BirdEyes launches five-year study into the complexity of chick survival
How do black-tailed godwit chicks respond to predators? What do they need as they grow up? And when they are just able to fly? Can we entice young godwits to return to an area with sufficient food? These and other questions form the basis of new scientific research by BirdEyes, in collaboration with the University of Groningen, the University of Amsterdam, Vogelpark Avifauna, Bureau Altenburg & Wymenga Ecologisch Onderzoek, and the Bond Friese VogelWachten. The results of the research, together with a robust package of measures from the Ministry of LVVN, will be used to tackle the decline of the Dutch godwit population.
Twenty years of black-tailed godwit research
The new research builds on the knowledge gained from more than twenty years of fieldwork in Súdwest-Fryslân. The Grutto Landschap Project identified a wide range of factors, from vegetation structure and soil moisture to insect availability and predators. Two factors appear to have a strong influence on the survival chances of chicks: food supply and predation. Project leader Jos Hooijmeijer: “We have been keeping track of the black-tailed godwit population for more than 20 years. This shows that improving chick survival is the key to reversing the decline. Black-tailed godwit chicks are most vulnerable in the first 40 days of their lives. Among other things, they depend on sufficient and accessible food. If all the insects are too high up in the vegetation, a chick cannot reach them. In open and varied vegetation, a chick can move around easily and find cover when danger threatens.”
Collaboration with Avifauna
For the new study, BirdEyes is collaborating with Avifauna, an organization with extensive experience in hatching and caring for young birds, including endangered species. Avifauna incubates black-tailed godwit eggs in a constant, closely regulated environment and monitors the chicks during their first days of life until they are strong enough to stay in fenced test fields during the day. Thanks to this collaboration, researchers can carefully observe early growth stages, which is hardly possible in the wild. They are also learning more about the limits and possibilities of headstarting: releasing birds that have been raised in captivity. This method has been used in the UK, among other places, as a policy measure to strengthen the black-tailed godwit population.
Food supply and growth
Over the next two years, expert volunteers from the Bond Friese VogelWachten (BFVW) will collect 160 eggs per year from lapwing nests with a low success rate, for example in areas with high nest predation or intensive land use, such as corn fields. Avifauna will hatch the eggs. The researchers will weigh the chicks daily. They will also map the insect population in each test field. The chicks’ droppings will then reveal what prey they have actually eaten. Predators are excluded from this part of the study. Surveillance and fencing ensure a safe environment, so that food quality and growth can be assessed independently of predation risks.
photos: Astrid Kant
Wild chicks
Wild chicks are also being studied—in their natural habitat, where predators pose a constant threat. As soon as the chicks hatch, they are fitted with a small radio transmitter. This enables researchers to monitor the chicks’ condition and determine causes of death, with the help of drone experts from the BFVW. Hooijmeijer: “Are the black-tailed godwit chicks maintaining their weight? If so, it is more likely that their survival depends heavily on predation risks.” It will also become clear whether the chicks respond to the presence of predators. Just before the young godwits are able to fly, the radio transmitters will be replaced by a satellite transmitter. Hooijmeijer: “We are going to look at how both groups of chicks behave after fledging, which areas they prefer before leaving the Netherlands, and whether they return to suitable habitats.”
Funding and impact
The Ministry of Agriculture, Fisheries, Food Security, and Nature (LVVN) is funding the research. The results are directly linked to other measures taken by LVVN to increase the black-tailed godwit population in the Netherlands. Examples include strengthening agricultural nature and landscape management in the most important black-tailed godwit areas, optimizing meadow bird and water management, and adding conservation targets for the black-tailed godwit to the existing 25 bird directive areas. This creates synergy between management, knowledge, and fieldwork. BirdEyes’ research provides a crucial piece of the puzzle: an accurate picture of the early life stage of black-tailed godwit chicks.
For more information about the study, please contact E.W. Drijver: esther@birdeyes.org
