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Spotlight on flyways
  
Bar-tailed Godwit, © Sue Tranter/rspb-images.com
Migration is one of the most fascinating aspects of the avian world. Twice a year, billions of birds migrate vast distances across the globe. Many species migrate along broadly similar, well-established routes known as flyways. Unfortunately, many of the world’s migratory species are in decline, assailed by multiple threats, including habitat loss and degradation, illegal and unsustainable hunting, infrastructure development, climate change and disease. The conservation of migratory birds depends on international collaboration and a coordinated conservation response along their flyways.

Birds are arguably the most mobile creatures on Earth, often undertaking truly epic journeys (Migrating birds know no boundaries, The Bar-tailed Godwit undertakes one of the avian world’s most extraordinary migratory journeys).The area covered by a migrant over the course of its annual cycle, encompassing breeding and non-breeding grounds and the connecting migration route, is known as a flyway (The flyways concept can help coordinate global efforts to conserve migratory birds).

Unfortunately, many of the world’s migratory birds are in decline (North American monitoring schemes are revealing declines in migratory species, Palearctic–African migratory birds have suffered substantial declines). Undertaking such dramatic journeys can push birds to the limit of their endurance as they are reliant on favourable weather conditions and the presence of adequate food resources at multiple sites throughout their migration. The most serious threat is the loss and modification of natural habitats (Large dams threaten one of Africa’s most important wetland ecosystems). Migratory waterbirds in Asia are particularly affected, with many of the region’s remaining wetlands threatened through land reclamation for agriculture and development (Waterbirds are showing widespread declines, particularly in Asia). Some sites are critical: for example, Delaware Bay, USA, where the unsustainable exploitation of horseshoe crab has contributed to the collapse of the Red Knot Calidris canutus population (Commercial shellfisheries can negatively impact migratory waterbirds).

Another significant threat is widespread hunting. In some parts of the world migratory birds are hunted for food or as a culinary delicacy, elsewhere it is purely recreational (Illegal trade in European songbirds for food). In addition to direct mortality, hunting also poses a threat through disturbance and pollution with thousands of tonnes of highly toxic lead pellets discharged around the world annually (Lead ammunition continues to build up in the environment, poisoning birds). Larger species, such as storks and raptors, face the additional risk of collision with man-made structures such as powerlines and wind turbines (Collisions and electrocutions pose real threats for young and migrating birds, Powerlines pose a threat to Italian birds, Offshore wind farms are impacting seabirds and migrating passerines).

Over the coming decades, climate change is anticipated to have a dramatic impact on the distribution and survival of migratory birds (In the Arctic tundra, climate change will cause dramatic losses in waterbird breeding habitat). Climate change may also affect some species by uncoupling the timing of resource availability from the timing of migration. For example, whilst the brood-parasitic Common Cuckoo Cuculus canorus has advanced its migration only modestly, many of its host species are now arriving at the breeding grounds considerably earlier. Migrants typically have smaller brains and are less flexible in behaviour and resource use than resident species. Consequently, they may be less able to adapt to changes in climate than non-migratory species (Palearctic–African migratory birds have suffered substantial declines).

Migratory waterbirds are also prone to periodic outbreaks of infectious disease at sites where they congregate Avian botulism is perhaps the most important disease affecting migratory birds worldwide. In 2002–2003, an outbreak in Taiwan killed more than 7% of the global population of the threatened Black-faced Spoonbill Platalea minor (Avian diseases are spreading to impact hitherto unaffected populations).

In the face of such a diverse array of threats, the conservation of migratory birds depends on international collaboration and a coordinated response across entire flyways (International agreements can be used to make transboundary ecological networks a reality). The Convention on Migratory Species (CMS), stresses the need for coherent ecological networks of transboundary protected areas. Important Bird Areas (IBAs) can make a crucial contribution to identifying critical sites for migrants and in many regions the inventory has been used as a ‘shadow list’ to identify potential Ramsar sites (Wetlands of International Importance) (Important Bird Areas for congregatory species: Eurasian Spoonbill).

The effective conservation of migratory birds requires a coordinated response on a global scale. BirdLife is ideally placed to deliver this, with national partners throughout all major flyways. For example, BirdLife’s Sustainable Hunting Project (2004-2007) brought together national governments, hunting groups and conservation organisations from across North Africa and the Middle East to tackle the problem of migratory bird hunting in the Mediterranean (Towards sustainable hunting in the Middle East).

The Wings over Wetlands (WOW) initiative was a flyway-scale approach to the conservation of migratory waterbirds involving collaboration between BirdLife, Wetlands International, the Ramsar Convention on Wetlands, the United Nations Environment Programme’s World Conservation Monitoring Centre (UNEP-WCMC), and a range of local partners along the African-Eurasian Flyways. The Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) is the largest multilateral Agreement concluded under the CMS. The WOW project, which ran from 2006 to 2010, aimed to support the implementation of the agreement by identifying critical sites for migratory waterbirds within the AEWA region (A network of critical sites for migratory waterbirds is being identified across Africa and Eurasia). As part of the WOW initiative, a number of conservation projects were implemented by national BirdLife Partners (Community led wetland restoration in Nigeria, Collaboration between conservationists and local religious leaders can safeguard IBAs). For example, BirdLife’s Hungarian Partner (MME) introduced a ‘nature friendly’ fish-farming strategy; helping to safeguard an internationally important waterbird breeding site and staging ground (‘Nature friendly’ fish-farming techniques in Hungary bring economic benefits).

In order to effectively target conservation action, it is essential to understand the distribution and ecology of migratory species, and especially the migration routes that they follow. Until recently, the African wintering grounds of the Aquatic Warbler Acrocephalus paludicola were unknown, hampering efforts to conserve the species. However, in 2007, following five years of investigation, a research team from BirdLife and the RSPB (BirdLife Partner in the UK) finally succeeded in tracing the birds to an area of northwest Senegal (Stable isotopes analysis reveals the wintering grounds of the Aquatic Warbler). Elsewhere, BirdLife Partners are targeting research at some of the world’s most imperilled migratory species in order to better understand their conservation needs (The wintering grounds of Northern Bald Ibis in Syria have been discovered using satellite tracking, Investigating the causes of Sociable Lapwing declines).

To access these and other case studies on flyways, please click on the following links.

Flyway factsheets

The following factsheets present information on eight major global flyways.

Pacific Americas Flyway   Central Americas Flyway   Atlantic Americas Flyway   East Atlantic Flyway

Pacific Americas Flyway

 

Central American Flyway

 

Atlantic Americas Factsheet

 

East Atlantic Factsheet

     
Mediterranean & Black Sea Flyway East Asia & East Africa Flyway Central Asia Flyway East Asia & Australasia Flyway

Mediterranean & Black Sea Flyway

 East Asia & East Africa Flyway  Central Asia Flyway  East Asia & Australasia Flyway

Links
African-Eurasian Migratory Waterbird Agreement (AEWA)
The Critical Site Network Tool
The Convention on Migratory Species
World Migratory Bird Day 2011
Wings over Wetlands

Compiled 2010

Recommended citation
BirdLife 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