Migration

Common Cranes on Migration
Photo © by semenov
Lac du Der France, 12 February, 2023

Migration

The need for migration

Birds migrate for two main reasons

• To move from areas of decreasing food or water supply to areas of increasing or high availability of food or water.
• To find suitable breeding sites.
  

The two are often linked, because areas of increased food supply are often in remote areas such as the Arctic Circle where daylight increases in the Summer months to peak at 24 hours a day, ideal to support vast numbers of insects and plants. These remote areas are not very accessible or desirable for human habitation and so provide good natural nesting sites.
Birds are quite resilient to cold and although migrating to avoid it is a factor, it is mainly the decreasing availability of food that drives the migration.
Many migratory birds are juveniles, making the journey for the first time without adult guidance. Some species migrate in different groups; these are defined by age and sex due to feather moult needs, or child rearing methods.

Migration triggers

Different species and even different populations within a species often have different triggers. This is not yet fully understood, but several factors are thought to trigger migration.

• Biological triggers which include hormonal changes and genetic influences which show as inborn ability.
• Changes in day lengths.
• Changes in temperature, which is strongly linked to:

• Weather conditions.
• Availability of food or water.

As changes in day length, temperature and food availability takes place, some species, particularly long distance migrants, have a biological pre-migratory response. Many long distance migrants moult before migration to ensure maximum efficiency of their plumage, as worn and abraided feathers lose efficiency over time. Another part of the preparation is a process known as hyperphagia It enables them to overeat, thus gaining the fat reserves (hyperlipogenesis) that are needed to survive the journey. Some species only lay down enough fat to reach the next staging post, where they fatten up for the onward journey. Others lay down enough reserves for a non-stop flight. Ruby-throated Hummingbirds can store 40% of their body weight in lipids for the migration across the Gulf of Mexico. It is a critical process, because too much weight takes more energy to get there and too little means starvation on route.

Types of migration

Migration may be considered not only in terms of length of distance travelled. Some species migrate between the high Arctic and Antarctic. Others travel much shorter distances between their breeding and wintering quarters, but also the methods used to achieve this. These include:

Loop migration

Birds use a different route for the Spring and Autumn migration. These are influenced by several factors.

Geography and weather conditions: Mountain ranges create natural barriers that channel birds naturally along their length, but if the weather conditions are right, certain families of raptors can utilise updrafts and thermals to save energy when travelling in one or both directions. (examples needed) On the opposite leg these conditions aren't there and they use a different route.

Food availability: some bird species, such as Eleonora's Falcon time their migration to follow swarms of migrating insects . These food sources are not available on return migration, so birds use other factors to decide the route used.

Altitude Migration

Where birds move from one altitude to a lower one and back. Usually, this takes place before winter when food becomes hard to find at higher altitudes, forcing them to move to lower levels. The birds then return when the snows melt. It is normally a mid range movement from one geographical area to another, but it can also occur over short distances when a birds moves down a valley to escape the worst of the snow.

Leapfrog Migration

Some species including Arctic Tern, Red Knot and Hudsonian Godwit move to the equivalent latitude in the opposite hemisphere on their winter migration, thus leapfrogging shorter range migrants who travel a shorter distance to the equivalent in latitude in the opposite hemisphere.

Drift Migration

High winds, mist or fog may cause migrating birds to be blown off course or lose orientation and fly off course. This is more prevalent during the Autumn migration with juveniles birds undergoing their first migration.

Reverse Migration

Some species of passerines have a gene that causes the first migration in juveniles. Yellow-breasted Bunting (further examples needed) If the gene responsible is faulty, this may cause the birds to fly in completely the wrong direction by 180 degrees.

Delayed migration

The effects of drought can cause delays in the Spring migration from birds leaving their wintering grounds in Africa. Global warming has caused delays in the Autumn migration for birds leaving their breeding grounds in the high Arctic.

Prolonged stopovers

Extremely cold weather in Europe causes a prolonged delay in the Spring migration. The birds have to wait until the snow and ice retreats before they can continue with their migration. Loss of suitably large stop over areas cause food shortages. Birds are forced to turn around and fly back to suitable sites.

Navigation

Birds have several methods by which they can navigate their way across the globe during migration.

The sun's azimuth

It is not the sun's height in the sky that some species use to navigate, but rather it's azimuth, the angle of the sun on the horizon. It has also been discovered that orientation using the sun is learnt early in life imprinting the data in the bird's memory. The circadian rhythm, the bird's inner clock if you like, has also to be synchronised with this.

Light polarisation

Light is polarised when daylight hits particles in the atmosphere and line up in a north/south direction particularly as the sun is setting. This alignment is thought to be seen by birds even when the sun is obscured by cloud.

Magnetic sense

The magnetic field of the Earth has three components: direction, angle and intensity. The direction of this field points to the magnetic North Pole. The angle is the angle between the magnetic field lines and the surface of the Earth The magnetic field variation around the globe can be used as a map, once the variations are learned by the bird. The intensity of the magnetic field can be used in a similar way to map migration routes.

Scientists believe that there are up to three ways that this works.

• Small iron oxide (magnetite) crystals could provide a compass.
  
• The magnetic field is seen by the bird’s eye.
  
• The bird's inner ear, it's sense of balance, enables it to "feel" the magnetic field.
  

Scientists currently think that birds have a compass in their eyes and a magnetic mapping device in their upper mandible.

Migration Routes

The main corridors that birds use are known as flyways. Their boundaries are not fixed and different authors recognise slightly different numbers of routes. They also vary somewhat according to the types of birds that are migrating: passerines tend to be more catholic in their choices resulting in them following fewer distinct paths. For example, in North America authorities often distinguish 4 flyways (Pacific, Central, Mississippi, Atlantic) based on movements of raptors and waterfowl. However, these might be better treated as only 3 for passerines [19],[20].

"Repeating world" map of key migration flyways
© by THE_FERN

World Flyways

Flyways are pathways that migrating birds utilise on their journeys. Siberia and the northern Americas have Arctic and subarctic breeding grounds which share a common starting point for several flyways. Birdlife International suggests there are 8 major routes around the world. Other authors may divide these up in slightly different ways. Here we discuss nine global Flyways.

American Flyways

Birds follow three or four main paths when they migrate through the Americas. The four routes we discuss below are based on those suggested by studies of waterbird and raptor migration. Passerines may follow three major paths.

Pacific Flyway

"Repeating world" map of the Pacific flyway
© by THE_FERN

Runs from the Siberian tundra through Alaska in the north down to Tierra del Fuego in the south along the eastern Pacific coastline. Over 300 species are known to use this flyway, including millions of wildfowl, passerines and waders. Stopover points along this route include:

• Copper River Delta, Alaska. Here, up to 1.1 million waders pass though during the peak Spring migration (April 25 – May 15). Vast numbers of Western Sandpiper and Dunlin C. a. pacifica, the most numerous waders of the Pacific Coast, stop here before migrating to their breeding areas. The estuarine mudflats between the barrier islands and the shoreline provide their main source of nourishment in the Gulf of Alaska. Access to these has a major influence on their ability to reproduce further north and west in both Alaska and Siberia. The upland marshes are significant in value for other waders that reproduce there: Short-billed Dowitcher, Least Sandpiper, Greater Yellowlegs, Wilson's Snipe, Red-necked Phalarope, Spotted Sandpiper, Semipalmated Plover and to a lesser extent, Lesser Yellowlegs.

