Conservation project records new hen harrier behaviour

The discoveries were made as part of Heads Up for Harriers, a Partnership for Action Against Wildlife Crime Scotland (PAW) Scotland project, led by Scottish Natural Heritage (SNH). Figures released today also show 30 young birds have successfully fledged on participating estates.

On two occasions, a male harrier was recorded spending up to 35 minutes standing over or beside a nest, guarding the chicks when the female harrier was away from the nest. This is believed to be highly unusual harrier behaviour: usually, the only time a mother leaves a nest for the first six weeks is to briefly catch a food drop from the father. The male calls the female off the nest and drops food, which the female then catches to feed their chicks.

As well, after a hectic night of activity involving a fox and a short-eared owl, five chicks were eventually killed by a long-eared owl. The attack happened early in the morning this spring in the Langholm area of South Scotland.

Professor Des Thompson, Chair of the PAW Scotland Heads up for Harriers group and SNH’s Principal Scientific Adviser, said, “This is exceptional. It’s the first time we’ve observed such behavior by a male hen harrier, and the first time we’ve seen a hen harrier nest under attack by two other raptors, one after the other.”

“As ground-nesting birds, hen harriers already face extra obstacles in order to protect their chicks. That’s why it’s so important that we crack down on persecution against these vulnerable birds, which already face so many challenges to survive.”

Heads up Harrier project field worker, Scott Smith said, "These pictures tell an amazing story that helps us understand the kind of hurdles which hen harrier chicks encounter to survive. Nests can fail for many reasons: the Heads up for Harrier project is keen to learn everything we can to help hen harriers flourish in the future. The more information gathered about why some hen harrier chicks don't survive, the more we can find ways to safeguard them.”

According to the pictures from the nest camera, before the owl attack, the mother spent eight days taking care of her five newly-hatched chicks, until she was scared off the nest by a fox. The fox probably played a crucial part in the night’s events, as harriers aren’t likely to be flushed off nests by owls. The unattended chicks are surveyed first by a short-eared owl, and then killed by a long-eared owl. The long-eared owl ate three of the chicks. The mother then returned to recover and remove the remaining dead chicks just before dawn.

The other field worker for the project, Brian Etheridge, added, “We’re also seeing new behavior as part of the project. We’re surprised in this case that the long-eared owl didn’t take its prey away, but instead stayed at the nest for almost an hour. We haven’t seen an owl behave in this way before and can’t explain it at this point. We also don’t know why the fox and the short-eared owl didn’t eat the chicks when they had the chance.”

The Heads Up for Harriers project aims to help conserve hen harriers with nest cameras by monitoring nesting hen harriers and helping determine reasons that affect chick survival.

New figures for this year show a total of 27 Scottish upland estates took part in 2018, with 17 nests monitored. This year, 30 young birds successfully fledged from eight successful nests. Four nests failed at egg stage and another five nests failed with chicks. The primary reason for failure (at chick stage) was fox predation, accounting for the death of six chicks; however, owl predation and starvation due to adult birds not being able to provide enough food also played a part.

ENDS

MEDIA QUERIES - For more information, contact SNH media relations & PR officer, Vicki Mowat, on 0131 316 2659 or vicki.mowat@nature.scot or the main SNH press office on 0131 316 2655.

PICTURES – Please credit the Heads Up for Harriers project.