Article by Kate Redmond
Forest Beach Migratory Preserve was created to be a resting and refueling place for migrating birds as well as a productive habitat for breeding species. It turns out that what’s good for the birds is good for other wildlife, too. A number of rare dragonflies and damselflies have found their way to the preserve, and with more eyes on the place, it’s only a matter of time before others are discovered. Eight of the 42 species on the property list are rare visitors.
Late summer is both a great and a challenging time for dragonfly watching. Great because some of our larger species like darners and saddlebags dominate the air space. Challenging because these dragonflies often fly for a long time without stopping, and when they do rest, they perch vertically, down in the grass or on woody plants. And they’re jumpy; in order to get a picture -- or even a good look at them -- you have to see them before they see you.
Saddlebags are called saddlebags because of the pigmented area on the wings on either side of the abdomen. Red, Black, and Carolina Saddlebags are in the “broadsaddle” group, so-called because their irregularly shaped saddles are wide. Black Saddlebags are common at Forest Beach from mid-summer on; Red Saddlebags are a little less common; and Carolina Saddlebags, rare visitors to Wisconsin from the eastern and southeastern United States, have been spotted at the preserve fairly regularly.
On September 11, 2018, I photographed a fourth saddlebags at the preserve, a Striped Saddlebags (Tramea calverti), and two weeks later, I found another one there, a different individual. Striped Saddlebags, named for the conspicuous stripes on the thorax, is a tropical species. Individuals are considered vagrants or accidentals here, not regular migrants. (Only about 15 species of dragonfly are.) As a result, they’re a most-wanted species among dragonfly enthusiasts in Wisconsin. There are small, resident populations in far South Florida and along the United States-Mexico border, but the dragonflies are more at home through Central and South America, the Galapagos, and the Bahamas. The moral of the story is, “If you see a saddlebags with red saddles, look twice.”
Striped Saddlebags are in the “narrowsaddle” group because the smooth-edged saddles don’t extend very far into their wings. Striped Saddlebags wander farther north than other narrowsaddle saddlebags.
As vagrants, Striped Saddlebags have some big flight years and other years when they stay home, but when they do travel, it’s not uncommon for them to move in small groups. A huge flight occurred in 2010, when an article on the Cape May Bird Observatory’s blog View from the Cape described the area, in New Jersey, as “Swimming in Striped Saddlebags.” Striped Saddlebags also appeared in Michigan, Minnesota, and Ontario. There were widespread sightings in 2012.
The Wisconsin Odonata Survey lists 19 Striped Saddlebags sightings since the first records in 2012, when it was seen in five counties. Of the 19 sightings, 14 are from four southwestern counties along the Mississippi. Along with the individuals seen at Forest Beach in 2018, Striped Saddlebags were recorded Kenosha County in early September and in La Crosse County in late September.
The life cycle of a Striped Saddlebags mirrors that of other saddlebags. Females prefer to deposit eggs in shallow, open, fishless ponds with lots of floating vegetation, and the young dragonflies (naiads) live under water, feeding on any aquatic invertebrates that they can tackle. Mature naiads crawl out of the water, often under cover of darkness in order to avoid predators, rest, and then split the back of their exoskeleton and pull their body out. When their wings are fully extended and hardened, the young dragonflies are ready for flight.
Both male and female Striped Saddlebags were present at Forest Beach in the fall of 2018. Are there naiads waiting for the water to warm in 2019, or would these tropical dragonflies be too sensitive to survive under the ice? Stay tuned.
For more information, see the article “Rare Dragonfly at FBMP” in the Observatory’s May-June 2017 newsletter.