Download the map of the Migration of the Purple Herons

Purple Herons with satellite transmitters
Vogelbescherming Nederland and Bureau Waardenburg cooperatively started in July 2007 with equipping Purple Herons with satellite transmitters. Since 2008 also Wetlands International is involved in the project by giving support and awareness raising for the conservation of the species. The aim is to get information on habitat use and feeding range in the breeding season and to get insight in migration routes, wintering sites and stopover sites. African wintering areas are imperfectly known as it remains unclear if herons migrate within Africa during the northern winter. For wetland protection along the flyway, information is necessary to get a picture of relevant wetlands. The project will also strengthen the international nature conservation network and will be used to involve the general public in bird migration and wetland conservation issues.

For migration routes of the individual tagged birds see the special Purple Heron page of Vogelbescherming Nederland and the 'Follow the Bird!" page on the website of Wetlands International.

Cartching Herons
Bureau Waardenburg developed a nest trap for catching adults. Additionally one adult was captured in cooperation with “Aquila Services” by the use of canon nets at a feeding site. The nest trap was based on an egret trap developed by Jewell & Bacroft 1991, but modified for specific use in reedbeds and for Purple Herons which are larger than Little Egrets. The trap worked succesfully and all adult birds continued breeding after handling and the majority was succesful in raising young.

Satellite techniques developed for herons
Very little experience is available for adjusting satellite transmitters on herons. Tour du Valat were the first to adjust transmitters on Juvenile Purple Herons. The birds/transmitters were lost in North Africa (E. Jourdain pers. comm.). Herons do have a specific elongated body shape and can take large prey. For this reason, tests in the Rotterdam Zoo and bird rehabilatation centre De Bonte Piet were organised with different types of harnesses and different materials on Little Egrets and juvenile Grey Herons respectively. Most adults were equipped with soft but strong leather harnesses and for both two juveniles teflon was used.

Transmitters used for herons
One adult and both juveniles were equipped with standard satellite transmitters (PTTs, Platform Transmitter Terminals) including harness the mass is 20-25 g. Microwave Telemetry provided the transmitters. The mass is less than 2.75% of the Purple Heron body mass (average in literature 960-1100 gram). All captured bird weighed more than 1100 gram. For four adults GPS/PTT transmitters were used. These transmitters are heavier (45 gram including harness, which is 4.1-4.6% of the body mass), but provide accurate data on habitat use. For an extensive overview of methods and transmitter types see http://www.microwavetelemetry.com and for information regarding the satellite receiving technology the site of Argos.

Information and contact
Bureau Waardenburg provides services for studies on birds and other wildlife and can be contacted for information on heron ecology, the methods and techniques used for transmitters and harnesses. For more information please contact Jan van der Winden or Martin Poot. For information on Purple Heron protection and conservation contact Vogelbescherming Nederland and Wetlands International.