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Return of the Common Green Darner
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For some of us in North America, this winter seemed as if it would never end. Dragonfly-watchers waited with increasing impatience to see what is for many, especially those who live in more northern climes, the first dragonfly of the year on the wing--Common Green Darners (Anax junius) returning north in the spring to mate and breed.
The best clue that these adults are returning migrants is that mature adults are seen in spring when the local weather conditions have not yet been warm enough to allow overwintering nymphs, which enter a hibernation-like state called diapause, to warm up, begin feeding, complete their development and emerge as adults. That 1st sighting of the year may be mature adult males with their unmistakable bright green thorax and long blue abdomen making ceaseless patrol flights across a pond in Florida in January, or noting a few tandem pairs laying eggs (ovipositing) at the edge of a lake in Ontario at the end of April--or even later, depending on the weather.
Presumably the offspring of migrants that headed south the previous fall, these returning migrants flying north are surrounded by an invisible cloud of questions, such as: Where did their parents come from? In what southern wetland did these returning migrants develop as nymphs? What environmental triggers made them start their return north? What makes some migrants move past suitable habitat in northern Mexico and the southern US until they've reached ponds in New York, Michigan and Canada? Will all of the offspring of migrants develop rapidly enough through the summer to emerge as adults that will themselves migrate south in the fall, or will some pass the winter as resident overwintering nymphs to emerge the following spring?
The answers to these questions won't come quickly, but with the help of dedicated volunteers, we will be able to illuminate some of these mysteries. MDP volunteers have added a fantastic number of records to the MDP database, and we are already seeing some differences in return times for Common Green Darners for the late, snowy spring of 2013 compared with last year's unexpectedly hot weather. There are over 40 new records in the MDP database for Common Green Darners in 2013, with the earliest seen on January 12 in Brandon, Florida, and the most recent on May 21 in New York State. The 1st records of the year for Common Green Darner in Canada came in on April 15 from Ontario.
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Map of 2013 Common Green Darner sightings. Click on the map to view info on each sighting.
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Spring 2013 isn't over yet, and reports of other migratory species are starting to trickle in, including Black Saddlebags (May 14, Minnesota), Variegated Meadowhawk (April 29, Minnesota), Wandering Glider (May 7, Indiana), and Spot-winged Glider (May 17, Texas). With regular reporting across multiple years, we will be able to examine patterns of migrant return in conjunction with changing weather conditions. Let's keep those records coming!
Thank you to our citizen scientist
volunteers for submitting records!
MDP's Mission
The Migratory Dragonfly Partnership is composed of dragonfly experts, nongovernmental programs, academic institutions, and federal agencies from the U.S., Mexico, and Canada. Together, we are combining research, citizen science, and education and outreach to better understand North America's migrating dragonflies and promote conservation of their wetland habitat.
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Check out our events page for information about the upcoming Migratory Dragonfly Short Course in Vermont. Two final courses in 2013 are slated for the fall--one on the California coast and the other at the Long Point Bird Observatory in Ontario. Check back to the events page for registration details.
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The MDP produced this printable online adult dragonfly ID guide to assist project participants in identifying our five focal species.
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Don't see your observation on our map? Sign up to contribute to MDP projects! Collect and submit seasonal information about your dragonfly observations. |
ID GUIDE: EXUVIAE
Observations of exuviae (cast-off skins of dragonfly nymphs) at ponds will help us understand local emergence timing of resident dragonfly populations. The MDP is developing an ID guide to exuviae that will assist participants in field collection and identification.
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PHOTO CREDITS
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Banner:
Common Green Darner (Anax junius)
by John Abbott.
In-text:
2013 Common Green Darner reports.
ArcGIS.com online map by Michele Blackburn.
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