Our Beautiful World

Migrating birds and the risks



Bar-tailed Godwit, Limosa lapponica, World Record Holder for non-stop long distance flight.
Photo: Andreas Trepte, www.photo-natur.de



The Great Pacific Garbage Patch. Read more here
Ducks - or no Ducks? Is that a question to day? Read more here
The Amazing Journey - Lapwings migrating. Read more here


Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made
in response to changes in food availability, habitat, or weather. Sometimes, journeys are not termed "true migration"
because they are irregular (nomadism, invasions, irruptions) or in only one direction (dispersal, movement of young away
from natal area). Migration is marked by its annual seasonality.

In contrast, birds that are non-migratory are said to be resident or sedentary. Approximately 1800 of the world's
10,000 bird species are long-distance migrants.


Migration routes of birds based on Newton, I. 2008.
The Migration Ecology of Birds. Academic Press
More about
Arctic Tern, Ruff,

Many bird populations migrate long distances along a flyway. The most common pattern involves flying north in the
spring to breed in the temperate or Arctic summer and returning in the autumn to wintering grounds in warmer regions
to the south. (See Ruff, Philomachus puganx, on map above). Of course, in the Southern Hemisphere the directions
are reversed, but there is less land area in the far South to support long-distance migration.

See the Demoiselle Cranes fantastic journey across Himalaya here. (5 minutes video)

The primary motivation for migration appears to be food; for example, some hummingbirds choose not to migrate if fed
through the winter. Also, the longer days of the northern summer provide extended time for breeding birds to feed their
young. This helps diurnal birds to produce larger clutches than related non-migratory species that remain in the tropics.
As the days shorten in autumn, the birds return to warmer regions where the available food supply varies little with the
season.

Risks during migration. 1.

Populations of migratory birds are usually considered to be limited by conditions in breeding or wintering areas,
but some might be limited by conditions encountered on migration. This could occur at stopover sites where competition
for restricted food supplies can reduce subsequent survival or breeding success, or during the flights themselves, when
adverse weather can occasionally kill large numbers of individuals. Competition for food could act in a density-dependent
manner and help to regulate populations, whereas weather effects are more likely to act in a density-independent manner.

When preparing for migration, birds must normally obtain more food per day than usual, in order to accumulate the body
reserves that fuel their flights. Birds often concentrate in large numbers at particular stopover sites, where food can
become scarce, thus affecting migratory performance. Rates of weight gain, departure weights, and stopover durations
often correlate with food supplies at stopover sites, sometimes influencing the subsequent survival and reproductive
success of individuals, which can in turn affect subsequent breeding numbers.

Migrants in flight occasionally suffer substantial mortality in storms, especially over water, sometimes involving many
thousands of birds at a time. Other mass mortalities have resulted from atypical ‘winter-like’ weather, occurring soon after
the arrival of summer migrants in their breeding areas or just before their departure in autumn. Again, many thousands of
birds at a time have been killed in such incidents, causing reductions of 30–90% in local breeding densities. In some bird
species, migration-related events can at times have substantial effects on the year-to-year changes in breeding population
levels. Nonetheless, the difficulties involved in investigating migrating birds at different points on their migration routes have
so far limited the number of studies on the influence of events during migration periods on population levels.

From Journal of Ornithology, Volume 147, Number 2 (2006), 146-166, DOI: 10.1007/s10336-006-0058-4
Review : Can conditions experienced during migration limit the population levels of birds? by Ian Newton

Risks during migration. 2.

Malta and Cyprus are wellknown by birdlovers as virtual death traps to millions of migrating birds every year - and the
hunting that takes place is to a great extent illegal.

Cyprus and Malta are however far from the only countries in the Mediterranean area with an extensive, and remarkably
regular practice of illegal hunting of migrating birds. On the contrary, migrating birds are on principle hunted all the way
from Portugal in the west to Lebanon and Syria in the east. Of about 5 billion migrating birds passing through the
Mediterranean area each year, 500 million are shot or trapped. In other words: one migrating bird in ten is killed by
hunters in the Mediterranean!

Seen in the perspective of how extensive landscape changes, in particular intensive farming and forestry, has affected the
birds of Europe, hunting has long been treated as a minor problem. Nevertheless it has most likely had a significant
importance both locally and, for some vulnerable species, over a far wider area. A good example of this is the
Honey Buzzard
, Pernis apivorus, which has declined markedly in Scandinavia and which is shot in large numbers
every year in the Mediterranean area. Another example is the Ortolan Bunting, Emberiza hortulana. This species is
also declining in Scandinavia, and we can only speculate what effect hunting in France has had for some 50,000 birds
annually.



