Tag Archives: #migration

Just Passing Through

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A flock of homing pigeons has taken up residence on our roof. How do we know they’re homing pigeons? They’re all banded, they’re very sleek and well-fed, and they seem a bit lost.

They stand on our skylights and look down at us with beaky expectation, as if we know what to do better than they. I think what they’d like to do is move on, but they’re not quite sure to where.

It’s migration season all over the world, creatures on the move. And whether out of habit, necessity or instinct, migration is always a dicey venture.

Billions of birds migrate every year, and every year it gets a little harder for them. Ornithologists at the Max-Planck Institute estimate that up to 10 billion migratory song birds don’t make it from their point of departure to their destination, and statistics are pointing to a 50 percent overall loss of the world’s songbird population in just the past 40 years.

Five of a flock of seven homing pigeons trying to figure out their next steps. Photos: PK Read

Four of a flock of seven homing pigeons trying to figure out their next steps.
Photos: PK Read

What’s happening?

There are the old culprits of hunting, with some cultures clinging to archaic trapping methods of capturing tiny birds that make barely a mouthful.
I think of these habits, which are worldwide and involve different birds in each region, and when they must have begun.
Was it out of a sense of longing, that the eating something so delicate and that sang so sweetly would somehow impart some of that fleeting beauty to clumsy, earthbound humans? Was it out of basic hunger and the seasonal availability? Was it out of a sense of plenty, just so many of damn things that putting a few dozen in a pie would make no difference?
These days, it seems like people do it just because they can. And old habits die hard.

Migratory bird routes mapped and animated by Movebank, a project of Max Planck Institute of Ornithology, which collects and communicates migration research for a wide variety of migratory animals. Source: Movebank

Migratory bird routes mapped and animated by Movebank, a project of Max Planck Institute of Ornithology, which collects and communicates migration research for a wide variety of migratory animals. Click here for a beautiful film of routes across Eurasia.
Source: Movebank

But beyond hunting, there are the bugaboos of climate change and, probably most relevant, habitat loss. Not just the habitats where the birds overwinter or breed, but the flyover areas. The navigational abilities of the migrating flocks are considerable, but can’t necessarily account for all the new human settlements in areas that used to be resting zones, or dark areas now illuminated by city lights, or absent wetlands, or all those windows that look like sky.

The good news is that there are a number of technological innovations and legislative solutions underway to try and stop some of the songbirds from ending up against a window instead of their summer home, or being confused by light smog.

What will our visiting pigeons do to find their way home? I wish I knew where they needed to go – they certainly keep looking in at me as if I do.

Hopefully, they’ll just be circling, as they do right now, and the right flight path will suddenly occur to them.IMG_1857

 

Speaking the Language

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I went to bed late last night, it was easily midnight or beyond, and as I lay there on the edge of sleep, I heard an unaccustomed sound. It sounded like…birdsong. I listened closely. It was, indeed, birdsong. And not just little chirps or the otherworldly radar sounds of an owl.

There were two birds, calling to one another, long, complicated tunes that sounded like they were being played on a glass harmonica.

My first thought was: Nightingale.

The Kitchenmaid Listens to the Nightingale. From: Henry Justice Ford in Lang, Andrew, Ed. The Yellow Fairy Book.

The Kitchenmaid Listens to the Nightingale.
From: Henry Justice Ford in Lang, Andrew, Ed. The Yellow Fairy Book

I thought of those lines from Shakespeare’s Romeo and Juliet:

JULIET
Wilt thou be gone? it is not yet near day:
It was the nightingale, and not the lark,
That pierced the fearful hollow of thine ear;
Nightly she sings on yon pomegranate-tree:
Believe me, love, it was the nightingale.

ROMEO
It was the lark, the herald of the morn,
No nightingale: look, love, what envious streaks
Do lace the severing clouds in yonder east…

Imagine knowing, eyes closed and in a darkened room, what time of day it is just by the type of birdsong on the air.

I thought to myself that I had no real idea what a lark sounded like, nor for that matter, a nightingale.

