Field Sparrow

Spizella pusilla

Field Sparrows often raise more than one brood per season. Each time, they build a fresh nest. As the season progresses, each new nest is built higher and higher off the ground. While the first spring nests are usually on the ground, later in the season, leaf-litter accumulates and groundcover grows. So the birds build their nests in bushes and trees, where there is more safety from snakes and other predators.

These birds are vulnerable to parasitism by Brown-Headed Cowbirds. Studies in Iowa and Illinois show 50% to  80% of all sparrow nests contained cowbird eggs. In locations with high rates of parasitism, Field Sparrows attacked models of cowbirds placed near their nests. But where little parasitism occurred, the sparrows barely reacted to the models.

Taxonomists recognise two subspecies of Field Sparrow. 

• S. p. pusilla breeds from central Minnesota east through Ontario, New England and south to east Texas and through the Florida panhandle. This group winters from the Great Lakes east to Long Island, and south to the Gulf Coast and central Florida.
• S. p. arenacea breeds in the Great Plains from central Montana and eastern Wyoming east to North Dakota and south to central Texas.

When I first met Field Sparrows, I was visiting friends in Pennsylvania. It was their songs that first caught my attention. There was a ‘bouncing ball’ quality to their songs that reminded me of Black-Chinned or Olive Sparrows. But neither of these species were expected in Pennsylvania. Eventually, I caught sight of them and I was able to sort out the mystery.

In 2023, after my first contact with this species in Pennsylvania, I met more of them a week later in Virginia. As my expedition neared its completion, I found them again in Texas at Kickapoo Caverns.