Corporate report

Hen harriers: tracking programme update

Data collected from 2002 to 2017 on hen harrier dispersal behaviour.

Documents

Latest hen harrier tracking data from 2002 to 2017

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Figure 1. Radio tracking data from 2002 to 2006

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Figure 2. Satellite tracking data from 2007 to 2016

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Figure 3. Combined radio and satellite tracking data from 2002 to 2016

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Details

The hen harrier is one of England’s rarest and most spectacular birds of prey.

Hen harriers currently breed on heather moorland in the uplands across the UK and in a range of upland and lowland habitats across Europe.

Natural England is working with a range of organisations to conserve the species and this work contributes to one of these actions. See the Defra hen harrier action plan for more information.

Tracking hen harriers

For 15 years Natural England has tracked hen harriers to research their dispersal behaviour using a combination of radio and satellite devices.

The satellite tracking devices are lightweight transmitters. These are harnessed to the back of fledgling harriers. The devices can work for at least 3 years and locate any tagged bird to an accuracy of within 150 metres. This accuracy is dependent on the tag being able to recharge using solar energy at least every 48 hours.

Between 2002 and 2017 Natural England tracked 158 individual hen harriers of which:

  • 6 were still alive in 2017
  • 16 died of natural causes
  • 3 were known to have been persecuted

The fate of the remaining 133 is unknown.

Read the latest hen harrier tracking data sheet (updated September 2017).

Radio tracking data from 2002 to 2006

Early radio tracking technology recorded 99 birds. Figure 1 shows the location of birds from this data. Observations were made from birds fitted with wing tags and radio tags. The limitation of this technology does not provide a complete picture of bird movement.

Satellite tracking data from 2007 to 2016

Figure 2 shows the movement of birds obtained from the satellite tracking data covering 59 birds.

Hen harrier dispersal from 2002 to 2016

Combined radio tracking and satellite tracking data shows the movement of hen harriers. Figure 3 shows movement of all the tracked birds across the UK and Europe.

More information

Read more about the initial findings from the hen harrier tracking programme 2007 to 2014.

Published 18 September 2017