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Fishing with a Little Help from our Friends AC/DC

A smallmouth bass with bright markings.

A smallmouth bass with bright markings.

When scientists want to sample a fish population, they don’t rely on a rod and bait. Under certain circumstances they will use nets, and often in streams and rivers they will use electrofishing. HRWC got the chance to do a little electrofishing this past week.

To electrofish in a shallow river, a gasoline generator is put into a light boat. The generator is hooked to two long poles, called booms, that are placed into the water and create an electric field between themselves and the bottom of the boat.  The electric field does not kill fish but temporarily stuns those that get within a few feet of the booms.  While stunned, workers with nets scoop up the fish and put them in tubs filled with water. The fish are then identified and sorted, and eventually released back to the river safe and sound.

Last Wednesday, several HRWC staff went out with our partners from Environmental Consulting Technology (ECT) to sample the Huron River along Riverside Park in Ypsilanti.  We saw plenty of fish in this stretch, including several big smallmouth bass and one big walleye.  While we still need to officially work up the results, our initial observations were that the fish are indeed using the cover and deep water habitat that HRWC  installed two years ago, and the fish were bigger and more numerous than when we electrofished the same reach before the habitat was installed.

We will report back when the final results are in. Until then, enjoy some fish pictures!

pulling a eletrofishing barge at River side Park, Ypsi

ECT staff pull an eletrofishing barge at Riverside Park, Ypsilanti

watch for those teeth!

We caught a walleye at Riverside Park. Watch out for those teeth!

The fish are measured before we let them go.

The fish are measured before we let them go.

Make a Difference… Be a Scientist on Earth Day

Join a team of kids, teens, adults, and retirees during the River Roundup as you explore creeks and rivers.

Join a team of kids, teens, adults, and retirees during the River Roundup as you explore creeks and rivers.

Earth Day falls on April 22 this year, and not accidentally, so does HRWC’s spring River Roundup.  Perhaps the idea of Earth Day may strike you as a little disheartening this year, in our current political climate of science and environmental budget cuts, and widespread doubt in scientific data.  Are we making a difference at all?  Or is our country reverting back to an era of rivers catching on fire?  What is so disheartening to me personally is not a looming Federal budget that will remove funding for the Great Lakes and environmental regulation (though that is terrible, don’t get me wrong, but I’m not surprised by this), but to see so many people who agree with this course of action. Still, there is room for hope in our future, and that hopes lies in you—the many people who want clean water and clean land and who stand strong with HRWC to work for it.

Consider volunteering with us. Every participant makes an immediate difference at our local level.  HRWC volunteers collect scientific data in southeast Michigan, primarily in Oakland, Livingston, Washtenaw, and Wayne Counties. For the upcoming River Roundup on Earth Day, volunteers will be looking for aquatic insects that tell us about the health of the Huron River and its tributaries, and ultimately about the health of all the land that drains into the Huron.  This information gives HRWC the knowledge to conduct effective river management projects and the authority to speak  intelligently on water quality issues with local, state, and federal government, landowners, and  other decision-makers.

And in the process of collecting scientific data, HRWC volunteers are learning and teaching others.  It is always so exciting to see the adult HRWC volunteers interacting and teaching children, teens, and college students about river systems, insects, and the environment.  And in as many cases, to see the kids teaching the adults! This is the type of education that will create the long term cultural change needed in our country.

Make a difference locally by acting now to help HRWC collect scientific information that informs our management decisions and local policies; change the future by teaching the younger generation in the process. The River Roundup is on Earth Day, April 22.  Learn more about the River Roundup and register at http://www.hrwc.org/volunteer/roundup/

River Roundup Results Reviewed: October 2016

Credit: Ellen Rambo

Picking a huge log is always great for group bonding. Seriously! Credit: Ellen Rambo

Aquatic insect sampling on the Huron River and its creeks

Thanks to 154 volunteers who contributed approximately 600 volunteer hours, the October 2016 River Roundup was a great success!  As always, HRWC 100% guarantees good weather for its volunteer events or your money back.  We were once again able to fulfill that promise!

It was a very full house here in the HRWC conference rooms before the 18 teams split up and traveled to 36 different creek and river locations across the Huron River Watershed to assess the aquatic benthic macroinvertebrate community.  This study is one of the most effective ways that HRWC has to understand how the water quality of the river and creeks may be changing. From the data collected at this semi-annual event, we are able to keep abreast of the health of our waterways throughout the watershed. You can see a summary below, or detailed results in the October 10 River Roundup Report.