• Fraser River estuary, Canada. These coastal wetlands provide support for over 1.4 million waders including Western Sandpiper; 240,000 waterfowl including Snow Geese and about 4,000 raptors like Barn Owl, Bald Eagle and Peregrine Falcon. There are 262 bird species, (Jun 2021), in the Delta, 65% are migratory.

• Old Crow Flats, Yukon Territory. up to 300,000 birds nest in this region. They are joined in the post-breeding period by more birds arriving to moult, fatten up and prepare for migration.

• Stikine River Delta, Alaska. This provides food for up to three million migrating birds annually including 14,000 Snow Goose, over 10,000 Sandhill Cranes, up to 164,000 Western Sandpiper and nearly 2000 Bald and Golden Eagles

• Point Reyes National Seashore, California. 38°4′N 122°53′W. 71,028-acre (287.44 km2). Nearly half of the bird species seen in mainland Canada and the USA and 2/3 of wader/shorebird species have been seen at Point Reyes. Point Reyes National Seashore lies at a vital point for wintering birds and passage migrants. A full list of bird species is given on the Point Reyes page.

• Panama. More than one million waders use the Upper Bay to refuel, or overwinter. This includes 165,000 Semipalmated Sandpipers and 30,000 Semipalmated Plovers. Austral migrants also visit Panama during the southern winter. These include Brown-chested Martin, Blue-and-white Swallow and Pearly-breasted Cuckoo. The need for protecting overwintering locations is therefore important during both the southern and northern winters. The pressure on land use for suitable conservation sites effectively doubles.

• Ecuador. Humedales de Pacoa, especially the area between Monteverde and San Pablo is visited by 20-30,000 Wilson's Phalarope that overwinter in the lagoons along the coast. Other neararctic migrants reaching Ecuador include Blackburnian Warbler, Canada Warbler and American Redstart.

• Peru. The Laguna de Ite in southern Peru provides and important wintering site for Elegant Tern. Boreal Common Terns and Elegant Terns also overwinter further north near Mollendo. Peru has 79 boreal and 42 austral regular migrant bird species. In addition a further 20 species migrate regularly from the southern oceans and tropical islands, and 4 species from the Galapagos Archipelago. 7.8 % of all Peru's birds are migratory. Accidentals and rarities make up a further 49 species but these are not included in theses figures.

• Chile. Chiloé Archipelago and Isla Grande de Tierra del Fuego About 25,000 North American Hudsonian Godwits and Red Knots migrate to their wintering grounds in the salt marshes of the Chiloé Archipelago and to the Isla Grande de Tierra del Fuego's northern shore.

Central Flyway

"Repeating world" map of the Central flyway
© by THE_FERN

Starts in the Arctic, moves south through the Great Plains of Canada and the United States of America (USA), the western seaboard of the Gulf of Mexico and southwards to Patagonia. The main endpoints of the flyway are in central Canada and the Gulf coast of Mexico, but some species use it to migrate from the high Arctic to Patagonia. (examples needed). The route narrows along the Platte and Missouri rivers of central and eastern Nebraska, which gives a high species count there.

The following states lie within the flyway: Montana, Wyoming, Colorado, New Mexico, Texas, Oklahoma, Kansas, [[Nebraska], South Dakota, and North Dakota. In Canada the flyway comprises the provinces of Alberta and Saskatchewan and the Northwest Territories

Mississippi Flyway

"Repeating world" map of the Mississippi flyway
© by THE_FERN

Over 325 bird species use the Mississippi Flyway, for their round-trip each year from their breeding grounds in Canada and the northern USA to their wintering grounds along the Gulf of Mexico and in Central and South America. It is a corridor comprising the states of Alabama, Arkansas, Indiana, Illinois, Iowa, Kentucky, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Ohio, Tennessee, Wisconsin and the Canadian provinces of Saskatchewan, Manitoba and Ontario.

Atlantic Flyway

"Repeating world" map of the Atlantic flyway
© by THE_FERN

Starting at the Arctic's Baffin Island in the north this flyway stretches ever south to the Caribbean and spans more than 3,000 miles or 4,828 km and includes the USA states of Connecticut, Delaware, Florida, Georgia, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Pennsylvania, Rhode Island, South Carolina, Vermont, Virginia, and West Virginia. In Canada, it includes the provinces of Newfoundland, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec and the territory of Nunavut. This flyway also reaches Greenland. It is the eastern most flyway in North America. About 500 species of birds use this flyway.
Birdlife combines the Atlantic with part of the Mississippi Flyway in its "Atlantic Americas" Flyway. This may be appropriate if the focus is passerines or perhaps all bird groups.

Alternative view of routes through the Americas

Two alternative views of major flyways in the Americas
A) The approach we discuss here source? B) Birdlife International's flyways
© by THE_FERN

Birdlife International identifies three major migration routes through the Americas: the "Atlantic Americas", "Central Americas", and "Pacific Americas" Flyways. The broadly cover the same areas as the four routes we discuss above although details differ. The "Central Americas" route is roughly equivalent to the combination of the "Central" and "Mississippi" Flyways. Birdlife's flyways show that some other routes encompass parts of high latitude North America: the primarily Asian "East Asian - East Africa" and "East Asian - Australasian" Flyways extend to include parts of Alaska. Conversely, the "Pacific Americas" Flyway includes parts of north-eastern Siberia. In the east, the "East Atlantic" Flyway includes Baffin Island.

Austral migration

Austral migrants are species of birds that breed in the temperate areas of South America and move north into areas including the Pantanal the Amazon basin and more rarely, as far as the Caribbean for the Austral Winter and return in the Spring. They include many species of ducks and geese and passerines such as the largest group, the tyrant flycatchers. Brown-chested Martin, Blue-and-white Swallow, Pearly-breasted Cuckoo are among the notable Austral migrants that reach Panama for the southern Winter.

Afro-palearctic Flyways

Birds migrating to Africa take one of three main routes.

East Atlantic Flyway

"Repeating world" map of the East Atlantic flyway
© by THE_FERN

For boreal breeders, their journey starts at various points in the high Arctic. These include;

• Bylot Island is a migratory bird sanctuary in the Canadian Territory of Nunavut, in the high arctic, next to Baffin Island. Migratory breeding species include; 100,000 Snow Goose, Arctic Tern, Red Knot, Glaucous Gull, Sabine's Gull, American Golden Plover, Black-bellied Plover, Common Ringed Plover, Horned Lark, Long-tailed Jaeger, Northern Wheatear, Pectoral Sandpiper, Ruddy Turnstone, Snow Bunting, White-rumped Sandpiper, King Eider, Long-tailed Duck, Red-throated Loon and Sandhill Crane. 300,000 Thick-billed Murre and 50,000 [Black-legged Kittiwake]] are also key breeding species dispersing to the sea.
  

• Iceland Iceland provides 121 Important Bird Areas. These involve up to four uses; breeding, staging, moulting and wintering. Several sites are used for all four including Lake Mývatn and Breidafjordur and the Snaefellsnes Peninsula. Passage migrants include; Greater White-fronted Goose A. a. flavirostris, Barnacle Goose, Brant Goose, Red Knot, Sanderling, Ruddy Turnstone, Long-tailed Jaeger, Pomarine Jaeger, Pink-footed Goose, Dunlin and Snow Bunting. Their journey continues to stop over points in Shetland and many overwinter in the British Isles, or continue south along the coast of Scotland to East Anglia on England's east coast before they cross the North Sea.
  

