Striking findings for Heads Up for Harriers project this year

Cameras have shown four more birds to have fledged in 2016 compared to 2015, despite fewer nesting attempts.

Building on the success of 2015, the Partnership for Action Against Wildlife Crime Scotland (PAW Scotland) project was expanded from five to thirteen participating estates across Scotland.

The thirteen estates participating in the project agreed to have cameras installed on their land to monitor hen harrier nests. The cameras record images both on the nest and within the immediate area, to help better understand the reasons for nesting failure and improve hen harrier breeding success in the future.

Despite the greater coverage this year though, the numbers of nesting attempts, and therefore the number of monitored nests was down, from last year. There were five successful nests across three estates, fledging a total of fourteen birds.

Last year, three successful nests fledged 10 birds, with three nests failing (one due to bad weather and one due to fox predation).

Scott Smith, Heads Up for Harrier Project Officer for the South of Scotland, said “Hen harriers rely predominately on voles as a food source during pre-laying and throughout the breeding season. Vole populations are cyclical, with approximately five-year cycles. Low vole numbers have an adverse effect on hen harrier breeding numbers and productivity brood counts are also lower during these low cycles. It appears there was a crash of vole populations in the South of Scotland this year, which had a noticeable impact on the number of breeding attempts we have observed.”

As in previous years, the nest cameras have proved invaluable in determining reasons for failure, including a dramatic example of fox predation on one of the nests in Southern Scotland. Footage shows five healthy chicks (which appeared ready to fledge) being attacked by a fox, which visited the nest over the course of three days. The feisty chicks were able to fend off the fox, but unfortunately one was fatally injured and found dead near the nest.

Professor Des Thompson (Scottish Natural Heritage), Chair of the PAW Scotland Heads Up for Harriers Group, said “The Heads Up for Harriers project is vital in demonstrating the many natural challenges facing nesting hen harriers, as shown in the striking images captured by its cameras. As well as the fox incident, another nest in Banffshire suffered the loss of four chicks exposed to poor weather. If it wasn’t for the cameras, these losses would be unexplained. We even recorded the dead chicks being fed to a surviving chick by the mother, which is not uncommon among many raptors.”

“The absence of nesting hen harriers over much moorland in the east and south of Scotland remains a concern, and we need to do more to get to the root of this: food availability, predation, weather, disturbance and illegal killing are all part of the story”

Thanks to some excellent co-operation by the estate, the remaining Banffshire chick was satellite tagged as part of a joint RSPB Hen Harrier Life+ and Heads Up for Harriers project. The bird – named “Elwood” – left its nest on the 20^th July, but unfortunately the signal from the satellite tag stopped transmitting on 27^th July in the Monadhliath mountains, with Elwood presumed dead.

Professor Des Thompson continued “The loss of Elwood is very worrying, particularly given the reported loss of eight satellite-tagged golden eagles in the same vicinity over the last five years. We are reviewing these incidents and will report our findings in due course”.

Douglas McAdam, Chief Executive of Scottish Land & Estates, commented:

“We are pleased to have been fully involved again in this important project with more than double the number of member estates participating and a range of moorland management regimes included. Clearly, with the low vole cycle and weather factors, it has been a disappointing year generally for harrier breeding, but yet again the data gathered has built a much greater understanding of the causes of nest failure and the value of using the nest cameras has been reinforced. Our members have appreciated the collaboration with SNH staff and we hope that even more will volunteer next year.”

ENDS

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