Site Conditions as of October 10, 2016

Site Conditions as of October 10, 2016

 Current Watershed Health

Status

HRWC gives a rating to each site that we monitor (Excellent, Good, Fair, or Poor). The graph above shows this breakdown for the 61 locations that HRWC considers representative for the watershed. The detailed River Roundup report gives the site condition for each location.

Trends

Overall, the health of the watershed as judged by our macroinvertebrate sampling is holding steady, though there are particular areas getting worse or better.  30 sites have had no statistically significant changes over time, and 4 sites are too new to make this judgment.

Fifteen sites are declining, and these include locations on Norton Creek, Horseshoe Creek, and Honey Creek (Washtenaw Co).  Ten of the declining sites are in Livingston County, 3 are in Washtenaw, 1 is in Oakland, and 1 is in Wayne.

Twelve sites are significantly improving.  Eleven of the improving sites are in Washtenaw County, including locations on Mill Creek, Malletts Creek, Fleming Creek, and the Huron River. One site is improving in Livingston County (Mann Creek at Van Amberg Road), and 1 site is improving in Wayne County (Woods Creek at the Lower Huron Metropark).

Highlight

Mark Schaller searches for bugs in the Huron River near Ypsilanti. Credit: Ellen Rambo

Mark Schaller searches for bugs in the Huron River near Ypsilanti. Credit: Ellen Rambo

There were a lot of highly diverse samples collected this season.  The team at Pettibone Creek: Commerce Road in Milford collected the most diverse sample ever taken at the site (sampling started here in 2001).

Two sites on South Ore Creek were diverse enough to pull these creeks out of a statistically significant decline and into the “declining but not significantly so” range.

The sample taken at Davis Creek off of Silver Road was the best sample taken in about 8 years.

Lowlight

For some teams, sampling conditions were difficult.  The Huron River was running fast and deep after the area received heavy rain just a few days before the event started. The sample taken at the Huron River at Zeeb Road was particularly bad and far outside the range of normal variation.  Based on the volunteer’s feedback and the difficulty of sampling the river, this sample was marked as an outlier and will not be included in the long-term record for the site.

What’s next?

Want to learn more about the data that HRWC collected this past year? On January 19th at 6 pm at our office on 1100 N. Main Street, HRWC staff will present results and interpretation for all of the field projects conducted within the past year. Good indoor weather guaranteed!

Do you consider yourself a Michigander, or aspire to be one? Then you should brave the cold and join the Winter Stonefly Search on January 21.  It is like the River Roundup, only much snowier and usually colder. Good weather guaranteed or your money back… but of course these events are always free!  You can register for the event here.

This giant water bug makes a run for freedom! Credit: Aiman Shahpurwala

This giant water bug makes a run for freedom!
Credit: Aiman Shahpurwala

Searching for European Water Clover

Graham Battersby, HRWC volunteer, surveyed Barton Pond for water clover in 2015. credit: G. Battersby

Graham Battersby, HRWC volunteer, surveyed Barton Pond for water clover in 2015. credit: G. Battersby

As mentioned in the Summer 2016 HRWC newsletter, both Barton and Argo Pond on the Huron River are home to a new exotic aquatic plant, the European Water-Clover (Marsilea quadrifolia). In 2015, Michigan DEQ alerted HRWC that this plant was only in two places in the state, Barton/Argo Ponds and a location in the Clinton River Watershed.  However, they were unaware of  how widespread this plant was in our system.  In 2015, HRWC volunteers searched those ponds and found many patches of the plant and reported their location back to DEQ.

The scientific community at large is generally ignorant about the European Water Clover; people do not know how it spreads, to what extent it can out-compete nearby native plants, and how it might change the ecology of the system.  This is often an issue with new exotic species; scientists often don’t know how damaging something will be until it becomes a problem. It is important to get a handle on these new plants, though, because you can’t predict when the next Phragmites will arrive- a plant that spreads very rapidly and changes its ecosystem. And any control methods have to be done very carefully, as so many plants (such as Eurasian Water Milfoil) can actually spread faster and further if they are carelessly ripped out.

This past spring, HRWC put a monitoring plan together with DEQ.  To determine when the plant first emerged, HRWC visited two known problem areas weekly in Argo and Barton Ponds through the late spring and early summer.  The water clover was first detected in early June.

steen kayak water clover

Not at bad day at the office. Paul Steen searches for water clover on the Huron River. credit: G. Battersby

To determine possible spread of the water clover, HRWC and DEQ waited until early August of this year, when the plant would be at its full summer growth, and surveyed upstream of Barton Pond, from Delhi Metropark to the Maple Street Bridge.  Thankfully, that section of the Huron River was clear of the plant.  It does seems that the plant strongly prefers very slow water, and the Huron upstream of Barton generally flows at a moderate to rapid rate.