• Novaya Semlya breeders starting their journey from Novaya Semlya in Siberia, reach the Wadden Sea via the Baltic Sea.
  

• Olonets Plains in Russia host over 500,000 Greater White-fronted Geese and more than 200,000 Bean Geese.
  

• Falsterbo Scandinavian birds make the crossing to Denmark funnel through here. about 730,000 Common Chaffinch, 208,000 Common Wood Pigeon, 121,000 Common Starling, 87,000 Common Eider, 38,000 Yellow Wagtail, 32,000 European Greenfinch, 32,000 Eurasian Jackdaw, 27,000 Eurasian Siskin, 24,000 Common Linnet, 22,000 Barn Swallow, 20,000 Eurasian Blue Tit, 19,000 Tree Pipit, 16,000 Eurasian Sparrowhawk, 14,000 Common Buzzard, 9,000 Fieldfare, 8,000 Meadow Pipit, 7,500 Stock Dove, 7,500 Honey Buzzard, 7,500 Brent Goose and 7,100 Rook have been counted on average in autumn between 1973 and 2003 and are the 20 most common species counted at Nabben, south of the lighthouse.
  

• Wadden Sea. This is a system of tidal mudflats following the coastline from Denmark through Germany to the Netherlands. A series of Islands on the outer edges of the mud provides an outer frame to the Wadden Sea, before dropping off into deeper water. It is at a major cross roads of the eastern and western routes at the northern edge of the East-Atlantic Flyway. The mudflats provide a much needed supply of food for nearly 1,000,000 ground-breeding birds from 31 species that use this UNESCO world heritage site. 41 migratory waterbird species moult here, or transit the flyway through this area. In the milder more recent years, it provides a safe haven for wintering species. Approximate numbers include; 256,000 Eurasian Oystercatcher, 84,000 Black-tailed Godwit, 61,000 Eurasian Wigeon. All of the European and Western Russian populations of the 183,000 Dunlin and nearly all of the over 180,000 dark bellied Brent Goose use the Wadden Sea during their annual migration. The total number of birds that use the area annually reaches roughly 12 million. This makes the Wadden Sea one of the most important areas for water bird species in the world.
  

• Straits of Gibraltar. One the greatest hurdles for migratory birds to overcome is large bodies of water. The Straights of Gibraltar is the shortest way over the Mediterranean Sea that have to be navigated between the continents of Europe and Africa. In reality, there is a wider corridor that is used. Tarifa may be the closest place to North Africa on the southern Iberian coastline at 14 kilometers, but other places as far away as Sagres in Portugal are also used for arrivals and departures. Wind direction and strength determine whether birds set off or wait for better conditions. The straits of Gibraltar is probably the best place in Western Europe to see the visible migration (vismig) of up to 30 of soaring species such as raptors and storks. 250,000 - 300,000 raptors and 150,000 Storks make the crossing each season. Average species counts include; 150,000 White Stork, 4,000 Black Stork, 68,000 Honey Buzzard, for some of the 170,000 spring and 230,000 autumn crossings by Black Kite, different routes are used, 3,300 Egyptian Vulture, 10,000 Griffon Vulture, 18,000 Short-toed Eagle and 26,000 Booted Eagle.
  

• Banc d'Arguin National Park. Following the West African coastline there are major stopovers or end points at the Banc d'Arguin National Park in Mauritania, where 2.25 million Waders overwinter. Species include; 100,000s Dunlin, Bar-tailed Godwit, Red Knot and Curlew Sandpiper, 10,000s Greater Flamingo, Common Ringed Plover, Common Redshank, Eurasian Curlew, Eurasian Whimbrel and Black-bellied Plover. The 40,000 breeding pairs at this site include; Great White Pelican, Reed Cormorant 3 subspecies, Eurasian Spoonbill P. l. leucorodia and P. l. balsaci, Caspian Tern, Royal Tern, little Tern, Bridled Tern, Gull-billed Tern and Common Tern, Grey-headed Gull, Slender-billed Gull, Lesser Black-backed Gull, the endemic Grey Heron A. c. monicae, Western Reef Heron and Nubian Bustard. Cap Blanc birds include; Ruddy Turnstone, Sandwich Tern and Corncrake.

• Djoudj wetland in Senegal, where 2 million Sand Martins find their wintering quarters. This wetland area of 16,000 hectares, involves a large lake surrounded by ponds, streams and backwaters in the Senegal River delta. It has National Park status as well as being an UNESCO world heritage centre. Due to the completion of the Diama Dam project downstream, the natural flooding found in the rainy season (July to September), no longer occurs naturally. However, controlled flooding is carried out by opening sluice gates during the rains, which simulates the natural process. The area is allowed to dry out during the rest of the year. This National Park plays host to about 365 species of birds, including 120 migrants that use the East Atlantic Flyway. The migrants include; 250,000+ Northern Pintail, 200,000 Ruff and 180,000+ Garganey, all of whom overwinter at Djoudj. Breeding species include; 8,750 White-faced Whistling-Duck, 820 Fulvous Whistling-Duck, 640 Spur-winged Goose and 5,000 Great White Pelican.
  
• Arquipélago dos Bijagós mudflats in Guinea-Bissau which support over 500,000 waders.

Little is understood about migration further south along central and Southern Africa.

Mediterranean - Black Sea Flyway

"Repeating world" map of the Mediterranean-Black Sea flyway
© by THE_FERN

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East Asia - East Africa Flyway

"Repeating world" map of the East Asia-East Africa flyway
© by THE_FERN

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Asian Flyways

Central Asian Flyway

"Repeating world" map of the Central Asian flyway
© by THE_FERN

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East Asian - Australasian Flyway

"Repeating world" map of the East Asian-Australasian flyway
© by THE_FERN

The East Asian - Australasian Flyway (EAAF) starts in the high Arctic. On the Asian side it covers a large part of Siberia and reahes as far west as the Ural mountains and Novaya Zemlya in the north. In North America it stretches to the Banks and Victoria Islands in the north and Alaska and the Aleutian Islands. From there it crosses the Pacific Ocean to just south of the Kamchatka Peninsula and just east of Japan through the Northern Mariana Islands and down to the Solomon Islands, New Caledonia, Norfolk Islands and New Zealand. The central Asian boundary follows the Urals, then crosses to the eastern edge of the Plateau of Tibet, the Bay of Bengal, the East coast of India and Sri Lanka. It then crosses the Indian Ocean and skirts south west of Sumatra, Java and the west coast of Australia. The final leg reaches along the southern edge of Australia, Tasmania then across the Tasman Sea to New Zealands southern islands.
50 million water birds use this Flyway each year including 8 million waders. Important stopovers include:

• The lower Moroshechnaya River, Russia. This staging area is a gathering point for 27 wader species including Nordmann's Greenshank and Spoon-billed Sandpiper. In spring, the estuary hosts more than 400,000 birds. Ten species, including Dunlin C. a. kistchinski, Eurasian Oystercatcher and Eastern Curlew breed in the lower Moroshechnaya area. Thousands of Great Knot and Bar-tailed Godwit and hundreds of Eastern Curlew appear in July for the breeding season. At least 100,000 Whimbrel and Bar-tailed Godwit move through the lower Moroshechnaya during late summer and autumn. At least one million waders and 10,000s of wildfowl stage at the river estuary during the autumn journey south.

