Four Fascinating Swarming Phenomena

(Featured image taken by Ashraful Kadir)

Written by Matthew Durrant, who is studying Ecology at the University of York.

The sheer complexity of nature can sometimes be an overwhelming prospect to many of us, even very difficult to understand. Below are listed 4 cases of unusual biological events, which have led to the dramatic swarming of animals sometimes in unexplained ways.

1. Blackbird Swarm, Kentucky 2012

For Hopkinsville, a small town in the state of Kentucky, it looked to be a fairly normal November. But that was soon to change.  During the winter of 2011, a plague of blackbirds descended upon the small town, bringing large amounts of destruction as they prepared to make their home with the 35,000 local residents.

Each morning the residents would be woken up by the sheer intensity of the calling blackbirds as they made their way from the dense woodland close to the town and into the sky above, where their flight would block out light levels.

This seemed to be taking the term ‘a cloud of blackbirds’ to the next level.

Some residents even reported to CNN than they had to take umbrellas with them every time they left the house, so that they could avoid the immense amount of bird poo which appeared to be falling from the sky. Another resident commented that the trees around his home had turned white. To many locals, why their homes turned suddenly into an avian party, is a still a burning question that hasn’t received an answer.

However, it is not uncommon for stories such as this to happen, especially in the winter. It appears to be too easy for blackbirds and starlings, to name another example, to form such large groups and migrate.

Protection from predators perhaps? Or migration in aggregation to find more food on a colossal scale? The former is what enature blog suggests and past experiments to deal with situations such as these, usually have ended in more mess afterwards. The mass swarm of birds just appears to be yet another thing that we have to deal with other winter.

2. Turkey Swarm, Staten Island, New York, 2007

Photo by Lori Har-El/The Epoch Times

Photo by Lori Har-El/The Epoch Times

A Wild Turkey to most people would not be considered a nuisance, or even a pest. But to the residents of Staten Island, New York City, they have become a major problem to the local community.

The main roads, such as Hylan Boulevard have become swamped with these birds. On the Epoch Times, it was even reported that a whole line of traffic was stranded until the gaggle of turkeys took their time crossing the road. Each year the bands of populations seem to continue to keep growing in size and the local residents can do nothing about this, for wild turkeys are rightly protected under New York legislation.

However, this did not stop the unit of the Department of Agriculture from rounding up birds from a nearby psychiatric unit and sending them off to the slaughter house, which caused a public outcry from environmental and wildlife groups. To counter this, the department, reported by CBS, has started a programme instead to trap birds using the same techniques and send them off to a wildlife sanctuary instead.

It is clear that the local government needs a more clear strategy to manage and maintain the local populations of turkeys before the numbers become out of hand.

3. Tiny Frog Swarm, Greece, 2010

With the ever continuing financial crisis in Greece, a carpet of tiny frogs blanketing a major highway was the least of their problems. In May 2010, the police of Thessaloniki had to close the highway for two hours due to the sheer quantity of frogs that had made their way onto the road. Luckily, there were no injuries to humans or to frogs and it has been reported that the most probably cause for the sudden surge of frogs was due to the populations leaving a nearby lake to go in search of food.

4. Red Crab Swarm, Christmas Island, 2013

Out of the four phenomena listed in this article, the swarming of Red Crabs on Christmas Island has to be the most spectacular of all. CNN stated that the transition can occur for as long as up to 18 days during the annual migration cycle that these crabs undertake.

Each year, they leave their homes on the island and make their way across roads, grass and concrete towards the beaches, where they release their fertilised eggs into the sea. The whole spectacle involves a blanket of slowly moving crimson crossing the island and has been noted as a delight for enthusiasts and photographers.

Usually, the cycle begins in the autumn months, usually October-November (the beginning of the wet season on Christmas Island). This is dependent, however on the climatic conditions leading up to the season. If it has been too wet, then this can potentially delay the mass migration.

However, every year there is a high death rate among crab populations as they become crushed under cars as they make their way across the roads. This is why in 2012, the rangers of Christmas Island undertook many strategies to protect this very vulnerable species. Along the sides of the road, crab fencing has been erected, meaning that the crabs are diverted away from the oncoming traffic. These fences help to direct the crabs to grills, which act as underpasses so they can safely cross the road. Furthermore, rangers stand to the sides of the roads and sweep the crabs away from the cars as they come hurtling towards them. In some cases, roads too are closed once the migration is occurring.

Studies undertaken by the University of Bristol which are listed on National Geographic, have found that a surge in a hormone, that helps to metabolise an energy-producing sugar is what gives them the energy for such a long trip.

Have you experienced any strange swarming events where you live? Let us know! Leave a comment or send us an email!

Additional Source Articles:

Blackbird swarm Kentucky:

  1. http://www.huffingtonpost.com/2012/01/26/birds-invade-town_n_1233709.html
  2. http://magblog.audubon.org/blackbirds-swarm-kentucky-town-it%E2%80%99s-just-their-biology-not-sinister-attack

Turkey swarm:

  1. http://newyork.cbslocal.com/2013/09/21/twenty-five-wild-turkeys-from-staten-island-headed-for-hudson-valley-animal-sanctuary

Frog swarm:

  1. http://www.vosizneias.com/56330/2010/05/26/thessalonik-newest-greece-crisis-millions-of-frogs-tzfardeia-shuts-down-major-greek-highway/
  2. http://www.nydailynews.com/news/world/swarm-frogs-force-greek-police-close-major-highway-northern-greece-article-1.447779

Crab swarm:

  1. http://www.huffingtonpost.com/2013/03/25/red-crabs-swarm-island-christmas-island-migration_n_2950514.html
  2. http://news.nationalgeographic.co.uk/news/2010/08/photogalleries/100903-christmas-island-crabs-swarm-migration-science-pictures/
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