Northern Bald Ibis: research projects
Due to this high breeding success the idea about releasing captive born birds has been discussed intensely. Many studies on the Northern Bald Ibis in captivity and in the field have shown that the NBI is a highly social evaluated and sensitive bird species and has only a short period of learning when they are young. As the release untrained adult and young birds failed only evolving a new releasing method which takes the complicate social structure and the short learning period of this bird species into concern will probably lead to a self sustaining population.
Since 1996 4 research projects are working on release methods with different priorities. So far it is possible to establish a sedentary, free flying, self sustaining Northern Bald Ibis colony.
The Konrad Lorenz Forschungsstelle NBI population was established in 1997. The initial group was hand raised and guided by their human parents. The birds are left free flying and are foraging at the meadows nearby the research station and village of Gruenau, Austria. During the first three years quite a number of juvenile were lost due to juvenile dispersal short after fledging. The following years the birds were kept in an aviary during this critical period. After 3 further years the birds had built up a sedentary tradition and could be left free flying the whole year without further losses due to migratory or dispersal behaviour. The offspring of the colony are continuing this sedentary tradition.
The colony started to breed in 2000. All together the colony numbers about 40 birds (2008). Over the years the hands on management of the group has been gradually decreased and due to natural reproduction, the proportion of hand raised individuals in the group has decreased to approximately 20 %.
Since 1997 a number of research projects have been conducted including topics such as social learning, foraging, social development and socialization, cooperation of partners over raising offspring and the functions of sexual ornaments and their tradeoffs with immunity (patches of red skin). The plan for the next years is to split the colony. To do this young parent -reared birds will be transferred to another location and kept there free flying. The idea is to test how the transferred parent-reared birds will cope with this new situation.
The waldrappteam.at project started in 2002. The project is working with two major topics:
- teaching NBI a migration tradition from the breeding area to an appropriate wintering area and monitor the spatio-temporal pattern of the birds when they become independent after their arrival in the winter area.
- conducting research on migration disposition and migration physiology. The physiological data will permit the evaluation of human-led migration as a method for bird conservation and reintroduction.
Guided by flying motor trikes, flown by people on whom the hand-reared birds had imprinted, the juveniles “migrate” to Italy. The first trip started in 2004. Since then each year about 8-10 juveniles have been led to the wintering area. These young birds, most of them carrying a radio transmitter, stay there over winter in the protected area of Grosetto and are observed throughout the whole winter. In spring the supplementary feeding at this site is stopped, and the birds are left to fend for themselves.
In May 2005 for the first time birds migrated north, however they did not reach the area in Austria where they had been reared. In spring 2006 again 5 birds left Grossetto and 2 found their way up north to Carinthia, in 2007 3 birds flew north to Austria (Styria). In March 2008 6 of the adult birds (born in 2004) headed northwards and flew up to Friaul, North Italy. There they were captured and taken into an aviary where one pair started to breed. Two chicks hatched and after these fledged all the birds were released. In September they left Friaul heading south and arrived after two days in their wintering area in Grosetto. This has shown that the NBI can learn a migration route.
Additionally the Waldrappteam.at started in 2008 a research project on migration physiology in cooperation with the University of Vienna. This project offers a unique chance to closely monitor migrating birds and to take samples (blood/faeces adrenalin, metabolism, fat, body mass) from birds undertaking both fatiguing and non-strenuous flights, to document extremes in the analyses of physiological parameters and flight duration.
As part of this project a study was carried out to see whether there would be advantages to rearing NBI with cattle egret (Bubulcus ibis). No negative impact between the two species, no imprinting on each other and no significant behaviour differences between the groups of ibis (reared with and without cattle egrets) occurred, however both groups acted as single ones when released. Therefore cattle egrets were not used in 2006 due to the fact that no major benefit was observed with this methodology.
As a further technique a smaller group of young parent-reared birds were incorporated into the group of the hand-reared birds. This happened when the birds were kept in the aviary during the dispersal period. Then the birds were released to fly freely in the release area of El Retin. So far the hand reared birds have survived best. In 2008 one pair bred successfully in a cliff close to the study area.
The project “Bechar el Kheir” was founded in 1999 due to the intention of the Forest Ministry (Haut Commissariat aux Eaux et Forets et a la Lutte Contre la desertification) to evaluate whether the possibility of a potential reintroduction of the NBI in their former range in the Atlas region of Morocco, accompanied by socio economic and educational activities. was possible.
A breeding station with two aviaries was erected built and birds were brought to breed there. Breeding started in 2001 however obviously too severe winters lowered the survival of the offspring. Changes in husbandry led to good breeding success in 2005/2006.
For more and detailed information see IAGNBI conservation report 2007 (2,3MB)