Rather, it was night time, the birdsong didn’t sound owl-like. It wasn’t the sharp chirps of the ever-present flock of sparrows that live in the vines on our house, and I know nightingales sing at night. Deductive reasoning, not actual familiarity.

The above video shows 3-D digital sound sculptures of nightingale and canary song, created by Australian artist Andy Thomas, who begins his work “by listening to the sound carefully, going for a walk, and concentrating on the sound.”

But do they sing in autumn?

Yes, apparently, because they are on a migratory route to the south for the winter.

Research has shown that songbirds share similar ‘gene products’ for vocalizations that humans use for speech. So what we hear as song might be, for the birds, a rich conversation, good as a book, engaging as a movie. Better, probably, because it’s theirs.

Early sketches of nightingale song for animation. Artist: Andy Thomas

Early sketches of nightingale song for animation.
Artist: Andy Thomas

After all, other research has shown that dolphins call each other by name, using a ‘signature whistle’ to identify themselves, and using others’ signatures to call individuals. And let’s not forget the mice who ‘sing’ to each other in ultrasonic melodies, and have vocalization brain patterns that resemble humans – and songbirds.

Think of all the conversations we are missing because we either can’t hear them, or don’t speak the language, or have forgotten how to listen.

What We Talk About When We Talk About War (VIII)

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Northern Bald Ibis (Geronticus eremita) Image via WildlifeExtra.com

Northern Bald Ibis (Geronticus eremita)
Image via WildlifeExtra.com

When I first wrote about the Northern Bald Ibis (Geronticus eremita) two years ago, the civil conflict in Syria had already been wreaking havoc on citizens and landscape for over 24 months. It was suspected that chemical weapons had been used on civilians, and historical monuments were being destroyed.

A bit of good news was that a tiny breeding group of northern bald ibis, once common around the Mediterranean and thought to have been extinct, had been discovered near Palmyra and was quietly expanding. One female, dubbed Zenobia, was still making the annual migratory crossing to Ethiopia. By the time I wrote my post in May 2013, she was the lone survivor of the group.

Back in May 2013, few had yet heard of a group calling themselves Islamic State of Iraq. Now this group, known as ISIS or DAESH, is notorious around the world for its expansion, media savvy, extreme brutality and wanton destruction, dismantling and sale of historical treasures.

The group captured the town of Palmyra this week and has been subjecting the place and its inhabitants to deplorable atrocities.

Amongst all this horror, the  guards assigned to protect four captive breeding ibis disappeared, as have the birds.

A northern bald ibis (Geronticus eremita). Photo: Waldrappteam

A northern bald ibis (Geronticus eremita). Photo: Waldrappteam

Meanwhile, Zenobia herself hasn’t been spotted. Even if the captive birds are recovered, if they are ever to be set free in the wild they will need a guide to the wintering grounds. Without Zenobia, they will remain captive. If they are found, of course.

As I wrote in my previous post, “The ibis was considered to be one of the first birds released by Noah off the Ark as a symbol of fertility, and in ancient Egypt the bird symbolized excellence, glory, honour, and virtue, as well as the signifier of the soul.”

The Society for the Protection of Nature in Lebanon told the BBC  that the species could go extinct in the wild in Syria.

Zenobia, the last wild ibis who knows the way to Ethiopia, was named for 3rd-century Queen Zenobia of Palmyra, a warrior queen who successfully protected Palmyra for many years against Roman expansion.

“Culture and nature they go hand in hand, and war stops, but nobody can bring back a species from extinction,” said head of the society Asaad Serhal.

Here’s hoping Zenobia takes after her namesake and returns to hold back the tide.

Queen Zenobia's Last Look Upon Palmyra Artist: Herbert Gustave Schmalz via Wikipedia

Queen Zenobia’s Last Look Upon Palmyra
Artist: Herbert Gustave Schmalz via Wikipedia

On a slightly more encouraging note: A project is underway in Europe to reintroduce the ibis 300 years after it went extinct in the region. But the challenges faced by that project underline how important it is to prevent local extinction in the first place.

