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Effects of winter-long provision of seed rich habitats on seed eating farmland birds - BD5210

Lack of seed during winter is known to be a major cause of farmland bird declines in Britain. Conservation measures that aim to provide winter seed include weedy cereal stubbles and wild bird seed mixtures (WBSM). Cereals are often lacking in livestock farming areas, and seed resources on WBSMs are usually exhausted by January. Lack of seed during late winter may limit bird survival and therefore prevent population recovery even where WBSM is provided. This shortage of seed during late winter has been termed the ‘hungry gap’ and may be a generic problem limiting the recovery of farmland bird populations.
Recent work has highlighted the potential role of ryegrass as a source of winter seed for birds. Patches of seeded ryegrass provided abundant seed throughout the winter and were heavily utilised by foraging birds into March, and even after vegetation clearance in April, although impacts on bird populations were not assessed.
This project aims to assess the benefits to farmland birds of providing seeded ryegrass in a pastoral landscape (North Wales) where other sources of winter seed are lacking. The impacts of two seed provision treatments will be compared at the landscape scale: WBSM only and a mixture of WBSM and seeded ryegrass. The former is expected to provide seed until mid-winter while the later should provide seed throughout the entire winter. We aim to provide seed-rich habitat at the target scale of 2% (as recommended in the Farmland Birds Package for arable landscapes) of the suitable habitat within designated intervention tetrads. The project will assess the impacts of seed provision on the winter foraging and body condition of priority farmland bird species, as well as impacts on overwinter survival and population size.
The primary aim of the study is to test whether the provision of seeded ryegrass can fill the late-winter hungry gap. As costs of seed-rich habitat provision at the landscape level are relatively high, replication is modest but adequate to demonstrate key bird responses and proof of concept. If the study confirms that seeded ryegrass can fill the late winter hungry gap, then additional replication may be needed to demonstrate statistically robust population-level impacts on target bird species.
The general aim of the study is to assess whether the provision of seeded ryegrass can fill the late winter ‘hungry gap’ for farmland birds in pastoral landscapes. Specific objectives are as follows:

1. To assess the practicality of providing wild bird seed mixtures and seeded ryegrass in a pastoral landscape at a scale that has the potential to generate population growth
2. To assess the impact of wild bird seed mixtures and seeded ryegrass on the foraging, diet, body condition and survival of seed-eating farmland birds
3. To assess the impact of winter seed provision on the breeding productivity of yellowhammers in Welsh pastoral landscapes
4. To test whether population growth of seed-eating farmland birds is dependent on the provision of seed-rich habitats during early or late winter
5. To measure any agronomic impacts of allowing ryegrass to set seed on silage production in the following year
Project Documents
• EVID4 - Final project report : BD5210 Effects on winter-long provision os seed rich habitats on seed eating farmland birds Final Report   (991k)
• ANX - Annex : BD5210 Final Report Appendices   (487k)
Time-Scale and Cost
From: 2012

To: 2015

Cost: £253,735
Contractor / Funded Organisations
Royal Society for the Protection of Birds
Environmental Stewardship