Pied flycatcher

Overall vulnerability

Feature assessed:

• Pied flycatcher (Ficedula hypoleuca)

Special qualities:

• Internationally important and locally distinctive wildlife and habitats

Feature description:

A small bird and a summer visitor to the PDNP, the pied flycatcher spends its winters in West Africa and returns to nest in the spring. It is easily recognisable by its distinctive black and white ‘pied’ plumage. It can be found in upland broadleaf woodland, where it nests in knotholes and nest boxes and performs its characteristic fly catching behaviour. Caterpillars, slugs, and other ground-based prey are also an important food source, especially during nesting season. The pied flycatcher is a red listed bird in the UK, and the PDNP population is important for its conservation.

How vulnerable are pied flycatchers?

Pied flycatchers in the PDNP have been rated ‘high’ on our vulnerability scale. This score is due to high sensitivity and exposure to climate change variables, but a moderate current condition, and a moderate adaptive capacity.

Pied flycatchers in the PDNP appear to be doing reasonably well, with known populations doing better than the national average. Trophic mismatches with their nesting food sources are likely to increase as climate change shifts the timing of annual events such as migration and leaf bud burst. Climate change effects in West African wintering grounds will also be important. The moderate adaptive capacity of PDNP populations mostly relies on good management of key sites.

Current condition:

Pied flycatchers are nationally declining, having decreased by 42% in the last 22 years and ceased breeding in many places. Known populations in the PDNP appear to be doing better than the national average. However, there has never been a full census so some ‘unknown’ populations may have already been lost. Nesting boxes are kept for pied flycatchers in Padley Gorge and Stanage woodlands, and other species are prevented from using them. Populations in such locations are currently stable. Climate change is already having an effect on pied flycatchers in the UK. This is mostly through trophic mismatch due to advanced leaf budding date. See section ‘Other indirect climate change impacts’ below for more detail.

A study in Stirling found grey squirrels to affect 4-7% of nests, which if replicated in the PDNP would imply a large loss of young birds to nest predation. However, many of the PDNP population nest in boxes that are strengthened, so this may lessen predator impact.

What are the potential impacts of climate change?

Overall potential impact rating

Direct impacts of climate change

Warmer conditions earlier in the year are likely to increase the phenological mismatch between pied flycatchers and their caterpillar prey. This has already occurred as warming has moved leaf budding dates earlier in the year, and only the more adaptable caterpillars have advanced their population boom to match. As caterpillars provide a large proportion of pied flycatcher food during nesting, this mismatch has left them with less food available during this crucial period. Some birds have moved their nesting dates forward to match, but pied flycatchers are less able to do so, possibly due to other factors influencing migration dates. Data Certainty: Very High

Summer storm events may reduce breeding success. Storms can put environmental stress on pied flycatchers and reduce the activity of their invertebrate prey, especially flying insects. Breeding success would be lowered as a result and adult condition reduced, causing increased fatalities on return migration later in the year. Data Certainty: Low

However, increased average annual temperatures may have a positive effect on pied flycatcher populations. Higher temperatures during nesting correlate with larger clutch sizes. This may be due to greater invertebrate activity and abundance, but the full causation is unclear. Both nestling and fledgling success are also increased by warmer conditions. Decreased precipitation during nesting is also correlated with increased nestling success. The causation is again unclear, but again may be related to increased invertebrate abundance and activity. The combined effect is that warmer drier springs are likely to lead to increased breeding success in pied flycatchers. Data Certainty: High The relationship of these effects and phenological mismatch is unclear.

Other indirect climate change impacts

Delayed onset of the rainy season in West Africa may also increase phenological mismatch. If rains arrive later in the year, the start date for migration to the UK may also be delayed. This effect could increase as the gap widens between the advanced leaf bud burst in the UK and delayed arrival. This will limit the ability of pied flycatchers to adapt to earlier bud burst, while UK resident bird species may adapt and therefore have a competitive advantage. Data Certainty: Moderate

Changes to the wintering grounds may have a significant effect. Predicted rainfall change across West Africa is variable, so some wintering sites may become more desirable, but others less so. Droughts may play a role in this, becoming more prevalent and severely reducing the suitability of habitat. Desertification is likely to be significant, with some habitat lost as the Sahara expands. Sea level rise will also affect wintering grounds. Coastal sites may be lost as sea levels rise, and many more affected by saltification, reducing their suitability. This will increase competition for resources at the remaining suitable sites, reducing the condition of birds before their migration. Combined with the challenge of crossing a larger and drier Sahara, this may lead to fewer birds returning to the PDNP in the spring. Data Certainty: Moderate

