Bowdoin National Wildlife Refuge (NWR) is home to many species of wildlife but some of the most interesting are the grassland songbirds. People come from all over the United States and Canada to see birds such as the Baird’s sparrow and Sprague’s pipit.
Both species inhabit native grasslands on their breeding and wintering grounds and their populations have declined significantly due to the loss of native prairie. Because of this decline, a study was done from 1994 through 2007 at Bowdoin NWR to help biologists and wildlife managers understand more about these and other grassland bird species.
Sprague’s pipits arrive at Bowdoin by the end of April and the males can be heard singing while they circle high over their territories. Baird’s sparrows, one of the last grassland birds to arrive each spring, are usually present by the second week in May and sing their distinctive song while perched on grass clumps or shrubs.
Males of both species establish territories by singing, and part of the study at Bowdoin involved mapping territories to determine how many males were present in a given area and the size of their territories. Because pipits usually sing only while flying, their territories can be difficult to map. Baird’s sparrow territories are much easier. Since Baird’s sparrows tend to sing from perches within their own territories they can be flushed from perch to perch and the boundaries quickly mapped. Territory sizes are approximately 3 - 4 acres for pipits and 2.5 acres for Baird’s sparrows.
Female pipits and sparrows arrive after the males and soon begin choosing mates and building nests. Both species build nests by scraping out a dirt cup on the ground and lining it with grass. Baird’s sparrows have open nests which are usually found in dense grass in shallow drainages and swales while Sprague’s pipits have larger nests which are covered by a dome of woven grass.
Both species are extremely secretive and approach the nest by walking through the grass. At Bowdoin, most nests are found with a rope drag method in which two people drag a 35 meter rope across the prairie. The rope has a fringe of cans attached which creates noise and helps flush the females from their nests. Once the nests are found they are checked every three days until the nest becomes inactive due to fledging of the young or predation. This information helps biologists determine the overall nesting success for each species.
Both species lay three to five eggs and incubate for 11 to 13 days. Once the nestlings hatch they remain in the nest for eight to ten days while the female cares for and feeds them. If the nest is successful, the young leave the nest several days before they can fly and are cared for by both parents.
Biologists at Bowdoin NWR have been banding nestlings since 1996 and adults since 1998 in order to determine if the same birds return each year. Each bird receives a numbered metal band and a colored band on the left leg and two colored bands on the right leg. The colored bands are in a specific combination which enables an observer to identify an individual and to know exactly when and where that bird was banded.
All species bands have low returns, which is common with grassland songbirds, suggesting that both species rarely return to the same breeding grounds year after year and, instead, choose areas depending on weather and grassland conditions.
Results indicate that the Baird’s sparrow population seems to have stabilized while Sprague’s pipits continue to decline. Native grasslands at Bowdoin NWR and other places in Phillips County are becoming increasingly important for these species as well as for anyone wishing to see or hear these secretive grassland birds.