South Dakota Nature Notes
It's a fine time to see butterflies and birds in South Dakota.
Summer is well-underway in July. This is a month when many birds have completed their spring nesting and are busy raising their young, although some late-nesters are still laying eggs. Long-distance travelers such as shorebirds begin passing through South Dakota on their south-bound migration in July. The month also brings new flowers to the state’s landscape, notably coneflowers and other showy prairie plants that begin blooming in June and become more numerous as summer progresses. The new flowers attract insects seeking nectar and locations to lay their eggs on the host plants that provide food for hatching larvae—this is a good time to look for butterflies in South Dakota’s grasslands.
One of those butterflies is the regal fritillary, found in tallgrass and mixed-grass prairies and only for a few months every year. This butterfly’s flight period begins in late-June when larvae from the previous year have completed their metamorphosis from caterpillar to adult. The larvae feed on the leaves of violets, which are most lush in the spring then senesce during the heat of summer.
By the time that warm weather has arrived, the caterpillars have been transformed into conspicuous butterflies, with orange wings up to four inches across flecked with black and white spots. These breeding adults feed on nectar from plants like milkweed and thistle until they lay their eggs in August on the violets that will feed the next generation. The eggs hatch in the fall and the tiny new larvae immediately crawl into the leaf litter where they remain dormant until spring when the violets are again at their best. The regal fritillary has become less common as the prairies it needs become fewer—in South Dakota, a good location to look for them is TNC’s Samuel H. Ordway Jr. Memorial Preserve.
The Nature Conservancy’s Ordway preserve is prairie pothole country – there are more than 400 ponds and wetlands on its 7800 acres that are good duck habitat. Thousands of waterfowl nest here and it’s also home to grebes, rails, herons and other water birds.
East of Ordway, and just north of Aberdeen is another good destination for birders in July: Sand Lake National Wildlife Refuge. More than 266 species of birds can be found in the refuge’s 21,000+ acres of potholes and prairies. The world’s largest nesting colony of Franklin’s gulls (more than 100,000 pairs) is at Sand Lake, making it a good place to watch these small gulls with black heads and red bills that build floating nests in the wetlands. The chicks hatch in June and often are fledged by early July. Sand Lake is also well-known for the huge numbers of snow geese that visit the refuge during spring and fall migrations.