A Lesser-Known Irruption Is Occurring in the West

By Ryan F. Mandelbaum:

While finch fans are experiencing a banner year for boreal birds in the Eastern United States, birders in the West have their own finches on the move.

Lawrence’s Goldfinches are the west’s finch nomads. These gray-bodied, black-faced birds (and talented mimics) only breed in the arid woods and foothills that California and Baja California are famous for—but show almost no loyalty to any single spot, breeding in a site one year only to disappear the next. Their reliance on native plant seeds like fiddleneck in the summer and chamise in the winter make their population dynamics a lot like the finches in the East; these goldfinches “irrupt” beyond the core of their range and into Arizona during years following a successful breeding season.

Western finch fans will be able to get a taste of 2020’s finch flight, as Lawrence’s Goldfinches appear to be on the move. While October-November 2019 saw only a few reports of these finches beyond their preferred habitats in California, this year, they’ve shown up in San Francisco, throughout Arizona, deep into Baja California, and as far east as Texas’ Franklin Mountains State Park, just north of El Paso. 

If you hope to catch a glimpse of these birds, your best shot is to look in early morning or late afternoon for water near weedy fields with their favorite seeds, especially chamise but also mistletoe, coffeeberry, pigweed, and inkweed.

Photo Credits Liron Gertsman

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