Studies of priority woodland birds

We are investigating causes of population decline for our most rapidly declining woodland birds with the aim of reversing these trends.

Hawfinch

Overview

Woodland habitats in the UK have 11 bird species of high conservation concern due to large population declines. For the most rapidly declining species we are undertaking research to identify the causes for these declines and identify conservation interventions which could help slow or reverse declines.

The species involved are from a wide range of woodland habitats, have different distributions across the UK and have different ecological traits. It is therefore highly unlikely there is a single pressure on woodland habitats leading to the declines of this diverse group of species. We are approaching the problem by concentrating on individual species.

We are currently trying to identify the causes of decline for two of our long-distance migrants, wood warbler and pied flycatcher and the resident hawfinch. We are also investigating whether habitat management at the site and landscape scale can be used as an effective conservation tool to manage willow tit populations.

Objectives

  • To identify demographic stage most likely to be causing population declines in pied flycatcher.
  • To identify year to year return rates of breeding wood warblers and locate wintering areas in Africa.
  • To find out if a decrease in breeding success is a likely cause of hawfinch population declines.
  • To test whether habitat management aimed at improving woodland structure for willow tits has a positive effect on habitat use and site populations.

Progress

Data on breeding success, adult return rates and juvenile recruitment have been collated from well monitored long running pied flycatcher nest box studies.

Return rates of individual wood warblers have been monitored annually since 2012 from a Devon population. Based on this information, light detecting geolocator tags were fitted to a sample of birds in 2016. It is hoped these will identify the area of Africa in which these birds spend the winter.

From 2013 to 2016 we were able to locate and monitor breeding success from more than 50 nests in Wales and the Forest of Dean by following females fitted with miniature radio transmitters. The nests were monitored using a combination of cameras and observations from the ground and the outcomes will be used to assess rates of breeding success compared to historical data. 

Sites were selected in 2014 for trial habitat management designed to improve habitat structure for willow tits along with similar sites without management. Baseline information on willow tit populations, habitat structure and availability of habitat surrounding the sites were collected between 2014 and 2016. Habitat management has been carried out by 2017 and the location and extent of management recorded. 

Planned Work

Data on breeding success, adult return rates and juvenile will be analysed to see which aspects of the pied flycatcher lifecycle are most strongly linked to population declines.

In 2017 we will retrieve the geolocators from birds returning to their Devon breeding grounds. We will analyse the data received from these before deciding on future direction of study for this population.

We are currently analysing hawfinch breeding success from more than 50 nests monitored by the project and comparing with trends recorded by national monitoring since the 1940s. From 2017 we will be trialling the use of miniature GPS trackers to monitor foraging patterns and detailed habitat use.

The habitat management will take several years before it reaches a stage where the habitat will be suitable for willow tits. We plan to return in 2021 to record the response of habitats and birds to the management.

Results

For wood warbler we have identified that breeding success has not changed between recent years and the 1980s when populations were high and neither changes in the time of breeding nor food supply have affected breeding success. We have also shown changes in habitat quality have not been the cause of widespread population declines for wood warbler and pied flycatcher. For these two migrant species we have failed to find a significant effect from factors operating in the breeding season on population declines.

Across the UK, more hawfinch populations have been lost from areas which had less broadleaved woodland cover and from areas which had greater signs of recent woodland management. This supports historical information which showed hawfinches as frequently breeding in non-woodland habitats such as hedges, gardens and orchards compared with hawfinches currently breeding mainly in well-wooded landscapes.

The willow tit trial management project was set up between 2014 & 2017 recording initial willow tit locations sites and a 1km buffer around them, the initial structure of habitat, and the location and extent of habitat management carried out over three winters. We will return in five years to record the response of birds and vegetation. 

Funding

  • Projects are funded by RSPB and Natural England through Action for Birds in England and Devon Birds.

Contacts

Coast on a stormy day

Paul Bellamy

Senior Conservation Scientist, Conservation Science

paul.bellamy@rspb.org.uk
Coast on a stormy day

Dr Malcolm Burgess

Senior Conservation Scientist, Conservation Science

malcolm.burgess@rspb.org.uk
Coast on a stormy day

Dr John Mallord

Senior Conservation Scientist, Conservation Science

john.mallord@rspb.org.uk
Coast on a stormy day

Will Kirby

Conservation Scientist, Conservation Science

will.kirby@rspb.org.uk
Tagged with: Country: England Country: Scotland Country: Wales Habitat: Woodland Species: Hawfinch Species: Pied flycatcher Species: Willow tit Species: Wood warbler Project status: Ongoing Project classification: Ongoing Project types: Research