HRWC is planning additional monitoring downstream, through Gallup Park and Superior Pond, which contains more promising habitat for the plant. DEQ is also planning to try out some control methods, conducting both herbicide treatments in a greenhouse and an exclusion method using a mat that covers the plants in the river.

HRWC will continue to watch this exotic plant and report out as more is learned about European Water Clover in the Huron River system.

Follow the Huron Water Trail to adventure…

Fish, paddle, or play at the Bell Road access point

Located slightly north of the intersection of Huron River Drive and North Territorial, this Huron River access site has it all. The river is absolutely lovely here, with lush forested riparian zones, shallow rocky riffles, deep pools, and a path that stretches upstream and downstream along the river.

The parking area is a little confusing. It is at the end of a dead-end road and there is no parking lot and you can’t see the river.  The site is officially a DNR access point though, so parking is allowed here.  Park at the end of the road and walk fifty yards down the path to get to the river.

I now call this location my “swimming hole” and regularly take my six year old son to play in the river, tube up and down the small rapids, throw rocks, and jump off logs and the small rock dam. It is also on a section of the river known for a superb smallmouth bass population (please catch and release!), and many people use it as a starting point for paddling instead of the busier Hudson-Mills Metropark slightly downstream.

An early spring shot of the Huron River at Bell Road.

Stonefly Search: Lots of searching, not so many stoneflies

January 23rd was a beautiful day for the annual Stonefly event.  The weather hovered around 30 degrees and the sun shone nicely throughout the volunteers’ time outside.  They were searching for stoneflies, an insect that only lives in the healthiest creeks and rivers. The absence and presence of stoneflies, and the trends in their population that we see after visiting a location over and over again, give us clues as to how the water is changing over time.

stonefly_jackie Richards

The beautiful Fleming Creek at Parker Mill County Park. credit: Jackie Richards

Strange Weather

Unfortunately for the purposes of data analysis and clear-cut answers, stoneflies are affected by more than water quality, however.  Strange weather can also play havok on their ecosystems, causing populations to drop off. Our volunteers came back with very low amounts of stoneflies this year, and while we can’t be certain, it is possible that our variable Michigan weather is to blame.  You may recall that December was unseasonably warm in 2015, and wonder how that might affect the insects.   However, in this case, it wasn’t a warm December that hurt the stoneflies, but instead February 2015, a month that was extremely cold.  In fact, it was one of the coldest February’s on record.  When streams and rivers are covered by thick ice, oxygen levels decline, which is bad for all aquatic life but particularly bad for stoneflies, who have high oxygen requirements.  Also, February and early March are when winter stonefly adults are emerging, mating, and depositing eggs; all activities hampered by extreme cold and ice cover. In summary, the cold 2015 winter had direct consequences for the stoneflies in 2016.

Volunteers did not find stoneflies at many places this year, but five locations in particular that did not have stoneflies were noteworthy as all of them have a long (10+ years) history of always holding stoneflies.  In addition, all of these locations have great insect populations at our other events and there are no indications of water quality issues, further strengthening the argument that this year was a weather-related population decline. These five locations were three places on the main branch of the Huron (White Lake, Zeeb, and Bell Roads), Arms Creek at Walsh Road, and Boyden Creek at Delhi Road. Many other locations had reduced numbers or family counts.

Those interested in all results can see them here: PDF report.

A spud is an essential tool for any stonefly searcher. credit: Francis Connolly

A spud is an essential ice-smashing tool for any stonefly searcher. credit: Francis Connolly

Other Results:

Prior to the event, I laid out several examples of things that we would watch for this year:

Davis Creek at Pontiac Trail:  Stoneflies have been dropping off here for the past decade.  Volunteers did come back with stoneflies this year, though not the winter stoneflies but rather a family that is more widely available.  Still, this is good news.

Honey Creek at Wagner Road: Stoneflies were missing here in 2014 for the first time, and unfortunately volunteers did not find them this year either.

Woods Creek at Lower Huron Metropark: Just like Honey Creek at Wagner Road, stoneflies were not found here for the second year in a row.

Insect populations are resilient and can bounce back with good water quality and suitable weather conditions.  While this year was disappointing, the mild winter we are experiencing right now may result in a bumper crop in 2017. Come next January, HRWC and its volunteers will be ready to check it out!