 

 

Portrait of Living Wind

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Martha, the world's last passenger pigeon.  Photo: Scientific American

Martha, the world’s last passenger pigeon.
Photo: Scientific American

A century ago this month, the world’s last passenger pigeon (Ectopistes migratorius) died in the Cincinnati Zoo, long after the last passenger pigeon had been seen in the wild. The passenger pigeon, once populous beyond imagining, took only a century to disappear.

It seems that more than one factor was responsible for the population decline and how well the passenger pigeon thrived, from breeding habits (they bred communally in large flocks, and didn’t breed in captivity) to human influence (hunting, habitat loss and deforestation).

To a 19th-century European hunter sitting in the middle of a vast colony of the birds, though, it must have seemed like endless flocks of passenger pigeons were just the way of the world. When the first alarms were raised, including an 1857 bill in Ohio to control hunting and protect the birds, the overall response was simple disbelief.

Martha

Martha

“The passenger pigeon needs no protection. Wonderfully prolific, having the vast forests of the North as its breeding grounds, traveling hundreds of miles in search of food, it is here today and elsewhere tomorrow, and no ordinary destruction can lessen them, or be missed from the myriads that are yearly produced.” (Wikipedia) Subsequent efforts over the next 40 years were fruitless.

And so to the declines in the shorebirds of the Eastern Hemisphere, epic migrations that take place between Australia and the Arctic along the eastern coastlines of the Pacific Ocean and along the Yellow Sea. An estimated 36 bird species, their populations numbering in the hundreds of thousands, have used the flyway for most of human memory. Their numbers are dwindling. Very quickly.

Some species, including the curlew sandpiper, have seen their numbers collapse by up to 95% over the past few years alone. The culprits? Hunting, habitat loss, deforestation. And yes, there are several international agreements in place meant to protect migratory birds and their habitats.

It would seem the people doing the agreeing and the people doing the hunting and developing don’t share common goals.

Or maybe the hunters and developers and those who support their right to action just don’t believe in extinction.

Remains of the last confirmed wild passenger pigeon, shot by a boy with a BB gun in Ohio, March 1900. Source: Wikipedia

Remains of the last confirmed wild passenger pigeon, shot by a boy with a BB gun in Ohio, March 1900.
Source: Wikipedia

In 1947, Aldo Leopold said of the passenger pigeon, “Men still live who, in their youth, remember pigeons. Trees still live who, in their youth, were shaken by a living wind. But a decade hence only the oldest oaks will remember, and at long last only the hills will know.”

When will we, then the marshes, and finally the shores, begin to forget the last shorebird?

Or have we already begun?

 

Snake Compass

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Python skeleton Source: Worrapol Koranuntachai /123rf

Python skeleton
Source: Worrapol Koranuntachai /123rf

Burmese pythons (Python bivittatus) are a successful invasive species in Florida that have been profiting from local wildlife and few natural predators. Native to Southeast Asia and listed by the IUCN as vulnerable or endangered in their original habitats, abandoned or escaped pythons have been thriving in the Florida Everglades, to the dismay of conservationists trying to protect indigenous species there. Not much is known about how the snakes move or take up a new residence.

As it turns out, pythons have a distinct sense of  direction and territory when it comes to their habitat. A recent study published by the Royal Society journal Biology Letters suggests that pythons use a homing instinct to venture out from their usual territory and then find their way back.

A research team tracked several pythons – some of them trapped and removed miles away from their territories, some left in their adopted areas – to see whether the snakes that had been removed would be able to find their way home.

Source: Deimos in Flames / Deviantart

Source: Deimos in Flames / Deviantart

And indeed, all the relocated snakes demonstrated great determination to return to where they’d been captured in the first place. Most of them succeeded in finding their way back. The snakes which had been tagged and released without relocation moved around within a much more limited area, usually returning to their own territory.