• Dandong Yalu Jiang, China. This stopover site is in the North of the Yellow Sea. It is of major importance to the EAAF and to the Trans-Pacific Flyway, as this is one of the crossover points between the two. This nature reserve supports about 50 wader species. An estimated 250,000 stage through the site during their northward migration, including Bar-tailed Godwit and Great Knot.

• Chiku Wetlands, Taiwan. These wetlands are of critical importance to the Black-faced Spoonbill. About 350-500 overwinter here. A conservation project stopped the building of an industrial plant and gave the area protected status.

• Inner Deep Bay and Shenzhen River Catchment Area, Hong Kong, China. On the 4th September 1995, the Inner Deep Bay, including the Mai Po Nature Reserve were declared a Ramsar Site. This key area and the Shenzen catchment area is important not only for 20% of the world's Black-faced Spoonbill population and the critically endangered Spoon-billed Sandpiper. 13 of the 26 bird species that can be found here in significant numbers are globally threatened. Habitat is gated intertidal fish and shrimp ponds known as Gei wais and mud flats enclosed with dwarf mangroves. Each Gei wai is drained systematically for long periods during the winter. This refreshes their bounty and provides a continuous food source for the overwintering birds. 17 new species of invertebrates have also been found here.

• Philippines. The Olango Island Wildlife Sanctuary is one of six Ramsar wetlands in the country. This site is surrounded by intertidal coraline sandflats and mangroves with coral reefs and seagrass beds in an area dotted with small islands. The habitat is suitable for both waterbird stopover and overwintering. An Important Bird Area for significant numbers of migratory waterbirds, the sanctuary takes up 5,800 hectares in the southwest of Olango island and coastal area. 48 of the 77 migratory bird species found in the region have been recorded at the sanctuary, including: Asian Dowitcher, Chinese Egret, Bar-tailed Godwit, Common Greenshank, Common Redshank, Common Sandpiper, Curlew Sandpiper, Eurasian Curlew, Far Eastern Curlew, Great Knot, Greater Sand Plover, Grey Plover, Grey-tailed Tattler, Gull-billed Tern, Kentish Plover, Little Egret, Red-necked Stint, Ruddy Turnstone, Striated Heron, Terek Sandpiper, Whimbrel and Whiskered Tern

• Limboto Lake, Sulawesi, Indonesia. There is a poor understanding of the ecology of landbird migration though tropical Asia. Deforestation is a major factor for loss of habitat for overwintering passerines. Deforestation leads to increased sedimentation of the lakes and waterways thoughout Indonesia, affecting waterbird migration. Limboto Lake is one of the 17 critically sedimented lakes in Indonesia. A enviromental birding group has increased awareness, leading to a national agency for cleaning up these lakes. Restoration has begun to restore environments such as Lake Limboto, where 85 bird species occur, 49 of which are migratory. Awareness of the knock on effects of logging and education concerning the use of invasive plant species for fish nuseries by local fishermen will lead to changes in the methods used.

• Papua New Guinea (PNG). The Tonda Wildlife Management Area (TWMA) in southwestern PNG shares a border with the Wasur National Park in Indonesia and the Kakadu National Park in Australia. It has an area of 590,000 Ha, or 2278 square miles. This gives the area protected a total of 1.3 million Ha (131,000 square kilometers), or 50,579.4 square miles. These wetlands provide habitat for over 250 species of migratory and resident waterbird species and as a drought refuge. Most of the world population of Little Curlew stage through the TWMA.

• Australia. Most bird movement in Australia is due to the unavailability of water. The southwest of the Gulf of Carpentaria, Queensland, has several sites for migratory waterbirds. They include: Over 72,000 Great Knot, about 27,000 Black-tailed Godwit and more than 25,000 non-breeding Little Curlew at peak counts. Eighty Mile Beach in Western Australia provides habitat for peak counts of over 2.8 million Oriental Pratincole, around 167,000 ((Great Knot]] and nearly 94,000 Bar-tailed Godwit. 350,000 Red-necked Stint migrate to Southern Australia.

• Passerines and Near-Passerines. Many near- and passerine boreal breeders migrate south into southern Asia. As tracking devices get smaller, small bird movements will be able to be tracked more efficiently giving conservationists a better idea of where to prioritise their efforts. A few that migrate from Fenno-Scandia include; Arctic Warbler, Red-flanked Bluetail and Rustic Bunting. Those migrating from the northern hemisphere to Australia comprise only about 10 species, including; Yellow Wagtail, Fork-tailed Swift, Oriental Cuckoo and the ubiquitous Barn Swallow. Very few reach further than the far north of Australia.

• Austral Migration. Austral breeders generally do not regularly migrate in Australasia. There are some exceptions.
• Australian species that migrate within the country include;
• Baillon's Crake Z. p. palustris The population that breeds in southern Australia, winters to north.
• Scarlet Myzomela migrates north in the austral autumn and return in the spring using the eastern coastline.
• Yellow-faced Honeyeater also migrates north in the austral autumn, returning in the spring using the eastern seaboard.
• Welcome Swallow H.n. neoxena breeds in south-eastern and eastern Australia, including Tasmania, with some migrating north to north-eastern Australia.
• Tasmanian breeders that cross the Bass Strait include;
• Silvereye Z. l. lateralis breeds in Tasmania and Flinders Island (Bass Strait), winters to coastal eastern Australia.
• Swift Parrot Breeds in Tasmania, winters to south-east mainland Australia.
• Orange-bellied Parrot Breeds in south-western Tasmania, winters to coastal south-eastern Australia.
• New Zealand's breeding migrants that cross the Tasman Sea, include;
• Double-banded Plover
• New Zealand's South Island breeding migrants that cross the Cook Strait include;
• Wrybill Endemic to New Zealand. Breeds in northern river beds on South Island and winters to North Island.
• Black Stilt is restricted during the breeding season to the upper Waitaki Valley, South Island. Small numbers overwinter to North Island.

• Those moving outside Australasia include;
• Shining Bronze Cuckoo C.l. lucidus breeds in New Zealand and winters to northern Melanesia, C.l.plagosus breeds in southern Australia and Tasmania and winters to Queensland and northern Melanesia.
• Australian Pratincole breeds in Australia and winters to southern New Guinea and Greater Sundas.
• Buff-breasted Paradise Kingfisher T. s. sylvia Breeds in northern Queensland and winters to New Guinea.
• Channel-billed Cuckoo S. n. novaehollandiae breeds in northern and eastern Australia and winters to New Guinea, Lesser Sundas, and Moluccas
• Long-tailed Koel Breeds in New Zealand and smaller islands within 100 km of the main islands. Migrates to Oceania, found in non-breeding season in Palau, Carolines and Marshalls through Fiji, Tonga and Samoa to Cook, Society Islands, Marquesas and and Pitcairn Islands. Also on Bismarck Archipelago, Solomons, Vanuatu, Norfolk Island, Lord Howe Island and on various other islands.
• Pacific Koel E. o. subcyanocephalus Breeds northwestern Australia to northwestern Queensland, winters to southern Moluccas. E. o. cyanocephalus Breeds northern Queensland to southern New South Wales, winters to Moluccas.
• Horsfield's Bronze Cuckoo Breeds in Australia including Tasmania. Winters to Java and irregularly beyond (e.g. Singapore)
• Sacred Kingfisher T. s. sanctus Breeds in Australia to the Solomon Islands, winters to New Guinea.
• Rainbow Bee-eater Breeds in Australia, eastern Indonesia and New Guinea. Winters to Northern Australia, Sulawesi, the Banda Arc and New Guinea.
• Australian Pelican Breeds Australia and Tasmania, winters to New Guinea.
• Brush Cuckoo C. v. variolosus (Australian Brush Cuckoo) Breeds northern and eastern Australia, winters to Moluccas and New Guinea
• Torresian Imperial Pigeon The Australian Top End Northern Territories populations are migratory, crossing the Torres Strait from New Guinea in August and departing by April.
• Pied Stilt Breeds from Indonesia to Australia and New Zealand, winters to the Philippines.
• Australian Hobby F. l. longipennis Breeds southwestern and southeastern Australia and Tasmania. It is partially migratory, winters to the Moluccas, New Guinea, and New Britain
• Plumed Egret Australian birds may winter to New Guinea.