Invasive or other species interactions

Increased average annual temperatures could increase the prevalence of pied flycatcher parasites. This would reduce bird condition overall, and certain blood parasites have been shown to cause shorter wing and tail length in males. This would be a particular problem during migration, where these effects can increase migration fatalities and delay arrival in the UK. The timing mismatch between pied flycatchers and their spring nesting food sources could therefore increase. Data Certainty: Moderate

Human behaviour change

Hotter drier summers may lead to increased visitor numbers in the PDNP. The effects of increased disturbance will be greatest at popular sites such as Padley Gorge - an important nesting location. However, this impact should be small compared to other factors acting on pied flycatcher populations. Data Certainty: Low Climate change mitigation efforts may lead to an increase in habitat for pied flycatchers. Woodland establishment for carbon offsetting and natural flood management may increase available habitat for this and other woodland birds. However, as mature trees with knotholes are preferred this is unlikely to increase significantly habitat in the short term unless nest boxes are installed. Data Certainty: Low

What is the adaptive capacity of pied flycatchers?

Overall adaptive capacity rating

The PDNP populations of pied flycatchers are small and relatively isolated, and so are quite vulnerable to change. However, the pied flycatcher has a large summer range across Europe and Asia, and there is gene flow and migration between breeding sites - pied flycatchers hatched in the UK are known to have bred in the Netherlands. This means that birds from elsewhere could bolster the PDNP populations or in an extreme case recolonise the PDNP.

Climate change will affect European countries differentially, so climate change refugia may contain healthy pied flycatcher populations that can spread to the UK, for example montane populations in southern Europe are predicted to be better off than UK populations. Data Certainty: Moderate

Pied flycatchers are relatively resilient to habitat change. Although they require broadleaf woodland, they are known to inhabit a variety of tree assemblages, meaning that they may be able to cope with future woodland change. They also feed on a wide variety of invertebrate prey, so changes in the invertebrate community may be possible to overcome. Data Certainty: Moderate

Pied flycatchers are a favourite among birdwatchers, so organisations such as the RSPB, National Trust, and PDNPA are likely to continue working on their conservation. Unfortunately, there are few economic incentives for private landowners to work on their conservation, as even creation of woodland habitat is a less favoured environmental land management scheme option. Some areas of importance to pied flycatchers are covered by Site of Special Scientific Interest (SSSI) designation, including important sites such as Stanage woodlands and parts of Padley Gorge. However, UK based institutions, schemes, and designations will only be effective up to a point, as the West African breeding grounds are also vital to pied flycatcher populations. Data Certainty: Moderate

Management practices for pied flycatchers are relatively well known, having been a focus in some sites for a long time. Nest boxes are known to improve survival, being preferred by pied flycatchers to natural cavities. Studies at the Longshaw Estate have shown that new boxes are beneficial, with an increase in uptake after these were built. Nest boxes facing south-west are associated with reduced breeding success, so orienting boxes correctly is a common practice. ‘Corking’ of nest boxes is used to prevent native birds from moving in before pied flycatchers arrive, and so reduce nest competition. This could ameliorate some of the effects of trophic mismatch. Pied flycatchers are a very well-studied species both in the UK and Europe, and are relatively well understood, allowing management practices to be more effective. However, it is not fully understood the extent to which pied flycatcher populations are dependent on breeding success compared to wintering survival, but it is thought that wintering survival is a significant factor. Therefore, UK based management plans can only ever be partly effective. Data Certainty: Very High

Key adaptation recommendations for pied flycatchers:

Improve current condition to increase resilience

The current condition of a feature is an important factor alongside its sensitivity and exposure, in determining its vulnerability to climate change. These recommendations are aimed at improving the condition of the feature at present, therefore making it better able to withstand future changes to climate.

• Suitable broadleaf woodland and new broadleaf woodland in the Dark and South West Peak should be fitted with nest boxes as soon as possible, including increasing nest box numbers within existing sites. This is the best way to increase pied flycatcher habitat and would help to improve resilience.
• Implement known best management practices on nest boxes such as corking and orienting away from south-west. Ensure continuity of management. More sustainable long term strategies may need to be considered.
• Increased upland woodland establishment, especially oak woodland, will increase habitat for pied flycatchers.
• Manage for increased Lepidopteran (caterpillar) populations to increase nesting food supply for pied flycatchers.
• PDNP based management can only do so much for pied flycatchers and other migratory birds. Partnership with West African conservation groups and others along the migration route would be the best way to increase winter survival.
• Investigate natural dynamic land management for pied flycatcher and other species. Pilot a ‘rewilding’ or ‘wilding’ trial scheme with no fixed conservation aims and monitor the impact on this feature.
• Encourage further uptake of environmental land management schemes by farmers within the PDNP.