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Return rates of breeding Henslow's Sparrows on mowed versus unmowed areas on a reclaimed surface mine.

Article Excerpt
Populations of Henslow's Sparrows (Ammodramus henslowii) have steadily declined in the glaciated portions of Ohio (Swanson 1996, Sauer et al. 2005), but have increased in the southeastern, unglaciated counties where reclaimed surface mines are common (Peterjohn and Rice 1991, Sauer et al. 2005). Recent studies have shown that nesting success of Henslow's Sparrows on reclaimed surface mines is comparable to that on a variety of unmined lands (Monroe and Ritchison 2005, Galligan et al. 2006).

An important component that should be considered in weighing the long-term usefulness of reclaimed surface mines for Henslow's Sparrows and other grassland birds is the rate at which individuals return to previous breeding and nesting areas. Nest-site fidelity, the propensity of individuals to return to breed at a previous breeding site, has been documented in a variety of bird species (Gavin and Bollinger 1988, Bollinger and Gavin 1989, Porneluzi 2003). Fidelity in grassland birds has been positively associated with hatching and/ or fledging success of individuals during the previous year (Gavin and Bollinger 1988). Relatively few studies have focused on nest-site fidelity in grassland birds, and even fewer have examined return rates (marked individuals returning to previous nest sites) of grassland birds on reclaimed surface mines. We found two studies that addressed return rates of Henslow's Sparrows on a reclaimed surface mine. Skipper (1998) reported that five of 27 (18.5%) color-banded male Henslow's Sparrows and zero of seven color-banded females returned to nest in the same location as in the previous year in Maryland. Monroe and Ritchison (2005) reported that two of nine (22%) marked male Henslow's Sparrows returned to the same location on one study site and that two of 18 (11%) males returned to a second study site, both in Kentucky.

Reclaimed surface mines in some cases provide suitable nesting habitat for a variety of grassland birds. One of the next steps is to consider extrinsic factors that influence grassland habitat structure (e.g., mowing, hay-cropping, burning, and grazing) by examining reproductive success and/or return rates to previous breeding sites. Numerous studies have shown that mowing and hay-cropping, particularly between May and August, adversely affect reproductive success of several grassland bird species in the midwest and northeastern United States (Bollinger et al. 1990; Frawley and Best 1991; Herkert 1994a, b; Swanson 1996; Ingold 2002). Few studies, particularly on reclaimed surface...