 

Answering Questions with Bugs: The Stonefly Search

The slender winter stonefly, Capniidae.  Credit: www.troutnut.com

The slender winter stonefly, Family Capniidae. Credit: www.troutnut.com

It is January, which means that one of HRWC’s favorite events, the Stonefly Search, is right around the corner.

Stoneflies are interesting because they are the most pollution intolerant group of aquatic insects that we have in Michigan.  They can only thrive in the cleanest water with high levels of dissolved oxygen.  When they are found at a location it is a confirmation of high water quality, and when they disappear from a stream it is a warning sign that water quality has degraded.

It might seem strange to many that we hunt for stoneflies in the winter.  This is because two of the stonefly families, the Capniidae and the Taeniopterygidae, change from aquatic nymphs to terrestrial adults in the late winter and early spring.  This means that we can’t find them during the normal April River Roundup, and so we have to look for them earlier in the year!

The Stonefly Search always produces interesting results.  Let’s take a look at some of the findings in recent years.

Stonefly Successes!

Reported in 2013: Four sites had the best stonefly samples that had ever been seen at those locations: Chilson Creek at Chilson Road, Fleming Creek at Galpin Road, the Huron River at Flat Rock, and Woodruff Creek at Buno Road.  At each of these sites, the stoneflies normally found at the location were there, but also new stonefly families were found that had never been seen there before! A greater diversity of stoneflies indicates greater stream health.  These are promising results and hopefully it will continue into longer term trends.

Reported in 2011: Since 2007 and up through last year, our volunteers have found 4 families of stoneflies in Mann Creek. This includes 2 stonefly families that can be found in creeks year round (Perlidae & Perlodidae), and the 2 stonefly families that are only found in the winter (Capniidae & Taeniopterygidae). Even in the Huron’s healthiest streams, it is unusual to find more than 2 families of stoneflies during the Stonefly Search.  So, Mann Creek is special indeed. Mann Creek flows through a residential neighborhood- but one really interesting thing about Mann Creek is that there is a very wide natural riparian zone surrounding the creek.  This riparian area provides habitat and food for stoneflies as branches and leaves fall into the creek. To see Mann Creek and its impressive riparian zone, click here.

Stonefly Failures!

Stonefly Search: Kid friendly since 1995. credit: Peter Jung

Stonefly Search: Kid friendly since 1995. credit: Peter Jung

Reported in 2015: Davis Creek at Pontiac Trail (near South Lyon) is a location where the stonefly population has dropped over time. This change is concerning because it happened slowly over the last ten years and our spring and fall samples show a very similar pattern.  In the early 2000s we regularly found one or two stonefly families at the creek, but they started to drop off and now have not been found since 2009.

Reported in 2015:  The team searching for stoneflies in Honey Creek at Wagner Road (Ann Arbor) were unable to find stoneflies. This site has been sampled 14 times since 1995, and this is the first time that stoneflies could not be found. This is a site with lots of turbulent highly oxygenated water and should be a great place for stoneflies. Taken in isolation, the absence of the stoneflies at Wagner Road would not be concerning given that this is a single sample.  However, two upstream Honey Creek Adopt-a-Stream sites used to have stoneflies but haven’t in years.  Stoneflies haven’t been seen in Honey Creek at Jackson Road since 2008; they haven’t been at Honey Creek at Pratt Road since 2003. All of the pieces combined indicates that the overall quality of Honey Creek is degrading over the last decade.

Reported in 2013: The team searching for stoneflies in Woods Creek in Belleville came back disappointed.  Wood’s Creek at the Lower Huron Metropark has been sampled 12 times since 1997, and this is the first time that stoneflies could not be found. The problem likely comes from the thick ice and difficult conditions rather than pollution or disturbed stream habitat, but we will keep an eye on Wood’s Creek next year.

What will we find in 2016?

Will Mann Creek continue to reign as the king of Huron River stoneflies?  Will we find stoneflies where they have never been before?

Will we find stoneflies this year at Davis, Honey, and Woods Creek, or has the water quality there continued to decline?

We will see you on January 23 and we will answer these questions together!

Click here for registration and more information.

