks), 7-year trends at Lewis and Clark National Historical Park (sampled in 2006, 2008), and 5-year trends at San Juan Islands National Historical Park (sampled in 2007. Our analysis encompasses a fairly short time span for this long-term monitoring program. The first 2 years of the time series (2005 and 2006) were implemented as part of a limited pilot study that included only a small subset of the transects. The subsequent 6 years (2007-12) represent just a single cycle through 5 years of alternating panels of transects in the large parks, with the first of five alternating panels revisited for the first time in 2012. Of 204 transects that comprise the six sampling panels in the large parks, only 68 (one-third) have thus been eligible for revisit surveys (34 during every year after 2005, and an additional 34 only in 2012) and can contribute to our current trend estimates. We therefore initiated the current analysis with a primary go...

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A test of the variable circular-plot method where exact density of a bird population was known

Cited by 24 publications

References 6 publications

In Defense of Indices: The Case of Bird Surveys

In Defense of Indices: The Case of Bird Surveys

A field test of the distance sampling method using Golden-cheeked Warblers

Landbird trends in national parks of the North Coast and Cascades Network, 2005-12

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