A Journey Fraught with Dangers
The migration route of a disappearing speacies
Turtle Doves are disappearing from our landscape. Since the 1970s, their population has plummeted by more than 85% in West Europe: the Netherlands has seen a 97% population decline. The decline of this migratory dove is a complex and international problem – habitat loss in both wintering and breeding areas, unsustainable (legal) hunting, illegal trapping and killing, and disease are all contributors to their decline.
If we can establish which countries and regions Dutch Turtle Doves pass through and winter in, the Netherlands will be able to contribute to the international conservation effort for the species. This data can be used to apply pressure to Governments regarding the hunting policies of individual countries, or the development and maintenance of suitable Turtle Dove habitat in wintering grounds or in vulnerable migratory bottleneck and stop-over areas.
In order to learn more about the migration of Dutch Turtle Doves, two doves will be equipped with satellite trackers (“PTTs”) by means of a small “backpack” harness. Modern satellite technology will provide detailed information regarding the dove’s location, allowing us to follow each dove’s progress online. The trackers selected for this project are the lightest available, weighing just 2g, so as to cause as little inconvenience to the dove as possible.
PTT - A satellite transmitter from Microwave Telemetry
What happened to Jos and Jozien?
During the course of this project, both Jos and Jozien’s transmitters stopped working. Contact was lost with Jozien after just 3 weeks of tracking, while Jos was followed for 14 ½ months before contact was lost.
The exact cause and circumstances surrounding their disappearances are unknown, but there are a few conclusions that can be drawn. In both cases, contact was lost with them on their Dutch breeding grounds, ruling out the possibility of hunting as a cause of death. Additionally, if one of them had become injured or ill, there would most likely be a visible decline in battery power of their tracker (PTT); a dove spending increasing time sheltering in the scrub or undergrowth would limit the recharging of the solar powered battery. As we did not see a decline in battery power, this leaves the most likely cause of Jos and Jozien’s disappearance as being either predation, or else a technical issue, such as a broken antenna. Either of these scenarios would result in the sudden cease in data transmission that we experienced.
This research is financed by Vogelbescherming Nederland, BirdLife International and Het Zeeuwse Landschap
It is conducted with the support and advice from SOVON Vogelonderzoek Nederland, Rijks Universiteit Groningen and the Justus Liebig University Giessen (Germany)