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Lower Colorado River Multi-Species Conservation Program Balancing Resource Use and Conservation

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Wildlife

      Information Article

Quailbush on Conservation Areas Provide Home for Rare MacNeill’s Sootywing Skipper

While most people are familiar with the more well-known threatened or endangered species, not many people are aware of the many rare insects, amphibians, and rodents. The Lower Colorado River Multi-Species Conservation Program (LCR MSCP) is creating habitat for 12 listed and sensitive bird species, but we are also making sure there is enough habitat for a small insect known as the MacNeill’s sootywing skipper.

Skippers are butterflies with large eyes, short antennae (often striped with hooked clubs at the tip), stout bodies, and three pairs of walking legs. Their stockier bodies make them look like a cross between a butterfly and a moth. The MacNeill’s sootywing skipper is small (0.75 to 1.25 inches, 20 to 32 mm) with dark-brown and black mottled wings, and is found only in the Colorado River system. In the image below, note the hooked end of the antennae, which is a telling characteristic of skippers (family Hesperiidae).

Adult sootywing on a heliotrope flower at the Havasu National Wildlife Refuge - Photo by B. Wiesenborn, Reclamation
  Adult sootywing on a heliotrope flower at the Havasu National Wildlife Refuge - Photo by B. Wiesenborn, Reclamation  

Many people catch sight of various species of butterflies when out for a hike or while gardening, but your odds of seeing one of these skippers aren’t great unless you’re hiking near lots of quailbush (Atriplex lentiformis) and are looking carefully. The image below is a good sized quailbush.

Quailbush shrubs growing along the road at Cibola Valley Conservation Area - Photo by B. Wiesenborn, Reclamation
  Quailbush shrubs growing along the road at Cibola Valley Conservation Area - Photo by B. Wiesenborn, Reclamation  

MacNeill’s sootywings lay their eggs on quailbush leaves. Eggs can measure less than 1 mm in diameter. The caterpillars feed only on quailbush. their sizes range by age, but can reach up to 2 mm. Adults require nectar from various plants. If you’re patient, you may see one fluttering about waist-high around patches of quailbush along the riverbank or irrigation ditch.

MacNeill’s sootywing skipper eggs on a quailbush leaf showing size in relation to a person’s hand and a close-up. - Photos by Jeff Hill (top), and S.M. Nelson and R. Wydowski (bottom), Reclamation    Sootywing caterpillar inside its tent of leaves - Photo by S.M. Nelson and R. Wydowski, Reclamation
  MacNeill’s sootywing skipper eggs on a quailbush leaf showing size in relation to a person’s hand and a close-up. - Photos by Jeff Hill (top), and S.M. Nelson and R. Wydowski (bottom), Reclamation   Sootywing caterpillar inside its tent of leaves - Photo by S.M. Nelson and R. Wydowski, Reclamation  

When we monitor birds, we listen for their calls or search for them in the trees. With MacNeill’s sootywing, we also use a few different techniques to discover if they’re using the vegetation found at our sites. We select quailbush at random and visually inspect the leaves for a set amount of time for any eggs or caterpillars, or encounter sootywings flying within or around the shrubs. We’ll also check the surrounding habitat for nectar sources and note the health of the quailbush we’re surveying.

When we monitor birds, we listen for their calls or search for them in the trees. With MacNeill’s sootywing, we also use a few different techniques to find out whether they’re using the vegetation found at our sites. We select quailbush at random and visually inspect the leaves for a set amount of time for any eggs or caterpillars, or encounter sootywings flying within or around the shrubs. We’ll also check the surrounding habitat for nectar sources and note the health of the quailbush we’re surveying.

MacNeill’s sootywing skipper’s may not be found in very many places in the southwest, but we’ve been lucky to have them colonize almost all of our conservation areas that contain quailbush. We’ve surveyed three LCR MSCP conservation areas this spring and found adults and eggs at all of them. In April of 2018, we had four detections during our survey at Pretty Water Conservation Area which was planted with honey mesquite (Prosopis glandulosa) in 2015. The quailbush spread into the restoration area on its own, and the sootywings have followed.

Explore our MacNeill’s sootywing page for more information about this skipper and LCR MSCP’s conservation efforts for this species.

Updated October 25, 2018