Tagged: migration
Dragonfly Migration Watch
Most people know about monarch butterfly migration, but there are actually other insects in the US that migrate. That includes 16 species of American dragonflies!
Some researchers actually attached tiny radio transmitters to some Green Darners and followed their migration. The average distance migrated was 58 km (about 36 miles), but some dragonflies traveled twice that distance!
A paper from 1998 described mass autumn migrations of dragonflies (Odonata) in Illinois, New Jersey, and Florida. The description of the Chicago migration event is delightful–one of the authors was working in his office at the Field Museum and noticed a giant swarm of dragonflies passing by:
“The flux of migrants was estimated from the museum rooftop by counting dragonflies as they passed through a 400-M2 (40 m long X 10 m deep) vertical window to the E. …At the point where migrants were passing the museum, the dragonfly stream was estimated to be 850 m wide. Assuming that passage rates were constant throughout the 5-h period during which the migration was in progress, ca. 1.2 million dragonflies were estimated to have been involved in the flight.”
Would you like to help document more dragonfly migration?
The Migratory Dragonfly Partnership (MDP) has started a citizen science project to investigate the movements of two migratory dragonflies: the Common Green Darner (Anax junius) and Black Saddlebags (Tramea lacerata).
You agree to visit the same wetland or pond site on a regular basis, and then report the arrival of migrant dragonflies moving south in the fall or north in the spring. They also would like to know when the first resident adults of these species emerge in the spring. Sign up at Dragonfly Pond Watch
More info about migratory dragonflies:
- A nice PDF about migratory dragonflies
- Watch a video of a radio tagged dragonfly
- Teachers: there is a neat exercise for students on this topic!
Full details of papers:
Wikelski, M., Moskowitz, D., Adelman, J., Cochran, J., Wilcove, D., & May, M. (2006). Simple rules guide dragonfly migration Biology Letters, 2 (3), 325-329 DOI: 10.1098/rsbl.2006.0487
Russell, R., May, M., Soltesz, K., & Fitzpatrick, J. (1998). Massive Swarm Migrations of Dragonflies (Odonata) in Eastern North America The American Midland Naturalist, 140 (2), 325-342 DOI: 10.1674/0003-0031(1998)140[0325:MSMODO]2.0.CO;2
The Atmospheric Insect Highway
This is so AWESOME. Bonus: May Berenbaum.
Migratory Pollinators
I mentioned the book “Forgotten Pollinators” on Monday of National Pollinator Week, and I wanted to follow up on that today. The Arizona-Sonora Desert Museum (ASDM) hosts a Forgotten Pollinators Website to help focus interest on some of the lesser known migratory pollinators.
While pollinators in general are facing many threats, migratory pollinators are most at risk:
“While protection of plant/pollinator interactions is an emerging national priority, ecological conditions of migratory corridors for pollinators have received far less attention than conditions at wintering grounds in the south and breeding/birthing grounds in the north. “Nectar corridors,” a term first used by bat ecologist Ted Fleming (Fleming et al. 1993) specifically for pollinator corridors, are a distinctive type of migratory corridor comprised of a series of stepping stones placed in a dissimilar matrix. They are the migratory routes that pollinators follow in order to take advantage of a sequence of plants coming into bloom along a south-to-north gradient in the spring and the reverse in the fall.”
There has to be an actual sequence of flowering plants as the animals move north and south on their migrations. There also has to be safe roosting or resting sites for the animals as they travel.
A change at just one point in the migratory journey can spell disaster for a migrating population–and the plants they service:
“There is consensus among biologists that many migrant roost sites have already been lost, migratory corridor habitats have been converted or fragmented, invasive plant species are out competing many floral resources upon which these migrants depend, and many of the flowering plants these migrants visit are suffering low seed set due to pollen decline.”
While I am rather biased towards insect pollinators, ASDM also covers some of the mammalian and bird pollinators that are less well known.
If you live in a migratory corridor, consider planting some of the plants important for migrating pollinators.
This photo of courtesy of FreeSpirit5.
Golfer kills migratory raptor
One unexpected benefit of my travel was that I actually saw this story on CNN whilst trapped in an airport. I would have missed it otherwise, since I don’t watch much TV. I was going to write more about this, but Madhu at Reconciliation Ecology did such an great job, I’ll link to that post.
The background:
Pro Golfer was trying to film an instructional video. Migratory raptor made the mistake of nesting on the course, and trying to defend her nest. So, he shot at it with a golf ball.
Over. 10. Times.
Until he “accidentally” hit the bird and killed it.
Madhu dug up some additional info about the golf course not responding to an earlier offer by Audubon to move the nest–which would have presumably saved the bird’s life.
Of course, had the golfer not been an ass, that would have saved the bird too.
