The study of bird migration is been undertaken in many countries through study of movements of marked birds and field surveys and studies. The following section provides a brief introduction to the different tools available. Detailed information on these techniques that is widely covered in manuals and websites; and to which a few links are provided.

Bird Marking

Tools to study bird migration, particularly migratory waterbirds, include marking of birds with temporary plumage dyes, metal and colour marks of different types to the use of sophisticated electronic devices that can beam information on the movement of birds.

Metal rings/bands

the first century of work to identify the migratory routes of birds has been largely undertaken by a number of national schemes and research programmes in many countries through the use of metal rings (bands) on which is inscribed address details of the scheme and a unique number. A ring is affixed to a leg of a bird. Recording movements of such a marked bird has required having the bird in the hand to read the information inscribed on the ring (either through its capture and release, or when it is found dead, or by shooting it).

Sustained efforts by these research groups have helped to build up a general picture of migration of many species and a very detailed overview for a few species. Such work has been published in many different journals and sources in a variety of languages.

An early foundation to our knowledge on the migratory movements of Asian birds, particularly in East, South and Southeast Asia was the successful Migratory Animal Pathological Survey (MAPS) programme undertaken between 1963-1971 that involved teams from several countries across the region marking more than a million birds of over 1,000 species. The success of this programme provided encouragement for a number of national schemes and groups to continue and to generate valuable information.

Colour marking

In the last few decades, the study of migration has been greatly aided by the use of bright colour marks that enables observation of the bird in the field with a telescope or binoculars without the need to capture the birds and through which it is possible to either identify individuals or marking locations based on the colour or combination of colours used. A range of colour marking techniques have been developed and successfully used for a variety of species by a wide range of groups in the region. The use of colour flags have transformed our understanding of the migration routes of shorebirds in the major flyways.

In the East Asian - Australasian Flyway, migration studies by colour marking have been lead by the Australasian Wader Studies Group. Information on colour-marking of shorebirds is available on the Australasian Wader Studies Group website. Colour neck collars and leg bands have been very useful to identify the migration routes of swans, geese and cranes, work undertaken by the Wild Bird Society of Japan, Yamashina Institute of Ornithology, Japan Association for Wild Geese Protection and National Bird Banding Centre of China and others.

Transmitters

The use of electronic means to study migration was first by the use of short-range, very high frequency (VHF) radio transmitters in the 1960s. In the last two decades, the availability of light and reliable satellite transmitter terminals (PTTs) that can be mounted on the birds or implanted under their skin and which can beam data via satellite to research groups have been effectively used to collect very precise information on the exact locations and habitats used by the birds on their migration cycle; work that has also assisted in identifying inaccessible sites and in prioritizing sites for conservation. Since 2000, the use global positioning system (GPS) transmitters has helped to increase the resolution of location of birds.

In the Asia-Pacific region, satellite transmitters have been used for cranes, swans, geese, pelicans, loons and shorebirds by a wide range of institutions including the US Fish and Wildlife Service and Geological Service, Wild Bird Society of Japan, Yamashina Institute of Ornithology, International Crane Foundation and others.

Geolocators

Most recently, the use of geolocators, which are attached or implanted in the birds is being used to study the migratory routes. Geolocators use day length as an indicator for latitude and longitude and a constaint is that these devices need to be retrieved to download the information. They have been used so far on a number of species including geese, penguins, albatross, and other seabirds, ducks, shags and seals. Being so small, they can be attached on leg rings thus avoiding problems associated with platform gluing and the dangers of harnesses. More information is available here

Field Monitoring

Surveys and regular monitoring of the birds in the field at different times of the year have helped to improve our understanding of the breeding areas, timing, routes and staging, moulting and non-breeding (wintering) sites of many species. The International Breeding Conditions Survey on Arctic Birds (ABBCS) aims at collating information on environmental conditions on breeding grounds of Arctic nesting birds in a regularly updated database. This project is a joint venture of International Wader Study Group and Wetlands International's Goose and Swan Specialist Groups.

The International Waterbird Census programme coordinated by Wetlands International has provided an important framework to collect and disseminate information on the distribution and abundance of waterbird species in the non-breeding grounds.