4/3/2024 0 Comments Us bird population density map![]() ![]() The fact box summarises at-a-glance the Atlas sample sizes and other data statistics including the minimum and maximum elevations that each species was recorded on point counts and/or rare species forms, and the conservation status (in 2014) and population trends (if available, with links to sources) for each species. This standard feature opens by clicking the box at the top right of the account. Species names are provided in English, French, and Latin, following the American Ornithologists’ Union’s AOU Checklist of North and Middle American Birds, up to the 55th supplement (2014). Outlined below are the main elements of a typical account, listed in order of appearance. We have purposely avoided providing detailed natural history information that is already well presented elsewhere ( e.g., in Campbell et al.‘s four volume series The Birds of British Columbia 1990-2001, except where it is pertinent to interpreting atlas results. The primary purpose of the species accounts is to help the reader interpret the maps, graphs and related data from the British Columbia Breeding Bird Atlas, together with just enough natural history information from other sources to put those results into a meaningful context. ? 2009 British Ecological Society.This section provides interpretation guidance for the accounts describing the 320 or so species for which breeding evidence was reported in at least one 10-km square during the atlas period (2008–2012). We believe these requirements can be met, with suitable field methods, for a significant number of songbird species. The method requires that individuals detected at the same place are acoustically distinguishable and all individuals vocalize during the recording interval, or that the per capita rate of vocalization is known. The necessary equipment is simple and readily available as few as two microphones may provide adequate estimates, given spatial replication. Our method for estimating animal population density from acoustic signals fills a gap in the census methods available for visually cryptic but vocal taxa, including many species of bird and cetacean. The fitted model predicts sound attenuation of 0?11 dB m -1 (SE 0?01 dB m -1) in excess of losses from spherical spreading. The resulting estimates of the density of singing males (0?19 ha -1 SE 0?03 ha -1) were consistent with estimates of the adult male population density from mist-netting (0?36 ha -1 SE 0?12 ha -1). We modelled average power from spectrograms of ovenbird songs measured within a window of 0?7 s duration and frequencies between 42 Hz. We applied this extension of SECR to data from an acoustic survey of ovenbird Seiurus aurocapilla density in an eastern US deciduous forest with multiple four-microphone arrays. ![]() ![]() We have extended SECR to use uncalibrated information from acoustic signals on the distance to each source. ![]() Spatially explicit capture-recapture (SECR) is a statistical methodology that addresses jointly the second and third parts of the problem. The problem has several parts - distinguishing individuals, adjusting for individuals that are missed, and adjusting for the area sampled. Although songs, calls and other sounds are often used for population assessment, as in bird point counts and hydrophone surveys of cetaceans, there are few rigorous methods for estimating population density from acoustic data. Many animal species are detected primarily by sound. ![]()
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