The snakes clearly have both a ‘map sense’, which tells them where they are in relation to ‘home’, and a ‘compass sense’, which tells them in which direction to guide their movement. And it’s likely that this ability isn’t limited to the Burmese python – snake navigational abilities just haven’t yet been widely studied across many species.

According to this article, researchers say the internal python map “could be magnetic, like sea turtles, while the compass could be guided by the stars, olfactory (smell) cues, or by polarised sunlight – all of which have been shown to be used by reptiles.” Gaining knowledge of how snakes travel and navigate should prove useful in controlling their spread.

What I find interesting is how well the Burmese python has adjusted its internal compass to an entirely new corner of the planet from where it evolved. Having said that, another study published late last year suggests that Burmese pythons are among the most rapidly evolving vertebrates in the world.

How did the Burmese python learn to redefine home so quickly?

Source: gortan123/123rf

Source: gortan123/123rf

Reaching New Shores

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Circular plot of migration flows of at least 170,000 people between and within world regions during 2005 to 2010. Tick marks show the number of migrants (inflows and outflows) in millions.  Click to enlarge.  Image courtesy of Abel et al., Science/AAAS via Co.Exist

Circular plot of migration flows of at least 170,000 people between and within world regions during 2005 to 2010. Tick marks show the number of migrants (inflows and outflows) in millions.
Image: Abel et al., Science/AAAS via Co.Exist

The Intergovernmental Panel on Climate Change (IPCC) recently released a report on the development of climate change and its effects on humans.

The 2600-page report is the result of three years work and the collaboration of 300 scientists.

It makes for mostly grim reading, with an emphasis on climate impact on food security (not positive), on extreme weather events (increasing), and on poverty (again, not positive).

The global migration patterns in the interactive graphic above illustrate twenty years of migration statistics from 196 countries. Created by the Wittgenstein Centre for Demography and Human Capital in Vienna, the graphic uses software lifted from the field of genetic research.

It’s interesting to note that the number of people who actually leave their country of birth for good has remained at more or less the same level across decades – a mere 0.6% of the population. As a long-term expat among many long-term expats, it often seems like the number must be much higher, but such is the power of subjective perception. What we think we see up close isn’t always what’s happening if seen at a distance.

Quoted in Co.Exist, the authors say, “These long-distance flows are effective at redistributing population to countries with higher income levels, whereas return flows are negligible.” So, migration has been for mainly economic reasons, or for reasons of security offered in higher-income countries.

Given the IPCC report and its sobering conclusions regarding food security and extreme weather events, I wonder how these migration patterns and numbers will develop over the next few decades – which areas will see more migration inflow. The higher ground countries as well as those with higher-income?

Will we as humans follow many animals, flee an ever-warmer planetary midsection, and migrate north?

And what about that migration number of people who permanently leave their home country, 0.6%, that’s been steady for so long? Should climate change redraw the coastlines of continents and the boundaries of nations, what will count as ‘migration’ and what will count as keeping one’s head above water?

The World - Rising Sea Level, first map of its kind on such a scale and level of complexity, depicts our planet as it would look without its polar ice caps, with sea levels 260 ft higher as they are today. Click map for a larger version. Artist: Jay Simons

The World – Rising Sea Level, first map of its kind on such a scale and level of complexity, depicts our planet as it would look without its polar ice caps, with sea levels 260 ft higher as they are today. This detailed map can be viewed in all its glorious cartographic futurism by clicking on the map or following the link of the artist, Jay Simons.
Click map for a larger version.
Artist: Jay Simons

 

 

 

Sessile Mobility

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Sucker-footed bat Source: Guardian Live

Sucker-footed bat
Source: Guardian Live

A study on sucker-footed bats (Myzopoda aurita), published in PLOS One, discusses bat fossils found in Egypt’s Western Desert. This might be less worthy of examination if the fossils weren’t almost identical with existing bats now found only on Madagascar. These bats have sessile, or immovable, pads for feet.