Trans-Pacific Flyway

Some references used in this article do not give the trans-Pacific movement of birds a flyway name. For the sake of this article, it is as good a name as any for grouping together the movement of migratory birds through this region.

The flyway goes from the Arctic ocean crossing the Pacific Ocean using several routes described later and on to destinations from between the Tasman Sea between Australia and New Zealand and French Polynesia. Breeding sites occur mainly on route including the Arctic and Sub-Arctic regions of Alaska, Canada, eastern Asia and the Aleutian Islands. Large numbers of remote Pacific islands are in this flyway including the Hawaiian Islands chain, the Northern Mariana Islands, Guam, Marshall Islands, Federated States of Micronesia, Palmyra Atoll, Kiribati's Gilbert, Phoenix and Line islands, Solomon Islands, Tuvalu, Samoa, Tonga, Cook Islands, French Polynesia and New Zealand. The Pacific Islands National Wildlife Refuge (NWR) complex is a group of about 50 islands in the Line islands. Wildlife sanctuaries and places of significant biodiversity along these routes include:

• Izembek Lagoon, Alaska. The peninsula lies between the Bering Sea and the Gulf of Alaska: migrants include: Black Brant Goose B. b. nigricans; 150-200,000, nearly all of the Pacific population of Black Brant use this site to moult, fatten up and prepare for the southern migration. About 50,000 remain here for the winter. The number of overwintering geese is increasing with global warming changing migration patterns. Taverner´s Cackling Goose B. h. taverneri, Emperor Goose; 70,000, over half of the world population migrate through Izembek. Steller's Eider; 23,000 birds moult, fatten up and prepare for their southern migration here.

• Hawaiian Islands Chain A string of Central Pacific islands, treated here as stretching from Midway Atoll to the island of Hawaii, or Big Island as it called colloquially.
• Midway Atoll, Pacific. Migatory species include Ruddy Turnstone, Wandering Tattler, Pacific Golden Plover, Bristle-thighed Curlew and Long-billed Dowitcher.
• Kealia Pond, Maui The refuge is a wetland along Kealia Beach in Maalaea Bay in the south west of the island.
• James Campbell NWR, O'ahu. Between the heliport at Turtle Bay and Kahuku.
• Hanalei NWR, Kaua’i. Located south of Princeville on the northern shore. Migratory species include Bristle-thighed Curlew, Pacific Golden-Plover, Northern Shoveler, Northern Pintail and Snow Goose.

• The mudflats of the Suva Peninsular in Fiji has been noted as an Site of National Significance with the southern migration of species including: Wandering Tattler; 1% of the world's population, Short-tailed Shearwater, Cook's Petrel, Ruddy Turnstone, Pacific Golden Plover and Mottled Petrel listed.
  

Pacific Island stopover and breeding sites include one or more of the following routes used by a number of long distance migrants, including the following species; Bar-tailed Godwit, Bristle-thighed Curlew, Wandering Tattler and Pacific Golden-Plover.

• Evidence suggests that there is a migration route for the Pacific Golden-Plover through Japan, Honshu, the Ogasawara (Bonin) Islands, Iwo Islands to the Northern Mariana Islands (NMI) -splitting to either Yap in the western Federated States of Micronesia and ending in either Palau. Or the NMI over the Marshall Islands, Gilbert, Phoenix and Line Islands of Kiribati and on to French Polynesia. Palau also has migrating birds from south Asia and Australasia.

• A second route, used by the Bar-tailed Godwit and Pacific Golden Plover, crosses from the Gulf of Alaska to the Yellow Sea between China and Korea, but further south across the open ocean than in the East Asia - Australasia Flyway discussed earlier.

• From the Yellow Sea, The Bar-tailed Godwit follows a third route that goes broadly via the Solomon Islands to Vanuatu, New Caledonia, Norfolk Island and ending at New Zealand where they overwinter.

• The fourth route goes from Alaska southwest over the central part of the Hawaiian Islands chain, on to the Marshall Islands, where the Bristle-thighed Curlew overwinters, or goes either northwest to Wake Island, or southeast to the the Gilbert Island group of Kiribati. The Bar-tailed Godwit travels further to Vanatu where it joins the second route. There is also evidence that the Pacific Golden Plover uses this route.

• Route five is a route used by Bristle-thighed Curlew starts from Gulf of Alaska, goes southeast to approximately 50°N, 140°W, then almost due south to French Polynesia.

• Austral Migration Austral breeders are birds that breed in the southern hemisphere. Not many migrate from this general warmer part of the world as the climate allows residence all year around. Species using this flyway include;
• Long-tailed Koel Breeds in New Zealand and smaller islands within 100 km of the main islands. Winters to Palau, Carolines and Marshalls through Fiji, Tonga and Samoa to the Cook Islands, Society Islands, Marquesas Islands and the Pitcairn Islands.

Migration hazards

Predation
Human hunters pose a serious hazard to migratory birds. Those channelled over the Mediterranean Islands of Malta and Cyprus, along the North African coastline and in the Sahel south of the Sahara are at risk from mist net traps. In the USA, hunting is having a major negative effect on populations during migration. Along the East Asian-Australasian Flyway illegal hunting is having an adverse affect to populations of migrating birds.

Man-made obstacles
Power lines and wind farms take a large toll of migrating birds along the flyways each migration period. In North America alone, power lines kill up to 64 million birds a year.
Another 7 million are thought to die in collisions with telecommunications towers.
Approximately 234,000 bird deaths a year are caused by wind turbines. These deaths are for all birds. Not just those on migration. However, the majority of these deaths are from migratory birds, especially song birds which migrate at night.

Most deaths occur during take off and landing where these turbines are next to stop-over sites.
Large buildings have caused large numbers of fatalities to migrating birds. In the USA up to one billion deaths occur anually. In one incident, 1000 birds were killed by a combination of weather conditions, heavy migration and bright lights on just one building in Chicago, Illinois in one night.

In 2021 the State of Illinois passed the Bird Safe Buildings Act, which requires bird safety design to be incorporated for all new and renovated state-owned construction projects.
Road traffic collisions cause an estimated 89 million to 340 million bird deaths annually in the USA.

Desertification
An increase in desertification in the Sahel region south of the Sahara makes it more difficult for birds to find food on route. Recent climate change effects show increased periods of drought throughout many areas of the world, including along migration flyways.

Change of farming methods
Increased use of and change in type of pesticides used have had a massive negative impact of insect populations. Intensification of farming methods have caused severe threats to migrating birds, due to loss of habitat.

Accidental or deliberate introduction of invasive species
Islands in particular, have had huge negative impacts to biodiversity levels by the introduction of new species.

