Thursday, March 19, 2015

Hawk Watchers Contribute Valuable Data to Another Successful Year of Dragonfly Migration Monitoring

Participating hawk watch sites in 2013 and 2014.
In 2013, HMANA partnered with the Migratory Dragonfly Partnership (MDP), a group dedicated to the long-term study of dragonfly migration in North America, to for­mally incorporate daily dragonfly observations and counts into the fall monitoring protocols of participating hawk watch sites. 

HMANA partnered with MDP again in 2014 to continue monitoring efforts and help increase our un­derstanding of dragonfly migration. After just two years, some interesting trends are coming to light. Thank you to the Xerces Society for analyzing the data and summarizing the findings. You can read the full 2013 and 2014 reports online at http://www.hmana.org/migratory-dragonfly-partnership/.

By the end of the 2014 migration season, over 1,300 individual species records had been collected from 40 hawk watch monitors at 19 participating observatories. 

Number of dragonflies counted flying past 19 hawk watch sites 
in eastern North America in 2013 and 2014.
Fall migration in eastern North America begins near the end of August and can con­tinue into October, although numbers are usu­ally highest in September while migration on the west coast begins about two weeks later. Within that span, some days see enormous spikes in the number of passing dragonflies while others have no activity at all. Migration intensity may vary from year to year; two pulses in 2014 occurred early in Sep­tember, but peak numbers were seen later in 2013.

In 2014, Lighthouse Point in CT experienced the highest one-day migration pulse of almost 6,000 dragonflies on 7 September, and Hawk Ridge, MN and Illinois Beach, IL both witnessed peak dragonfly numbers (>6000) on 2 September. The two Midwestern strongholds of Hawk Ridge and Illinois Beach were also champi­ons in overall reporting, with 151 and 95 observations submitted, re­spectively. Because dragonflies skirt coastlines, preferring not to fly out over open water, raptor monitors at these Great Lakes sites are ide­ally placed to witness large groups of migrants funneling past observa­tion sites.

Attention Spring Sites!
Based on the success of this partnership, HMANA is excited to continue participating in the MDP in 2015.We are looking to broaden efforts at hawk watch sites, not only throughout
western reaches of North America, but also gathering information about northward
spring migration for dragonflies. How much you or your spring site would like to be involved is completely up to you.

If you’re interested in participating, please contact Julie Brown (brown@hmana.org) for more details.  For more information, monitoring guidelines and protocol, please  visit http://www.hmana.org/migratory-dragonfly-partnership/.

And thank you to all participating hawk watch sites and individuals for making the Migration Dragonfly Partnership such a success!







2 comments:

  1. Ah, but at some hawk-count sites, it's simply impossible to count migratory dragonflies and do anything -- and I do mean "anything" -- else. In my two falls at Smith Point, TX, there were numerous times at which 6000 dragonflies were visible at once. Since I was being paid (if we can use that term loosely) to count migrant raptors, there was just no way, despite my interest, to count dragons.

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  2. Tony: We understand and that is just the way it has to be. I think the Xerces people would still be interested in an estimate and the species, if identifiable, as they are just getting started with their own migration monitoring. We will help them as we can, but for HMANA, the raptors take precedence.

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