Based on their research, study authors were able to reach a couple of interesting conclusions based on these tiny, ancient bat jaws. For one thing, the fossils provide evidence of a bat lineage that is 37 million years older than previously assumed.

Animated illustration of the break-up of Gondwana into present-day continents. Based on the bat fossils found, it's assumed that bats which originated in Africa, migrated into Australia, and were able to cross Antarctica into what is now South America. Source: Churchilll Science

Animated illustration of the break-up of Gondwana into present-day continents. Based on the bat fossils found, it’s assumed that bats which originated in Africa, migrated into Australia, and were able to cross Antarctica into what is now South America.
Source: Churchilll Science

This finding, in turn, provides evidence of when and how continental drift took place – the bats were apparently able to cross between continents while the land masses were either still attached, or while there were still dry land bridges between them. Continental drift contributed to the diversification of the bat family by separating and isolating their various groups. The sucker-footed bat was likely once more widespread.

Photo: Merlin D. Tuttle / Bat Conservation International

Photo: Merlin D. Tuttle / Bat Conservation International

In any case, the modern bat with the feet of a tree frog and that lives on Madagascar is the real reason I wanted to post this today. Because they are the only kind of bat that doesn’t hang upside, they live in palm fronds, they have ears that look like their palm frond homes, and they hang on to the slippery surface of leaves using feet that look like something from a child’s drawing.

Group of bats inside a palm leaf. Source: Arkive

Group of bats inside a palm leaf.
Source: Arkive

Narrowing Focus

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The monarch butterfly (Danaus plexippus) population on the Mexican Monarch Reserve where they overwinter is the lowest since annual surveys began back in 1993. The oyamel fir forests provide a warm winter home for the monarchs, known for their great migration across North America. The population is down 59% from two years ago. In 1996, monarchs occupied 45 acres (18.2 ha) of forest. They now occupy 2.94 acres (1.2 ha).

Monarch butterfly wing Photo: Rare Giants

Monarch butterfly wing
Photo: Rare Giants

The entire migration process takes five butterfly generations to complete one full cycle, and over the past twenty years, fewer monarchs have been surviving the cycle to have their progeny return to the reserve.

The demise of the milkweed plant, mainly due to the use of glyphosate herbicides, means the butterflies are unable to find enough of their main food source. But extreme weather, deforestation and forest degradation, and regulatory rollbacks for protected areas also contribute to the dangers facing the species’ survival.

In Barbara Kingsolver’s novel Flight Behavoior, monarch butterflies disappear from Mexico almost entirely and find a new forest home in a completely unexpected location, alighting for a season before moving on. There’s always the hope that intensified efforts to replant milkweed and to strengthen protected migratory paths will help. And maybe, prior to the annual surveys, the monarch population experienced massive contractions that went unnoticed, only to recover again.

Mexican billionaire Carlos Slim has just announced a $100 million contribution to a variety of monarch programs. If there’s message here, it’s this: If you live in North America, go out and plant some milkweed. In your garden, on your balcony, on roadsides and byways. Sign a petition. Send a letter to your congressperson.

For now, the circle of monarchs retracts, a narrowing lens by which to observe these amazing creatures of long journeys on small wings.

Photo: Raul Gonzales

Close-up, monarch butterfly wing
Photo: Raul Gonzales

Elvers Wait

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I’ve written several times before regarding the harvesting of elvers, the young of the American eel. It’s time for another update.

Once numerous, eel populations have dropped over the past hundred years due to a number of factors. Most of these have to do with man-made changes to the eel migration routes along the rivers of the eastern North American coastline.

More recently, there have been concerns about the possible overfishing of elvers, which are harvested and sold to stock eel aquaculture farms in Asia.

Via: glooskapandthefrog.org

Via: glooskapandthefrog.org

According to the Canadian Wildlife Federation, Canadian assessments of the American eel population levels have shown a 90% decline and as of 2007 the eel has been listed as Endangered under the Ontario Endangered Species Act. Elver harvesting is very strictly limited.

