By Holly Appleby, Species Recovery Project Assistant, Uplands Research
In northern England, black grouse breed on the moor fringe, where females, also known as greyhens, often nest in rushy pastures and rear their chicks in rough grazings and grassy habitats. Unlike red grouse, hens rear chicks without help from males. The critical period for chick survival is the first three weeks after hatching in June when chicks are foraging on insects, particularly sawfly larvae. Greyhens are sensitive to disturbance, often leaving their broods unattended, making studying them during this critical period challenging.
One potential solution to study their movement and behavior without disturbing them is by monitoring of birds remotely through the use of GPS tags. These solar-powered tags record and transmit a bird’s location in real-time at programmed intervals throughout the day and night. Deployment on black grouse would allow their movements to be studied without disturbance, but is a novel approach.
Under special licence from the British Trust for Ornithology (BTO), we were granted permission to trial this technique on black grouse as part of our Black Grouse Range Expansion Project, funded by Natural England’s Species Recovery Programme. We deployed GPS tags on a total of seven females in spring 2024. To fit a black grouse with a GPS, it must first be caught. This has involved roaming the moorland edge over long, cold, dark nights – not always a pleasant experience but definitely a rewarding one. By the end of the summer, one bird had lost her tag, and one was found dead on the road, but the five remaining tags were still active.
The tags allowed us to track bird movements and through this identify nest sites, start of incubation, hatch date, brood foraging and roosting locations, and calculate brood home ranges. Last year, we found that all five females nested, but only three hatched chicks. All broods were lost, two within the first week, and the third at 27 days. We think that chick losses were linked to low numbers of insects during the chicks’ first two to three weeks. Over this winter, a further 17 greyhens have been tagged and birds will be monitored through the 2025 breeding season to investigate how brood habitat use and brood survival relate to insect abundance, sward height, structure and composition. This information can then be used to help inform grazing regimes to create the desired brood-rearing habitats in rough grasslands on the moorland fringe.
Over the past 12 months, we have successfully fitted GPS tags to 24 greyhens. Deployment of these tags and subsequent monitoring would not have been possible without funding from Natural England’s Species Recovery Programme, Farming in Protected Landscapes, BASC Wildlife Fund, or without the help from the local gamekeepers who have been fantastic at helping us to locate female black grouse for this study.