What will this Search find this year? credit: Dan Myer

What will HRWC volunteers find this year? credit: Dan Myer

Winter Stoneflies in Arctic Michigan

A Celebration of a Very Cold Event

by Dr.David Wilson

We don our coats and boots, go forth to break the ice

In frigid, frosty weather that no one could say is nice

We flounder through the streams in search of a great prize

Taeniopterids and Capniids, precious winter stoneflies

 

Winter stones are quite the thing

Though one surely might be wondering

How these tiny creatures could ever be so bold

As to live and thrive in this bitter winter cold

 

Paul tells us that in winter these critters really thrive

Cold water holds the oxygen to keep them all alive

And winter is helpful in another major way

The cold keeps fierce predators so very far away

 

Quite sensitive to any water pollution,

Winter stones provide a quick solution

If we find ‘em we can be sure

That the stream is sweet and pure

 

The critters are small and rather dark

In this frigid weather they have a lark

Scamper about in the ice and snow

There’s no other place for them to go

 

To ID them here’s what you do

Look for wingpads four and cerci two

Along the flanks no gills are found

And on each leg two claws astound

 

The ice is thick, the water chills,

With cold I’m fed up to the gills

But none could say that we are quitters

We’ll search ‘til we find those little critters

 

Believe me, I know whereof I speak

You’ll find out fast if your waders leak

One hears screams of pain from the bravest jocks

When that icy water hits their socks

 

Collectors and runners can stay in motion

Stay warmer thus, I have a notion

But picking requires that one stand still

Can be quite bleak, cause many a chill

 

Don’t go on ice unless waders you wear

If you’re not wearing waders your weight it won’t bear

If you should venture this dumb thing to do

I guarantee you’ll surely break through

 

Let me warn you right now; listen up and take heed

Bring twice the wraps you think that you’ll need

That usually turns out to be about right

So that you are not left in a piteous plight

 

A jug of warm water is always quite pleasing

Helps to keep that D-net from freezing

And stout rubber gloves keep collectors’ hands dry

Help a great deal when frostbite is nigh

 

On these trips a truly most gracious amenity

May help the participants keep some of their sanity

A big jug of cocoa sure hits the spot

Beloved by all if it’s nice and hot.

Stonefly Search is coming January 23! Registration and info here.

About the author:

Dave Wilson is a HRWC volunteer and trained collector who has attended 9 Stonefly Searches and countless other HRWC events.

What’s hot and what’s not in the Huron River Watershed

Streams ranked from best to worst: Where does your favorite fall?

On October 3, HRWC volunteers spread across Oakland, Livingston, Washtenaw, and Wayne Counties and looked for the aquatic insects and crustaceans that indicate the water and habitat quality of our river and creeks.  

2014 10 18 RU by John Lloyd (8)

Sampling Traver Creek in October. credit: John Lloyd

Using this and other environmental data collected by HRWC volunteers over the past 20 years, I have developed a ranking of the various streams in the Huron River Watershed.  Streams listed at the top of this list have the best aquatic life and habitat in the Huron, and streams at the bottom of list are extremely impaired with little aquatic life and highly disturbed habitat.

Volunteer-collected data directly contributes to our knowledge of the conditions of the watershed and is a key component in directing management and restoration activities.

If you want more details on the ranking below, HRWC will present it and other data findings on January 12, 2016, 6 pm at our office (1100 N Main Street, Ann Arbor). All are welcome and no registration is required.

Ranking of Aquatic Life and Habitat (from best to worst)

Excellent

1. Huron Creek (Dexter)

2. Woodruff/Mann Creeks (Brighton)

3. Honey Creek (Pinckney)

4. Huron River (Upstream of Proud Lake)

Good

5. Woods Creek (Belleville)

6. Boyden Creek (west of Ann Arbor)

7. Pettibone Creek (Milford)

8. Fleming Creek (Ann Arbor)

9. Huron River (from Proud Lake downstream to Zeeb Road)

10. Portage Creek (Multiple townships to the northwest of Ann Arbor and north of Dexter)

11. Mill Creek (Dexter and Chelsea)

12. Hay Creek (east of Pinckney)

Fair

13. Arms Creek (Webster Township)

14. Huron River (Ann Arbor and downstream)

15. Davis Creek (South Lyon)

16. South Ore (Brighton)

17. Honey Creek (west of Ann Arbor)

18. Chilson Creek (west of Brighton)

Poor

19. Horseshoe Creek (Whitmore Lake)

20. Downriver Tributaries (Port Creek, Bancroft-Noles Drain near Flat Rock)

21. Traver Creek (Ann Arbor)

22. Malletts Creek (Ann Arbor)

23. Norton Creek (Wixom)

24. Swift Run (Ann Arbor)

25. Millers Creek (Ann Arbor)

Full River Roundup report is available for download.