Ortolan Bunting, Emberiza hortulana
© - josef hlasek

Today, a great number of the migrating birds killed are consumed; but this has no longer any vital, if any importance at
all, for the national economy. Instead it has become a luxury consumption, when not regarded as preservation of tradition
- or merely a leisure activity where the prey is simply thrown away or (as in Malta) given to a taxidermist for stuffing so
that they can subsequently end up on a hunter's bookshelf.

Nowadays hunting is a large scale activity as in Cyprus where lime as well as mist nets are used, and as if this isn't enough,
tape-recorders with endless tapes of bird song are used. Sometimes whole plantations of shrubs are covered with up to
nine meter high mist nets or are prepared with lime sticks in the early evening. During the night the tape-recorder plays the
song of, for instance, the Blackcap, Sylvia atricapilla, and so attracts migrating birds. In the morning the nets and sticks
are emptied, and the catch often consists of hundreds or thousands of birds

Also, when it comes to hunting with fire-arms, there has been a considerable change for the worse for the birds during the
past few decades. While the hunters formerly used double-barrelled shot-guns that needed reloading after two shots,
most of the hunters today have semi-automatic shot-guns with several cartridges in the magazine. A passing bird has little
chance of getting away, especially when lines of hunters are posted along flight routes which the birds are obliged to use.



Red-legged Partridge, Alectoris rufa
Photo:
Arturo Nikolai

From an Ad on Internet:
Spain will capture your heart while enroute to the finest bird shooting in the world. In keeping with the old world charm and character of the jewel of Europe, xxxx will plan the
most exciting and authentic red-legged partridge shooting experience in existence.

You will have two full days of shooting followed by a day of sightseeing and then a third day of shooting. The expected bag is 500 downed birds per day for a group of eight to ten guns.

Every year, roughly 20 million migrating birds are killed in Cyprus. The majority of these birds are caught in mist nets,
traps or with lime sticks. Mainly warblers (primarily Blackcaps, Sylvia atricapilla, Bee-eaters, Merops apiaster,
urtle Doves, Streptopelia turtur, Robins, Erithacus rubecula, Nightingales, Luscinia megarhynchos, Song Thrushes,
Turdus philomelos and sparrows, Passer ssp. are caught. Thereafter the species not considered eatable are discarded.



Blackcap (Sylvia atricapilla)
Photo: © www.arthurgrosset.com

The remainder are sold as delicacies, and are said to bring up to1 GBP/1 Euro) apiece. In shops and restaurants they are
sold for more then 2 Euro). A complete dinner of small birds often consists of more than a dozen birds.

An example of an illegal and devastatingly efficient form of hunting is the so called baracca-hunt which is primarily
practised in Catalonia and Valencia in Spain. Artificial shrubberies, often rectangular in shape, are created with evergreen
trees. In these baraccas lime sticks are set out with a tape-recorder playing an endless tape of most usually Song Thrush
Turdus philomelos, song in the centre. During the night the song is heard and passing migrants are attracted. One single
baracca is said to trap up to 1,000 birds a night.



Song Thrush, Turdus philomelos
Photo: © www.arthurgrosset.com


Among the Song Thrushes other species such as Scops Owls, Otus scops and Little Owls, Athene noctua, also fall
victim to the traps. Hardly any hunter bothers to take the time to clear these collateral catches from the sticky lime; the
uneatable species are killed and discarded. This hunting method is forbidden but nevertheless widely practised.
A complicating fact is that it has an unofficial support among some politicians as it is regarded as a regional Catalonian or
Valencian tradition, with which the central government in Madrid (and even less the EU) have no business to interfere.
Source: http://proaction.tripod.com/infoandlinks/id8.html



© BirdLife Cyprus
BirdLife Cyprus has carried out monitoring of illegal trapping right through 2011 and discovered that
2.8 million birds have been victims of this practice during the year. It is the highest number of cases
reported since BirdLife Cyprus’ campaign against the illegal killing of birds was launched ten years ago.
This dramatic figure highlights the increasing trend in bird trapping in the country, which threatens to
reverse all the progresses achieved in the first years of the new millennium.

This post was written by: BirdLife Europe, http://www.birdlife.org/community/author/birdlife-europe/
downloaded May 18th, 2012

Risks during migration. 3.



Migratory birds flying above the col d'Iraty,
French Basque country.

