Migrating south

Two harsh winters in a poorly heated woodland house would be enough to test most people’s resolve. Ice on the inside of the bedroom and puffed up like ‘Michelin’ marshmallows we held on each day for the allocated evening heating. My wife’s semi-Italian blood just found it too extreme, despite last Christmas’s present of an electric blanket. So with some regret about leaving the Pinfold’s peacefulness and woodland wildlife, I moved with my family over the summer from Nottinghamshire to Devon warmth. Of course it was not just the more amiable climate that pulled us South, but my desire to be part of a richer more stimulating landscape with greater biodiversity. Devon had always appealed to me with its mix of extensive coastline, moors and rivers.

We have moved to a cottage on the outskirts of Totnes within the wooded Gatcombe valley, with its rolling hills, high hedgebanks and gentle streams, views to Dartmoor and easy access to South Hams coastline. The wildlife experienced already has certainly not disappointed. An evening woodland walk was rewarded with a badger sighting. From our own home I was surprised by a darting Kingfisher slightly off track from its aquatic path. Three times I have seen a Sparrowhawk swooping through the cluster of cottages trying to take Sparrows by surprise. I even got a glimpse of a Peregrine soaring overhead as I painted a skylight, whilst the ever present buzzards glide by effortlessly, heralded by their mewing cries. Botanically the valley is rich in hedgebank & woodland plants and particularly noted for species of Crane’s-bill (see image of Long-stalked Crane’s-bill). Further afield I have treated myself to Cirl Buntings on the nearby coast and rock pool diving to see Blue-rayed Limpets and star ascidians amongst many marine species.

In recent weeks I have become aware of Nature’s more natural migration with swallows collecting on telegraph wires and family groups of House Martins’ collectively feeding on the roof of Butterwell Cottage. They too have to make decisions about climate and make the difficult journey south, whilst we hopefully will be enjoying our first comparatively warmer winter in our new cosy cottage.

Blackcap warming to English winters

During a recent visit to my parents in Ledbury, Herefordshire, I was delighted to see the distinctive Blackcap (Sylvia atricapilla) frequently feeding from their birdtable. This warbler is probably the easiest to identify with distinctive skull caps, black in males and a chestnut brown in females. Like many other warblers, the Blackcap is a summer migrant to Britain. However since the 1960’s it has been increasingly seen staying over during the winter, particularly in southern England - I have never seen this species where I live in Nottinghamshire. Why have a growing proportion of Blackcaps decided not to migrate during the harsher winter conditions?

Migration clearly requires a high cost to the ‘traveller’, in terms of energy and ‘in-flight’ hazards. If the benefits of staying put over winter outweigh those of migration, you might predict that some would be tempted to stay. It would appear that the Blackcap with more eclectic tastes than other warblers more reliant on insects, has taken advantage of the growing bounty found on English birdtables. It has also been proposed that it is also a good example of how some wildlife is responding to climate change and warmer British winters, which might well lead eventually to complete residency as temperatures continue to rise (Pulido & Berthold). So, although many households welcome this addition to their gardens in winter, its increasing presence may also be a warning signal of continued climate change and less welcome impacts on other wildlife.

I guess it won’t be long before the Blackcap will start to turn up more frequently at birdtables in the Midlands and further North.

Pulido, F. and Berthold, P. (2010) Current selection for lower migratory activity will drive the evolution of residency in a migratory bird population. PNAS, 107 (16): 7341-7346