Irruption Alert: Waves of Evening Grosbeaks and Purple Finches Are Streaming Southward:
By Ryan F. Mandelbaum —
Purple finches and Evening Grosbeaks have been trickling southward for the past few weeks. But over the last week, that trickle turned into a full-on downpour, with large numbers appearing at feeders and migration hotspots across eastern North America.
This year’s Winter Finch Forecast predicted that these two species would irrupt southward, following the large spruce budworm outbreak and poor mast crop in much of the eastern boreal. The past few days signaled the start of a large-scale irruption event.
Morning flight counters have regularly observed both species flying past the Observatoire d’Oiseaux de Tadoussac in Quebec since the count season started in late August. Daily purple finch numbers regularly climbed into the hundreds at Hawk Ridge in northeastern Minnesota in September, with smaller numbers outside of forested areas, throughout the Great Lakes and coastal northeast.
The movement has continued to ramp up. Cape May has reported at least 85 purple finches every day from October 19 to October 26—Cape May’s purple finch count this year has already surpassed the purple finch movement in October 2020 by a couple hundred birds, and there’s still four days left to the month. Purple finch numbers continue to increase in the northeast, and birds are creeping southward along the East Coast, as far south as South Carolina. At one site in southern Ontario along Lake Huron, an anonymous birder tallied at least 1600 Purple Finches flying by. Expect Purple Finches to continue to move southward into the Gulf Coast States over the next weeks to months.
Evening grosbeak movements, too, are beginning to mirror the predictions of this year’s Winter Finch Forecast. Birders have already spotted these charismatic finches throughout southern and Maritime Canada, New York, and New England—as far south as the Philadelphia and Chicago suburbs, and just yesterday October 25th Cape May, New Jersey had their first of the season. The conditions are looking similar to 2020, when the last week of October brought a large-scale push of Evening Grosbeaks across Eastern North America. There’s a good chance Evening Grosbeaks move into the mountains of the Virginias and possibly further south over the coming weeks and months.
Evening Grosbeaks and Purple Finches are both spruce budworm eaters, and a widespread outbreak of spruce budworm in the boreal forest is likely leading to short-term population increases. However, both birds are experiencing long-term declines, especially the Evening Grosbeak. Evening Grosbeak populations have declined by 92% in the past 50 years, the steepest decline of any landbird in the continental US or Canada, according to the Partners in Flight 2016 Landbird Conservation Plan. The Finch Research Network has teamed up with the Pennsylvania Natural Heritage Program and Powdermill Avian Research Center to track the movements of these birds to better understand their ecology and decline. If you think you have something to add (we are looking for enthusiasts, conservationists, and social scientists and more) to our International Evening Grosbeak Road to Recovery Working Group, and want to be part the team, please feel free to email email@example.com
Keep your feeders clean and stocked and keep birding—this fall is shaping up to be a great time to observe these two species in large numbers south of the boreal forest.
Cover photo credit Matthew Young
The Finch Research Network (FiRN) is a nonprofit, and has been granted 501c3 status. FiRN is committed to researching and protecting these birds and threatened finch species like the Evening Grosbeak, a species that has declined 92% since 1970. We are fundraising around an Evening Grosbeak Road to Recovery project in addition to a student research project, so please think about supporting our efforts and making a small donation at the donate link below.
Another way to help support the cause can be found at this link to the Evening Grosbeak Road to Recovery apparel: Grosbeaks Road to Recovery Apparel – FINCH RESEARCH NETWORK (finchnetwork.org)