Winter Survey Data Reveal Rangewide Decline in Evening Grosbeak Populations

Analysis of combined data sets yields trend estimates for vulnerable spruce-fir birds in northern United States

“…2 (continued) continue, and that similar attention would be justified in Olive-sided Flycatcher. Gray Jay, Yellow-bellied Flycatcher, Magnolia Warbler, Blackpoll Warbler, and Evening Grosbeak are all categorized by IUCN as species of ''Least Concern'' and have received minimal conservation attention, though population declines have previously been reported for some of these species (Bonter and Harvey, 2008;King et al, 2008;Sauer et al, 2014;Glennon, 2014). We find evidence for overall declines in all of these species, though propagated errors for Magnolia Warbler and Blackpoll Warbler indicate declines are possibly non-significant.…”

“…That we find at least some evidence for decline in these species suggests further investigations of their statuses in the eastern and Midwestern United States is warranted. For one species, Evening Grosbeak, dramatic modern declines in abundance and range contractions (Bonter and Harvey, 2008;Sauer et al, 2014) follow an equally large range expansion in the late 19th and early 20th centuries (Gillihan and Byers, 2001). More work is needed to determine whether the current trajectory is part of naturally dynamic population processes in this irruptive species, or whether it is indicative of more widespread environmental degradation.…”

Changes in Early Winter Bird Populations in Winnipeg, Manitoba (1978 – 2017)

“…These declining winter numbers appear to be part of a general, continent-wide decline, estimated at 50 per cent between 1988 and 2006; causes are unclear and warrant further study. 25 Prompted by this decline, the Committee on the Status of Endangered Wildlife in Canada assessed the Evening Grosbeak's status and determined it to be a Species of Special Concern. 26…”

Seed and feeder use by birds in the United States and Canada

“…Several scientific studies have examined backyard bird feeding, including research of seed and feeder preferences (Geis , Horn ), feeder placement (Cowie and Simons , Dunn and Hussell ), how bird feeding may influence survival and nutritional demands (Brittingham and Temple , ; Geis and Pomeroy ), disease transmission (Dhondt et al ) and population trends, range expansions, and irruptive migrations of birds at feeders (Hochachka et al , Bonter and Harvey , Robb et al ). In their summary of supplemental feeding studies, Robb et al () called for large‐scale investigations on bird feeding taking place in backyards and noted the limited number of studies that used conditions that emulated how people feed birds.…”