South of the Canadian border, however, the economic promise of high elver prices in a depressed economy has proven a strong incentive for delaying any far-reaching decisions on further regulations and licensing restrictions.

As reported in Maine’s Portland Herald: “The Atlantic States Marine Fisheries Commission’s (ASMFC) eel management board voted to postpone passing new regulations that would go into effect in 2014, opting instead to vote on new rules next spring that would be effective in 2015, (according to) commission spokeswoman Tina Berger.

“In the interim, state officials will work with eel fishermen and dealers in Maine to create a plan that results in next spring’s catch being 25 percent to 40 percent smaller than this year’s spring harvest.””

A handful of elvers Photo: AP via Portland Press

A handful of elvers
Photo: AP via Portland Press

And from the Bangor Daily News: ““There are no specific requirements imposed by the [ASMFC eel] board” on how the cuts are to be achieved, Berger said. “Maine will report back to the board in February regarding its intended plan of action.”

“Patrick Keliher, commissioner of DMR (Maine Department of Marine Resources), said (…) the delay in adopting new rules will allow regulators to include the most recent data on the elver fishery.

“This decision will also give me time to work with [the] industry to find common ground and an approach forward,” Keliher said.

“According to ASMFC officials, new requirements in an updated fishery management plan for the American eel fishery could include the allowance of glass eel fisheries in states where harvest is currently prohibited, a coastwide quota, monitoring requirements, enforcement measures and associated penalties, quota transferability and timely reporting.””

Eel fyke net Source: FishingTackle

Eel fyke net
Source: FishingTackle

New meetings between Maine state officials and fishermen have been taking place this month, during which the possibility of requiring licensed fishermen to record all sales via an electronic swipe card is being discussed.

Developing a state-wide plan must also include negotiating traditional elver fishing rights held by the Passamaquoddy tribe. The state has tried to set limits on the number of licences the tribe may issue, while the tribe maintains that the state resources board does not have the authority to set limits on its licensing.

The species currently is under review by the U.S. Fish and Wildlife Service for possible listing under the Endangered Species Act.

For me, the situation of the enigmatic American eel, endangered on one side of an international border and fair game on the other, continues to be a case study in the collision of economics, lack of scientific baselines and studies, local and regional politics, and the general lack of interest in the decline of an animal that is neither cute nor cuddly.

American eel (Anguilla rostro.) Image: Sidhat

American eel (Anguilla rostrata)
Image: Sidhat

EDIT: I have posted a brief update regarding the 2014 elver season here.

Following Green

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606x341_237086_groenland-sous-les-glaces-un-immensSome scientists are predicting that climate change will make Greenland, legendary for its otherworldly vistas, a place as green and verdant as Sweden or parts of Alaska. As species – both flora and fauna – migrate from their customary habitats, we will likely see the spread of more diversity, rather than less, into areas that were previously inhospitable or ice-covered.

There are very few species of tree  indigenous to Greenland, but commercial tree plantations have already been attempted in southern areas of the country, and I imagine given the value of commercial timber, this activity could increase.

If the ‘greening of Greenland’ process develops as predicted, it could offer a unique opportunity to see how plant and animal life colonize a region.

However, I could also envision a different kind of colonisation, the kind that didn’t take place earlier.

Ilulissat Icefjord, Greenland

Ilulissat Icefjord, Greenland

The ever-growing interest in land and mineral claims by surrounding countries to exploit resources exposed by retreating glaciers is well-known. As land becomes viable and interesting for increased habitation, might this expand to other land claims, coming up against the traditional shared land ownership of the various indigenous groups?

 

If climate change prompts plant migration away from the middle latitudes and towards the poles (especially the North Pole), might we not see more people wanting to follow the green?

Kuannersuit Glacier, Disko, Greenland Photo: Panoramio

Kuannersuit Glacier, Disko, Greenland
Photo: Panoramio

More:

The Guardian articleClimate change could turn Greenland green by 2100

AFP article (2008) – Stop stealing our land, Inuits say, as Arctic resources race heats up