• Domestic cats Felis catus, especially feral populations, hunt for all of their food. Evidence suggests they have caused a reduction in population levels and the extinction, or near extinction of about fourteen percent of island species. This biodiversity loss may have a knock on effect for migrating birds, as the biomes affected have been altered. There is evidence that that migrating birds prioritise sleep on arrival after long flights and face a higher risk of predation. The lack, or reduction of local food sources directly, or indirectly attributable to cat predation reduces food available to passage migrants.

• Rodents, especially rats, notably pacific rats Rattus exulans, ship rats R. rattus and brown rats R. norvegicus and mice either directly or indirectly have caused a reduction in both migratory and non-migratory bird species. Direct predation is usually on eggs or chicks. Indirect interaction is usually on the predation of plant species in direct competition to avian species.

• The decision to import, for example, the common brushtail possum, Trichosurus vulpecula to establish a fur trade in New Zealand has had serious consequences for natural ecosystems. Mainly folivorous, possums are also opportunistic omnivores. They eat every part of a plant including; leaves, fruit, buds, flowers and nectar. competing with endemic birds and reptiles. This significantly affects tree and plant growth. Possums have a greater impact on species such as rātā trees, genus Metrosideros or kamahi Pterophylla racemosa, in direct competition to avian species such as Tui, New Zealand Bellbird and New Zealand Kaka. The Chatham Bellbird is now extint. They also occupy tree cavities for nesting in direct competition birds such as Red-crowned Parakeet and Saddlebacks.

• Stoat Mustela erminea as well as the above mentioned possum, also predate bird eggs and chicks, including that of the Kea.

• Feral livestock, particularly pigs, cattle and goats have had a major impact on island biodiversity through habitat loss, nest damage or herbivory in direct competition to endemic species.

Habitat change at stop over sites
Reduction of and change of usage to stop-over sites also cause loss of life to migratory birds.

Effects of Global Warming
With global warming effects being felt in the Arctic Circle, birds, particularly geese are staying longer and even overwintering in greater numbers. Pressure is increasing on the vegation biomass as more geese are feeding on it, the growth period is changing at a slower rate. Migrating geese are increasingly at risk of failing to reach their breeding grounds in the high Arctic as competition for plant biomass becomes more critical.

Natural Barriers to Migration

Bodies of Water

Mediterranean, Gulf of Mexico

Desert

Crossing large areas of desert like the Sahara will require different strategies.

Direct Flight
This strategy is used where a bird flies non-stop over the whole desert.

Oasis to Oasis
This involves migrants flying at night and resting up during the day. Each leg is between oases where water and food are available.

Flight by night, stop-over by day
Using this method, a bird or flock of birds will fly straight across the desert at night. The birds will not eat and use up the reserves they have laid down premigration, or at previous stop-overs on route. The daylight will be used for resting and conserving energy. Sometimes birds will extend their night flight into the day if conditions, such as a good tail wind, allow.

Gradual movement using vegetated areas
The only routes across the Sahara using this method is by following the Nile river, or taking the coastal route along the west African coastline. The Nile is bordered with vegetation. Either swamp, or a narrow band of farmland. The coastline has as broader belt of sparse desert vegetation along it's route.

Migrating birds may use a combination of these methods. The second and third method are often combined where oases have dried up, or the distance between them is too far for one leg.

Mountain Ranges

Mountain ranges create natural barriers to migration that most species of migrating birds need to fly around. There are some species that have evolved that are able to cross these barriers.

• Himalayas. The Bar-headed Goose migrates over this range. Northern Pintail carcasses have been found high in the Himalayas.
• Ural Mountains. The Urals present a major obstacle for up to 2 billion birds heading south from the Russian Arctic that go on to use the Afro-Palearctic Flyway and return in the spring.

Conservation and International Conventions

The Convention on Wetlands (Ramsar), the Convention on Migratory Species (CMS), the International Migratory Bird Treaty Act (IMBTA) and other national and international agreements and conventions have been passed in an attempt to protect wildlife and the areas they utilise. The effectiveness of these conventions and treaties determine the success of conservation projects in the past, present and for the future.

Ramsar

The Convention on Wetlands is an intergovernmental treaty providing the necessary framework for conservation and use of wetlands. It was adopted in Ramsar, Iran in 1971 and finalised in 1975. Nearly 90% of UN member states, have signed up to the convention.

Convention on Migratory Species

The Convention on Migratory Species (CMS] is an environmental treaty belonging to the United Nations. CMS gives a worldwide platform for conservation and sustainability of use for migratory animals and habitats across their range. It provides a legal framework for joint international conservation measures needed across their specific migration range. The convention aids and augments other international organisations, NGOs and their partners in the corporate sector and the media.

International Migratory Bird Treaty Act

The Migratory Bird Treaty Act (MBTA) draws together four conservation treaties between the U.S.A., Canada, Mexico, Japan and Russia. It came to life to sustain the populations of all protected migratory bird species within their range. The (MBTA) forbids the capturing, killing and trafficking of protected migratory bird species without prior authorisation.

Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention)

The Bern Convention is an agreement of the Council of Europe using international law to regulate the protection of plants and animals that live in the wild throughout Europe. It's aim is the conservation of natural habitats and their wild plants and animals.

Convention on Nature Protection and Wildlife Preservation in the Western Hemisphere

This Pan American convention has 19 ratified and a further 3 simple signatories. It allows for the establishment of national parks, national reserves, nature monuments, and strict wilderness reserves for the conservation of plants and animals, specifically for areas used by migratory birds.

Further Reading

• Alerstam, T. 1982. Bird Migration. Cambridge University Press. Cambridge
• Berthold, P. and S. B. Terrill. 1991. Recent Advances in Studies of Bird Migration. Annual Review of Ecology and Systematics . 22: 357-78.
• Berthold, P. 1993. Bird Migration: A General Survey. Oxford University Press. Oxford, New York, and Tokyo.
• Gwinner, E., ed. 1990. Bird Migration Physiology and Ecophysiology . Springer-Verlag. New York, Berlin, and Heidelberg.
• Horton, Kyle G. et al. Phenology of avian migration has shifted at a continental scale. Nature Climate Change Vol 10 Jan 2020 63-68 https://www.nature.com/articles/s41558-019-0648-9
• Klaassen, Marcel et al. Ecophysiology of avian migration in the face of current global hazards. Royal Society London, Philosophical Transactions B Biol Sci. 2012 Jun 19; 367(1596): 1719–1732.
• The Evolution of Bird Migration Adapted from the Handbook of Bird Biology, Third Edition, April 11, 2017 https://www.allaboutbirds.org/news/the-evolution-of-bird-migration/
• William, T. C. and J. M. Williams. 1.Oct 1978. An Oceanic Mass Migration of Land Birds. Scientific American. 239(4): 166-176.
• https://chinadialogue.net/en/nature/how-has-the-ramsar-convention-shaped-chinas-wetland-protection/
• Theunis Piersma et al, The Pacific as the world’s greatest theater of bird migration: Extreme flights spark questions about physiological capabilities, behavior, and the evolution of migratory pathways, Ornithology, Volume 139, Issue 2, 8 April 2022, https://academic.oup.com/auk/article/139/2/ukab086/6523130?login=false
• Victor Pulido et al, Conservation of Charadriiformes on the Peruvian coast, International Wader Studies 8:55-61, 1996, https://sora.unm.edu/sites/default/files/journals/iws/n008/p00055-p00061.pdf
• Simba Chan et al, CMS Technical Report Series No. 22, International Single Species Action Plan for the Conservation of the Black-faced Spoonbill (Platalea minor) Published by BirdLife International and the Secretariat of the Convention on the Conservation of Migratory Species of Wild Animals (CMS)https://eaaflyway.net/wp-content/uploads/2018/01/ts22_black_faced_spoonbill.pdf
• Chang Chin-ju et al, Chiku Industrial Park--A Victim of Fowl Play?, August 1992, Taiwan Panorama, https://www.taiwan-panorama.com/en/Articles/Details?Guid=e9165d01-7988-4091-97be-183eabc60cc9&CatId=10&postname=Chiku+Industrial+Park--+A+Victim+of+Fowl+Play%3F
• Government of Australia, Department of the Environment and Energy, Celebrating Australia's Migratory Waterbirds and their Habitats, Showcasing Australia’s Flyway Site Network, 2017, https://www.dcceew.gov.au/sites/default/files/documents/celebrating-australias-migratory-waterbirds-and-their-habitats.pdf
• PETER LYNGS, Migration and winter ranges of birds in Greenland, An analysis of ringing recoveries, https://rc.ku.dk/publikationer/traekfugleatlas/Greenland_DOFT_2003_1_1.pdf