 

Bird, Bats, Butterflies, and Dragonflies: Part 4

What is something that birds, bats, butterflies, and dragonflies all have in common?

Well, yes, they do fly.  But something that doesn’t occur to the typical person not well-versed in these animal types is that all of these creatures migrate.  Now that summer is done, the days are getting shorter, and the air is a bit cooler out there, we can expect to see these animals on the move soon.

This blog is the 4th part of a short series on migrating animals. The final topic: dragonflies!

The Commond Green Darner is the most abundant migrating dragonfly in the U.S. credit: U.S. Fish and Wildlife

The Commond Green Darner is the most abundant migrating dragonfly in the U.S. credit: U.S. Fish and Wildlife

Dragonflies

Of all four topics I am covering in this series, scientists seem to understand dragonfly migration the least.  This is likely because not much effort has been put into the subject: dragonflies are of not great economic importance, and the best known species that migrates, Common Green Darner, is widespread and abundant and so there is little concern about its future. In general, dragonflies are not very sensitive to water pollution, and can thrive in man-made or naturals wetlands. This is in contrast to some bat species and the Monarch butterfly, which are very specific in their over-wintering habitat selection.

Of the 326 species of dragonflies in North America, about 18 are regular migrants. Besides the Common Green Darner (Anax junius), other migrating dragonflies include the Wandering Glider (Pantala flavescens), Spot-winged glider (Pantala hymenaea), Black Saddlebags (Tramea lacerata) and Variegated Meadowhawk (Sympetrum corruptum).

The dragonfly life cycle

Dragonflies are fascinating creatures, with strange mating, flying, and territorial behaviors.  This complexity applies to migration as well, which certainly contributes to the sense that scientists have yet to unravel dragonfly migration.

For example, work done by entomologist R. Trottier in 1971 revealed Common Green Darner could adopt two distinct life-cycles.  One group of darners had the standard dragonfly life-cycle: nymphs emerged as adults in June, laid eggs in the summer, and died by late August.  The eggs would hatch into nymphs that would overwinter locally in the bottom of streams and ponds and then emerge again the next June. (Side note: Dragonflies spend 1-3 years in the nymph stage, depending on the species).

The other group of the darners did not emerge until late-August, and rapidly disappeared from local ponds and wetlands as they began a migration south. Their children would be the ones to return in early April and continue the generational cycle. In this population, migration is a normal part of the life cycle. In other words, just like the Monarch butterflies, dragonfly migration is a one-way ticket for any given individual. The first generation will travel south, reproduce and die, and the children will head north. They will reproduce and die and their children will go south.

However, not all dragonflies migrate, even within the same species. This is a complication that is not well understood.

Dragonfly swarming behavior. Photo copyright Steven Young and taken from http://www.flickr.com/photos/steven-young/2893876500/.

Dragonfly swarming behavior. Photo copyright Steven Young and taken from http://www.flickr.com/photos/steven-young/2893876500/.

Timing and Destination

In 2006, researchers attached micro-radio transmitters to Green Darners and followed them along their migration for 12 days. On average, they traveled 30-40 miles in a 5-7 day period, eventually going an average of 400 miles. Another study recorded a maximum observed distance of 2200 miles.

Like the other animals we have studied, dragonflies rest for several days at a time while on the migration route, so the total migration time can last many weeks.  From the Mid-West and Northeast United States, they are able to reach the Gulf Coast states and occasionally Mexico.

Cold nights seems to trigger dragonfly migration, just like with birds. Dragonflies will began their journey south in mid-August, and will continue through the end of October.  The dragonflies use northerly winds that follow from cold fronts to speed them on their way, and can be seen traveling in swarms of hundreds of thousands, though they also travel as individuals and small groups.

Like birds and butterflies, it seems like they navigate using some type of internal magnetic compass and using topographic features like lakeshores and coastlines. Another interesting observation in the 2006 study is that dragonflies can alter their migration route considerably (in this case, by 120 degrees) in order to avoid flying over large bodies of water.

Learn more!

Check out this webpage: Migratory Dragonfly Partnership.  This partnership is a collaborative effort between universities, dragonfly experts, the federal government, and nongovernmental programs with the goal of learning more about dragonfly migration.

The Partnership welcomes dragonfly observations from citizen scientists!

Thanks for reading!

It has been great fun for me to research these migrations and learn about new things (for me) that I had been wondering about for some time.  I hope you enjoyed the series too!

-Paul Steen, HRWC Aquatic Ecologist.

 

 

 


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