© Franco Zecchin / Picturetank ZEF0184420

France is the country of hunting (2 times more hunters than in the UK), and the southwest is its paradise. From the 25th
of October until the 15th of November, from Bordeaux to Toulouse, a large part of the adult male population is all over
the Pyrenees mountains, hunting the "palombe bleue", the king of birds. The migratory wood pigeon (ring dove) flies
above the mountains during its annual migration from the north to the south of Europe. On the ground, thousands of
hunters are waiting. As many as 1,8 million of these birds are killed each year in the southwest of France, by more
than 100.000 hunters
Source: http://franco.zecchin.book.picturetank.com/___/series/e2848ef0fb853ebc7292071ca6888da8/a/Hunting_Frenzy.html



Ring Dove/Wood Pigeon
© Arthur Grosset

Bird-lovers and nature-lovers of France pay about 15.000 Euros, or US $ 25.000, for hiring a hill like the one on the
picture above, from Sept 15th ot Nov. 15th. They put up their binoculars and cameras, and count the birds passing
the Pyrenean Mountains, and they keep the hunters away from this place at least. But as shown on the picture, there
have been built hiding-places for the hunters all the way up to the top. During 1980 there were killed about
5.700.000 doves in the French part of the Pyreneans. Huntes also have to pay as much for the rights to sit on a hill,
and thay tells how popular this sport really is among the hunters.

For 13 hill-ridges the communities or other propertyowners receive about 300.000 US $ a year, which makes it
very difficult for them to stop this 'sport'.



Cranes in flight, another popular target while crossing the Pyreneans

The shelters on the ridges may range from a few up to 20 on larger ridges. In each shelter their are room for 1 to 8
hunters. Several thousand cranes also pass this area during the autumn, and are easy targets for the hunters, but
doubfully no value to the hunters when the cranes are shot.
Source: The book "Vårens Budbärare Tranan" (swedish) by Britt Traneving.

Most migrations begin with the birds starting off in a broad front. Often, this front narrows into one or more preferred routes
termed flyways. These routes typically follow mountain ranges or coastlines, sometimes rivers, and may take advantage of
updrafts and other wind patterns or avoid geographical barriers such as large stretches of open water. The specific routes
may be genetically programmed or learned to varying degrees. The routes taken on forward and return migration are often
different. A common pattern in North America is clockwise migration, where birds flying North tend to be further West,
and flying South tend to shift Eastwards.



Migrating waders in Roebuck Bay, Western Australia
Limosa lapponica and Thalasseus bergii,

http://en.wikipedia.org/wiki/File:Waders_in_flight_Roebuck_Bay.jpg

Many, if not most, birds migrate in flocks. For larger birds, flying in flocks reduces the energy cost. Geese in a V-formation
may conserve 12–20 % of the energy they would need to fly alone. Red Knots Calidris canutus and Dunlins Calidris alpina
were found in radar studies to fly 5 km per hour faster in flocks than when they were flying alone.



Black-tailed Godwit, Limosa limosa, Belgium
Photo: Hans Hillewaert

Birds fly at varying altitudes during migration. An expedition to Mt. Everest found skeletons of Pintail and Black-tailed Godwit
at 5000 m on the Khumbu Glacier. Bar-headed Geese have been recorded by GPS flying at up to 6,540 metres
while crossing the Himalayas, at the same time engaging in the highest rates of climb to altitude for any bird. Seabirds fly
low over water but gain altitude when crossing land, and the reverse pattern is seen in landbirds. However most bird
migration is in the range of 150 m to 600 m.

See the Demoiselle Cranes fantastic journey across Himalaya here. (5 minutes video)

Bird migration is not limited to birds that can fly. Most species of penguin migrate by swimming. These routes can cover
over 1000 km. Blue Grouse, Dendragapus obscurus, perform altitudinal migration mostly by walking. Emus in Australia
have been observed to undertake long-distance movements on foot during droughts.
Source: http://en.wikipedia.org/wiki/Bird_migration




Migration of the Bar-tailed Godwit Limosa lapponica
Map: United States Geological Survey,

Migration of the Bar-tailed Godwit Limosa lapponica.Bar-tailed Godwits have recently (March 2007) been shown to
undertake the longest non-stop flight of any bird. Using satellite tracking, birds in New Zealand were tagged and tracked
all the way to the Yellow Sea in China. According to Dr. Clive Minton (Australasian Wader Studies Group) "The distance
between these two locations is 9,575 km, but the actual track flown by the bird was 11,026 km. This is the longest known
non-stop flight of any bird. The flight took approximately nine days. At least three other Bar-tailed Godwits also appear to
have reached the Yellow Sea after non-stop flights from New Zealand."