References

Many thanks to all of our referenced sources and to our members who helped with replies to questions in our forums.

1. Beat about the Bush Trevor Carnaby Jacana Media ISBN 978-1-77009-241-9
2. Bird Life International (2010) Spotlight on flyways. Presented as part of the BirdLife State of the world's birds website. Available from: http://www.birdlife.org/datazone
3. Bird orientation: compensation for wind drift in migrating raptors is age dependent. Thorup et al, The Royal Society, Biology Letters
4. CMS_Flyways_Reviews_Web.pdf
5. Der Falke Journal für Vogelbeobachter Bird mgration - 23.2014.pdf
6. Drift migration - Wikipedia, the free encyclopedia, Kasper Thorup, Thomas Alerstam, Mikael Hake, Nils Kjellén (2003).
7. Flyways.us
8. Gilroy, James J.; Lees, Alexander C. (September 2003). "Vagrancy theories: are autumn vagrants really reverse migrants?" (PDF). British Birds 96: 427–438.
9. Lehigh Earth Observatory
10. Migration Hotspots Tim Harris Bloomsbury, ISBN: 9781408171172
11. Migration in South America: an overview of the austral system Published online by Cambridge University Press: 11 May 2010 R. Terry Chesser
12. Peter Weaver's Birdwatcher's Dictionary Copyright © 1981 by Peter Weaver
13. Rare birds in Britain and Ireland a photographic record. London: Collins. p. 192. ISBN 0002199769.
14. Proc. Royal Soc. London B 270 (Suppl 1): S8–S11. doi:10.1098/rsbl.2003.0014. PMC 1698035. PMID 12952622.
15. Spring Predictability and Leap-Frog Migration Alerstam et al Ornis Scandinavica (Scandinavian Journal of Ornithology) Vol. 11, No. 3 (Dec., 1980), pp. 196-200 (5 pages) Published By: Wiley
16. Reverse migration (birds) - Wikipedia, the free encyclopedia, • #Vinicombe, Keith; David Cottridge (1996).
17. The Cornell Lab of Ornithology All About Birds : Migration
18. US Fish and Wildlife Service
19. See https://ebird.org/news/flywaypaper/
20. F. A. La Sorte, D. Fink, W. M. Hochachka, A. Farnsworth, A. D. Rodewald, K. V. Rosenberg, B. L. Sullivan, D. W. Winkler, C. Wood, and Kelling, S. (2014). The role of atmospheric conditions in the seasonal dynamics of North American migration flyways. Journal of Biogeography 41(9): 1685-1696. https://doi.org/10.1111/jbi.12328
21. Midway's albatross population stable, Honolulu Advertiser, December 27, 2016
22. https://en.wikipedia.org/wiki/Midway_Atoll Wikipedia Midway Atoll, Environment
23. https://friendsofmidway.org/explore/wildlife-plants/birds/migratory-birds/ Friends of Midway Atoll, migratory species
24. https://migration.pwnet.org/pdf/Flyways.pdf
25. https://www.fws.gov/refuge/hanalei Hanalei National Wildlife Refuge
26. https://www.eaaflyway.net/task-force-on-illegal-hunting-taking-and-trade-of-migratory-waterbirds/
27. H. Biebach et al. Strategies of Trans-Sahara Migrants https://link.springer.com/chapter/10.1007/978-3-642-74542-3_23
28. https://www.audubon.org/news/more-1000-birds-collided-single-chicago-building-one-night
29. https://www.theguardian.com/environment/2019/apr/07/how-many-birds-killed-by-skyscrapers-american-cities-report
30. https://www.fws.gov/story/threats-birds-collisions-road-vehicles
31. https://www.wetlandtrust.org.nz/wp-content/uploads/2018/12/Ramsar_in_the_Pacific_V_Jungblut.pdf
32. https://rsis.ramsar.org/ris/244
33. https://www.birdscanada.org/conserve-birds/fraser-river-estuary
34. https://www.birdscanada.org/new-paper-underlines-importance-of-bcs-fraser-delta-to-birds
35. https://whsrn.org/whsrn_sites/copper-river-delta/
36. https://whsrn.org/linking-sites/pacific/copper-river-delta/
37. https://www.adfg.alaska.gov/static/lands/protectedareas/_land_status_maps/copperriverdeltals.pdf
38. R. A. Stillman et al,Predicting impacts of food competition, climate, and disturbance on a long-distance migratory herbivore March 2021 https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.3405
39. Makereta Komai, The Wandering Tattler – a migratory sea-bird of importance to Fiji, December 2020 https://pasifika.news/2020/12/the-wandering-tattler-a-migratory-sea-bird-of-importance-to-fiji/
40. D. W. Stinson et al, Pacific Science 1997, vol.51, no.3: 314-327, Migrant Land Birds and Water Birds in the Mariana Islands! https://core.ac.uk/download/pdf/5095274.pdf
41. Alexandra Mae Jones, Bird reportedly flies 12,000 km non-stop from Alaska to New Zealand, breaking record, October 2020, https://www.ctvnews.ca/sci-tech/bird-reportedly-flies-12-000-km-non-stop-from-alaska-to-new-zealand-breaking-record-1.5147565?cache=yes%3Fclipid%3D104056
42. https://www.doc.govt.nz/nature/pests-and-threats/animal-pests/possums/
43. https://www.doc.govt.nz/news/media-releases/2010/possums-eat-kea/
44. David R. Towns et al, November 2004 Have the Harmful Effects of_Introduced Rats on Islands been Exaggerated? https://www.researchgate.net/publication/225530166
45. Gerard Gray et al, MONTSERRAT CENTRE HILLS FERAL LIVESTOCK ACTION PLAN, https://www.nature.com/articles/ncomms2380
46. Félix M. Medina et al, A global review of the impacts of invasive cats on island endangered vertebrates, June 2011, https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2011.02464.x
47. Scott R. Loss et al, The impact of free-ranging domestic cats on wildlife of the United States, December 2013, https://www.nature.com/articles/ncomms2380
48. Theunis Piersma et al, The Pacific as the world’s greatest theater of bird migration: Extreme flights spark questions about physiological capabilities, behavior, and the evolution of migratory pathways, Ornithology, Volume 139, Issue 2, 8 April 2022, https://academic.oup.com/auk/article/139/2/ukab086/6523130?login=false
49. https://whc.unesco.org/en/list/1362/
50. https://ogasawara-info.jp/wp-content/uploads/2023/02/calender_birds.pdf
51. Eugene P. Odum and Clyde E. Connell, Lipid Levels in Migrating Birds, Science, 18 May 1956, Science Vol 123, Issue 3203 pp. 892-894 DOI: 10.1126/science.123.3203.892.b,https://www.science.org/doi/10.1126/science.123.3203.892.b
