Figure 2 - uploaded by Bryce W Robinson
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Spatial distribution by county of unique records of Anna's Hummingbird in Idaho from the Idaho Bird Records Committee (IBRC) database and www.eBird. org, by three intervals: 1976-2019 (23 individuals), 2001-2010 (19 individuals), and 2011-2019 (126 individuals). Note the scale for 2011-2019 is log transformed to facilitate interpretation relative to the previous intervals. Counties with the most Anna's Hummingbird records have relatively high human populations, whereas many counties lacking records have low human population. Anna's Hummingbird illustration by Bryce W. Robinson.
Source publication
Increased urbanization and supplementary feeding are implicated in driving the expansion of the range of the Anna’s Hummingbird (Calypte anna). In many areas this range expansion has been well described, but the recent expansion of the northeastern limit of the nonbreeding distribution, in winter in Idaho, has not yet been summarized. Using data fr...
Contexts in source publication
Context 1
... eBird, birders reported 151 independent winter records from 1976-2020 (mean 3.4, range 0-29 annually; Figure 1). The majority of these records were near two towns at lower elevations, Boise (832 m) and Lewiston (227 m), and mostly from October to February ( Figure 2). Although most frequent in late fall/winter (October-February), reports through eBird now encompass every month of the year (March-September 2006-2014, mean 2.3, range 1-7 annually; 2015-2020, mean 13.5, range 10-23 annually). ...
Context 2
... 1 (continued). increase since 2011 in both the spatial distribution and numbers of Anna's Hummingbirds wintering in Idaho (Figure 2). This trend is biased toward centers of human population, whereas many sparsely populated counties lack records of the species. ...
Context 3
... solicited homeowner reports and banding effort provided a more complete picture of the number of Anna's Hummingbirds present in Idaho during the nonbreeding season. By overlaying all sources, we updated our understanding of the magnitude of the numbers of hummingbirds wintering in Idaho (Figure 2), and gained fine-scale data that may clarify the patterns and processes of the range expansion. ...
Context 4
... eBird, birders reported 151 independent winter records from 1976-2020 (mean 3.4, range 0-29 annually; Figure 1). The majority of these records were near two towns at lower elevations, Boise (832 m) and Lewiston (227 m), and mostly from October to February ( Figure 2). Although most frequent in late fall/winter (October-February), reports through eBird now encompass every month of the year (March-September 2006-2014, mean 2.3, range 1-7 annually; 2015-2020, mean 13.5, range 10-23 annually). ...
Context 5
... 1 (continued). increase since 2011 in both the spatial distribution and numbers of Anna's Hummingbirds wintering in Idaho (Figure 2). This trend is biased toward centers of human population, whereas many sparsely populated counties lack records of the species. ...
Context 6
... solicited homeowner reports and banding effort provided a more complete picture of the number of Anna's Hummingbirds present in Idaho during the nonbreeding season. By overlaying all sources, we updated our understanding of the magnitude of the numbers of hummingbirds wintering in Idaho (Figure 2), and gained fine-scale data that may clarify the patterns and processes of the range expansion. ...
Citations
... This first documented successful breeding of the Anna's Hummingbird in Idaho provides a marker on the chronology of the species' range expansion into the state. This chronology has thus far been well documented through the methods outlined by Pollock et al. (2021). Continued focus and documentation of the increase in numbers, as well as of further instances of breeding, will provide fine-scale details to the ongoing range expansion experienced by this species since the urbanization of the West accelerated in the middle of the 20th century. ...
