The summer of 2012 has seen one of the greatest northward movements of Dickcissels in recent memory. The irruption stretches from North Dakota eastward through Minnesota, Wisconsin, Michigan, and into eastern Ohio and western Pennsylvania. There are even records from southern portions of Manitoba, Ontario, and western New York. In most regions, Dickcissels are still actively singing and relatively easy to detect. In this article we provide tips for finding Dickcissels near you as well as a brief overview of this year’s irruption. Who knows, maybe your Dickcissel sighting will provide our 100 millionth observation!
The Dickcissel is an iconic species of mid-continent prairie grasslands. While the core breeding range is typically occupied, in some years this species irrupts in large numbers outside the typical breeding range — 2012 is one of those years. The shift northward this summer is likely correlated with climatic conditions and food availability in the core breeding ranges. In particular, drought conditions in the core range have been identified as a key component for previous massive irruptions (Emlen and Wiens 1965, Sealy 1976). However, even within the core range, it appears that Dickcissel nests earlier in the southern portions of the breeding range and then shifts northward, perhaps nesting a second time (Basili et. al. 1997).
Dickcissels nest in a variety of open habitat from native prairie to hayfields and abandoned fields, preferring those with dense cover and prominent song perches. Within the core of its range, Dickcissels are even found along weedy roadsides. In particular, the species prefers areas that have a large percentage of forbs such as alfalfa and clover. They prefer relatively large patches of prairie when available. Nevertheless, the species has adapted to some agricultural landscapes
How you look for Dickcissel depends in large part on where you live. If you live near the core species range, you can search in almost any open area. The farther away you are from the core range, the more you need to key in on ideal habitats. For instance, the only field with multiple individuals in upstate New York this summer is at the Seneca Meadows, an extensive several hundred acre preserve that provides ideal Dickcissel habitat. While hundreds of miles away from the core species range, the field’s large size and mix of forbs, grasses, and prominent song perches were enough to not only attract multiple singing males, but now a female that has been observed carrying nesting material.
Indeed, if grasslands are created anywhere within the wider periphery of the range, then Dickcissel may respond favorably. A good example is Chino Farms, on Maryland’s Eastern Shore, a site renowned for its grassland management. Chino now supports the highest density of breeding Grasshopper Sparrows and Dickcissels in the region. See the Chino Farms bar chart to learn more.
We encourage interested readers to pursue the Birds of North America Online species account. Complimentary access to the Dickcissel account for the BNA will be available from 27 July – 30 September.
Basili, G. D., S. L. Brown, E. J. Finck, D. Reinking, K. L. Steigman, S. A. Temple, and J. L. Zimmerman. 1997. Breeding biology of Dickcissels across their range and over time. Pages 108-151 in Continental-scale ecology and conservation of the Dickcissel. (Basili, G. D., Ed.) author. Ph.D. thesis, Univ. of Wisconsin-Madison, Madison.
Emlen, J. T. and J. A. Wiens. 1965. The Dickcissel in-vasion of 1964 in southern Wisconsin. Passenger Pigeon 27:51-59.
Sealy, S. G. 1976. The 1973 Dickcissel invasion of southern Manitoba. Can. Field-Nat. 90:464-466.