52. Charles Post, Shorebirds in winter mode, Swarovski Optik, https://www.swarovskioptik.com/us/en/birding/stories/shorebirds-in-winter-mode
53. https://en.wikipedia.org/wiki/Point_Reyes_National_Seashore,_California
54. https://www.whitehawkbirding.com/bird-migration-in-panama/
55. H. Blokpoel et al, Field Observations of the Biology of Common Terns and Elegant Terns Wintering in Peru, Colonial Waterbirds, Vol. 12, No. 1 (1989), pp. 90-97, https://www.jstor.org/stable/1521316
56. https://www.audubon.org/conservation/americas/chile
57. N.N. Gerasimov & Y.N. Gerasimov, The international significance of wetland habitats in the lower Moroshechnaya river (West Kamchatka, Russia) for waders, 1998, https://sora.unm.edu/sites/default/files/journals/iws/n010/p00237-p00242.pdf
58. CHI-YEUNG CHOI et al, The importance of Yalu Jiang coastal wetland in the north Yellow Sea to Bar-tailed Godwits Limosa lapponica and Great Knots Calidris tenuirostris during northward migration, 14 August 2014, https://www.cambridge.org/core/journals/bird-conservation-international/article/importance-of-yalu-jiang-coastal-wetland-in-the-north-yellow-sea-to-bartailed-godwits-limosa-lapponica-and-great-knots-calidris-tenuirostris-during-northward-migration/229FCD53734E70C7D3D4A6A05B17D620
59. Jason Loghry et al, Dandong Yalu Jiang Estuary Wetland National Nature Reserve, China, 22.03.2017, https://www.birdskoreablog.org/?p=19237
60. Simba Chan et al, CMS Technical Report Series No. 22, International Single Species Action Plan for the Conservation of the Black-faced Spoonbill (Platalea minor) Published by BirdLife International and the Secretariat of the Convention on the Conservation of Migratory Species of Wild Animals (CMS)https://eaaflyway.net/wp-content/uploads/2018/01/ts22_black_faced_spoonbill.pdf
61. Martin Williams, Case of the Disappearing Spoonbills, Apr 01, 2003, The National Wildlife Federation,https://www.nwf.org/Magazines/National-Wildlife/2003/Case-of-the-Disappearing-Spoonbills
62. Ramsar, The Convention on Wetlands, https://www.ramsar.org/
63. Convention on the Conservation of Migratory Species of Wild Animals, CMS, https://www.cms.int/en/legalinstrument/cms
64. Migratory Bird Treaty Act 1918, US fish and wildlife Service, https://www.fws.gov/law/migratory-bird-treaty-act-1918
65. Bern Convention, Council of Europe, http://conventions.coe.int/treaty/en/Treaties/Html/104.htm
66. Mai Po marshes and Inner Deep Bay, Ramsar Sites Information Service, https://rsis.ramsar.org/ris/750
67. Deep Bay Wetlands, WWF, https://www.wwf.org.hk/en/wetlands/deep-bay/
68. https://news.mongabay.com/2017/11/indonesians-race-to-save-their-disappearing-lakes-before-its-too-late/
69. https://www.thejakartapost.com/news/2016/09/21/festival-held-to-conserve-migratory-birds-at-limboto-lake.html
70. Ding Li Yong et al, The State of Migratory Landbirds in the East Asian Flyway: Distributions, Threats, and Conservation Needs, 13 April 2021, Frontiers in Ecology and Evolution, Sec. Conservation and Restoration Ecology Volume 9 - 2021 https://www.frontiersin.org/articles/10.3389/fevo.2021.613172/full
71. UNTC, https://treaties.un.org/Pages/showDetails.aspx?objid=0800000280150233&clang=_en
72. Convention on Nature Protection and Wildlife Preservation in the Western Hemisphere, U.S. Fish & Wildlife Service, https://www.fws.gov/law/convention-nature-protection-and-wildlife-preservation-western-hemisphere
73. Coastal Conservation and Education Foundation (CCEF), OneOcean, http://oneocean.org/ambassadors/migratory_birds/other_ramsar_sites_in_the_philippines.html
74. Partnership for the East Asian Australasian Flyway, https://www.eaaflyway.net/olango-island-wildlife-sanctuary/
75. Scotty's Action Sports Network, https://www.divescotty.com/island-tours/bird-sanctuary-olango.php
76. Nilo Arribas, Jr., A SHORT GUIDE TO BIRDING IN OLANGO ISLAND WILDLIFE SANCTUARY (OIWS), November 10, 2011, eBON, Wild Bird Club of the Philipinnes,https://ebonph.wordpress.com/2011/11/10/birding-in-olango-wildlife-sanctuary/
77. https://www.ramsar.org/country-profile/philippines
78. https://pngbiodiversity.org/wp-content/uploads/2022/06/Tonda_METT_24Feb_17_Low_res.pdf
79. https://www.ramsar.org/country-profile/papua-new-guinea
80. http://datazone.birdlife.org/userfiles/file/sowb/flyways/8_EastAsia_Australasia_NEW.pdf
81. Birdforum.net members comments/various fora https://www.birdforum.net/forums
82. Birdforum/Opus https://www.birdforum.net/opus/Welcome
83. eBird Range maps, https://ebird.org/species
84. Macaulay Library, https://www.macaulaylibrary.org
85. Audubon Guide to North American Birds, https://www.audubon.org/field-guide/bird/
86. Bylot Island Migratory Bird Sanctuary, Government of Canada,https://www.canada.ca/en/environment-climate-change/services/migratory-bird-sanctuaries/locations/bylot-island.html
87. Icelandic Institute of Natural History, 2023, https://www.ni.is/en/fauna/birds/important-bird-areas
88. Lennart Karlsson et al, Wings over Falsterbo, ISBN 91-86572-37-7, ISSN 0347-9609, Printed by Wallin & Dalholm Boktryckeri AB,Lund,2004.
89. Romke Kleefstra et al, TRENDS OF MIGRATORY AND WINTERING WATERBIRDS IN THE WADDEN SEA 1987/1988-2019/2020, Common Wadden Sea Secretariat (CWSS), Wilhelmshaven, Germany, Expert Group Migratory Birds (EG MB), 2022, https://www.waddensea-worldheritage.org/sites/default/files/2022_Ecosystem41_MigratoryBirds.pdf
90. Wild Andalucia, 20/03/2020 http://www.wildandalucia.com/bird-migration-strait-of-gibraltar/
91. Fundacion Migres, https://www.fundacionmigres.org/en/programa-migres/
92. https://www.birdwatchingsagres.com/en/natureza/10/sagres-migration-hotspot

• List of references

Recommended Citation

• BirdForum Opus contributors. (2024) Migration. In: BirdForum, the forum for wild birds and birding. Retrieved 29 April 2024 from https://www.birdforum.net/opus/Migration