Guest blog by Dr Jenny Dunn, Conservation Scientist, RSPB Centre for Conservation Science
A paper, 'Post-fledging habitat selection in a rapidly declining farmland bird, the European Turtle Dove Streptopelia turtur' published 20th April 2016 in the journal Bird Conservation International, describes the results of work carried out by a team of RSPB scientists to discover what happens to turtle doves once they leave the nest.
UK population of Turtle dove declined by 97% since 1970The turtle dove is Britain’s fastest declining breeding bird, and we have lost 97% of the UK population since 1970.
One of the major drivers of the turtle dove population decline in the UK is a reduction in the number of breeding attempts per pair, but next to nothing is known about what happens to chicks once they leave the nest.
Fitting turtle dove nestlings with radio tagsThe team attached small radiotags to the legs of 15 turtle dove chicks in eight nests, weighed them, and followed them for the next 35 days to find out how many survived and where they went after they had left the nest.
Turtle dove nestling named Adder.
Adder, one of the chicks tagged during this study. Adder fledged successfully and was last seen foraging in a farmyard 1 km from his nest, and near the new nest of his radiotagged parent. Photo Alex Ball
Eleven chicks successfully fledged from their nests. The remaining four were found dead very close to their nests, suggesting that these chicks had been predated around the time they were attempting to fledge.
Four more birds were found dead over the next 10 days: all four are likely to have been killed by mammalian predators as their remains were found underneath dense vegetation and feathers appeared chewed.
Chicks require seed rich habitatsDuring the first three weeks, the chicks made frequent short forays of, on average, 127m from the nest area, selecting habitats naturally rich in small seeds that, historically, formed a major component of turtle dove diet.
In our study area, seed-rich habitats included semi-natural grassland, quarries, fallow areas and areas of low-intensity grazing – mostly horses, with the occasional alpaca – that allow wild flowers and grasses to flower and seed. However, the birds still returned to the area near their nests, spending around 50% of their time within 20m of their nest.
Pegasus and Unicorn, two of the nestlings tracked during this study, photographed two weeks after they were tagged, still in the vicinity of their nest. Photo Jenny Dunn
Chicks disperse and begin migrationsAfter the first three weeks, the chicks dispersed from their nest area and were often found in flocks with other doves and pigeons. At this point, some even started to migrate: one chick was relocated 6 km from its nest site 30 days after tagging.
Heavier chicks had better chance of survival The researchers also looked at whether the weight of chicks at seven days old had any relationship to whether they survived, as well as whether habitat had any effect on their weight. Heavier chicks had a better chance of survival, and those with more seed-rich habitat near their nest were heavier at 7 days old, suggesting their parents were better able to find them sufficient food.
Chicks that were heavier when weighed at 7 days old had a better chance of survival. Photo Jenny Dunn
Practical application of the study results into the Countryside Stewardship SchemeThe results of this work have led to management recommendations for turtle doves in the new Countryside Stewardship Scheme, outlining the importance of maintaining or creating areas of seed-rich plants close to tall, dense vegetation that provides shelter and nesting habitat This combination is key in increasing the survival prospects of less mobile youngsters.
Planting areas of seed-rich plants close to good nesting habitat such as this can increase the survival prospects of young turtle doves. Photo Tony Morris
Find out more about our work on turtles doves through Operation Turtle Dove.
Guest blog by Dr. Mark Hancock Senior Conservation Scientist at the RSPB Centre for Conservation Science
Scottish lochs and their scoters
Complementing the majestic hills of the Scottish Highlands are its myriad lochs (lakes), ranging from huge lochs several miles long, running along broad glaciated valleys, to masses of tiny pools and lochans (mini-lakes), covering the surface of rolling peat bogs. Each summer a few of these lochs are favoured by nesting common scoters - large but shy diving ducks famous for their beautiful courtship displays.
A pair of scoters in relaxed mood at RSPB Forsinard Flows reserve in the northern Highlands and (inset) one of the iconic ducklings (photos: Andy Hay, RSPB)
Over the last few years I've been fortunate to have been given the chance to get to know this bird and its remote and magnificent breeding grounds, along with colleagues from RSPB, the Wildfowl & Wetlands Trust, Scottish Natural Heritage and The Conservation Volunteers. We're keen to work out how we can help this species, once so characteristic of the area, but recently much declined.
Why do scoters nest where they do? If we could answer this question, maybe we could use the information to help them recolonise their former haunts. So we designed a research study which compared lochs that scoters use, to other lochs that scoters have been abandoned: what's the difference?
What do scoters look for in a loch?
Over three years, we made nearly 1000 visits to lochs across the Highlands, looking for scoters, and measuring the things they might be looking for when they choose their breeding sites. Maybe scoters prefer the lochs with the most food - aquatic insects like caddisflies and mayflies, and other invertebrates, like freshwater shrimps. Perhaps they need lochs where insect life is easiest to catch - with shallower water or softer sediments. Or might the preferred lochs be the ones with the fewest predators? For example, American mink, not native to Scotland, are starting to colonise the Highlands, and they often prey on waterbirds.
One of the field teams at a loch in the Flow Country during the three year scoter study. (L-R: David Bavin, Helen Jones, Mark Hancock; photo: Martin Clift).
Sampling insects for food availability
Over the course of the study, nearly 50,000 individual freshwater insects and other invertebrates were sampled, counted, identified and measured. This allowed us to work out how much food was available for scoters at different lochs. We also measured loch depths and sediment types, and scoter use. Some lochs had scoters on nearly every visit, whereas others, formerly used by scoters, had no records during the entire study. Then we went back to base and analysed all the data: which of these characteristics tells you that a loch will be scoter-friendly?
Sampling loch insect life with a sediment grab (photo: Andy Hay, RSPB)
Large invertebrates & shallow water - a scoter's favourite loch
After years of fieldwork and months of data analysis, the study has been completed, and the results published here in the journal Aquatic Conservation: Marine and Freshwater Ecosystems. So, what have we learnt? Of all the different factors investigated, two come out clearly as being linked to scoter presence: large invertebrates, and shallow water. Of all the lochs we looked at, scoters bred most often at those lochs with the shallowest water and the most large, freshwater invertebrates. What's more, there was more freshwater insect life where there were fewer small brown trout - perhaps at some lochs, the fish were eating most of the scoter food?
Using research to help scoter conservation
We're now using these results to help design ways of helping scoters. For example, at hydro lochs, where water levels are to some extent under human control, could we aim to maximise the area of shallow water? In the north Highlands, where brown trout angling has declined in some areas, could we encourage more trout angling at certain lochs, and by reducing trout numbers, increase freshwater insect life? In the next phase of the work we will be working closely with those who use and manage these lochs, to see if we can together develop conservation measures. Let's hope we can keep the Scottish breeding population of this lovely bird, at our Highland lochs and lochans.