Evening Grosbeak in WI in winter

Evening Grosbeak - Wikimedia Commons

One of the favorite winter birds for many people, the numbers of Evening Grosbeaks in Wisconsin in winter are most assuredly not what they used to be! Christmas Bird Count results reported to NAS over a 40-year period are graphed at left. Although this analysis is a bit dated already, it offers some facts and explanations for this decline. Interactions with spruce budworm infestations are described here. A more recent - and much more technical paper, with some possible        (and related)  conclusions can be found here.