One specific female of the flock, nicknamed "E7", (see story below) flew onward from China to Alaska and stayed there for
the breeding season. Then on 29 August 2007 she departed on a non-stop flight from the Avinof Peninsula in western Alaska
to the Piako River near Thames New Zealand, setting a new known flight record of 11,680 kilometres. Stray birds from
Europe and Asia occasionally appear on both North American coasts.



One Arctic Tern, Sterna paradisaea, ringed (banded) as a chick on the Farne Islands off the British east coast, reached Melbourne, Australia in just three months from fledging, a sea journey of over 22,000 km



The Story about the E7 flight


The famous female Bar-tailed Godwit, E7

Illustration of Earth showing the 29,000 km round-trip flight path from New Zealand
of the Bar-tailed Godwait dubbed "E7."

A female Bar-tailed Godwit, a large, streamlined shorebird, has touched down in New Zealand following an epic,
29,000 km long series of flights tracked by satellite, including the longest non-stop flight recorded for a land bird.

The U.S. Geological Survey's Alaska Science Center tracked the odyssey of the bird as part of an ongoing collaborative
effort with colleagues in California and New Zealand. The scientists were hoping to better understand potential
transmission of avian influenza by migratory birds.

The bird, dubbed "E7" after the tag on its upper leg, was captured along with 15 other godwits in New Zealand in early
February 2007. There each bird was fitted with a small, battery-powered satellite transmitter. USGS scientists hoped
the transmitters' batteries would last long enough to track the birds' northward migration to Alaska.

On March 17, E7 departed Miranda on the North Island of New Zealand and flew non-stop to Yalu Jiang, China,
completing the 11.000-km-long flight in about eight days. There she settled in for a 5-week-long layover before departing
for the breeding grounds.

On the evening of May 1, she headed east out over the Sea of Japan and the North Pacific, eventually turning northeast
towards Alaska, crossing the end of the Alaska Peninsula en route to her eventual nesting area on the Yukon-Kuskokwim
River Delta in western Alaska. This flight was also accomplished non-stop, covering some 7.250 km in five days.

E7 was then tracked to the coast of the Yukon Delta where she joined other godwits preparing for their return flight to
New Zealand.

On the early morning of August 29, she took off southeast back across the Alaska Peninsula, went out over the vast North
Pacific and headed towards the Hawaiian Islands. When less than a day's flight from the main Hawaiian Islands, she
turned southwest, crossing the Hawaiian Archipelago over open ocean 200 km west of Kauai, heading towards Fiji.
She crossed the dateline about 480km north-northeast of Fiji, and then appeared to fly directly over or slightly west of
Fiji, continuing south towards New Zealand.

In the early afternoon of September 7th she passed just offshore of North Cape, New Zealand, and then turned back
southeast, making landfall in the late evening at the mouth of a small river, eight miles east of where she had been captured
seven months earlier.

The last leg of E7's journey is the most extraordinary, entailing a non-stop flight of more than eight days and a distance of
11.500 km, the equivalent of making a roundtrip flight between New York and San Francisco, and then flying back again
to San Francisco without ever touching down.

Since they are land birds, godwits like E7 can't stop to eat or drink while flying over open-ocean. The constant flight speeds at which E7 was tracked by satellite indicate that she did not stop on land.

Godwits do not become adults until their 3rd or 4th year and many live beyond 20 years of age. If 29,000 km is an
average annual flight distance, then an adult godwit would fly some 460,000 km in a lifetime, or about 11,5 times around
the globe..

The study that recorded E7's epic flight is a collaborative effort led jointly by USGS and Point Reyes Conservation
Science, with cooperators from Massey University and Miranda Shorebird Centre, New Zealand, and The Global
Flyway Network. The project is funded by the David and Lucile Packard Foundation, the USGS, Alaska Science
Center, and the U.S. Fish and Wildlife Service.

For more information, or to track E7, the Bar-tailed Godwit, visit the Shorebird Research Web site.

Contact Information:
U.S. Department of the Interior, U.S. Geological Survey
Office of Communication
119 National Center
Reston, VA 20192 Mike Gauldin
Phone: 703-648-4447


Ducks - or no Ducks? Is that a question to day? Read more here

The Amazing Journey - Lapwings migrating. Read more here



bukkm.gif
ANIMALS

over 250

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BIRDS

over 500

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FLOWERS

over 225
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