Vesper Sparrow by jerryoldenettel
Doing point counts in south eastern PA during the last weeks has left me feeling that some fields birds are a lot more common than many birders suspect. On any given day I have heard multiple Savannah Sparrows, Vesper Sparrows, Grasshopper Sparrows and Horned Larks. I have also come across at least five Blue Grosbeaks in the area this year, including one that is within the safe dates for the PA Breeding Bird Atlas.
These birds all breed across Pennsylvania, mainly around large areas of farm fields. They each prefer slightly different types of habitat. According to Birds of N.A. Online, Vesper Sparrows “prefer dry grass fields, with some shrubs or similar structure, and are found in open habitats, including old fields, shrubsteppe, grasslands, and cultivated crop fields. Savannah Sparrows are more likely to be found in grassy meadows, cultivated fields (especially alfalfa), lightly grazed pastures, and along roadsides.” I usually correlate recently tilled or bare fields with Vesper Sparrow and Horned Lark, horse pastures with Savannah Sparrow and alfalfa and soybean fields with Grasshopper Sparrow.
A drive through farmland should net you all of the sparrow species if you stop frequently and listen from the side of the road.
Blue Grosbeaks are most commonly found in southeastern and south central PA, although I have found several further north, in both Lebanon and Schuylkill Counties. Most of these more northern birds were hanging out around old reclaimed strip mines which resembled the transitional/successional habitat they prefer. As you can see from the map, Blue Grosbeaks are largely concentrated in York and Lancaster Counties in the southeast.
Blue Grosbeaks are much less common in Pennsylvania than the other species I have mentioned but driving and listening in the optimal habitat will often produce one or two birds.
The key to locating all of these species is knowing the songs. The sparrows especially will be found sitting out in the middle of a field, either in vegetation or camouflaged against the earth, so a sharp ear is crucial.