Monday 23 April 2012

Ravens



The other day, a trip to Bristol to meet up with the BBC SpringWatch Team delivered an unexpected surprise in the form of a pair of urban Ravens. We had hoped that we might see an urban Peregrine, as the city now supports several pairs, but proved to be disappointed by the lack of birds at a regular haunt. Of course, the Ravens more than made up for this as they are a still a rare visitor to Norfolk and to see them in an urban setting was totally unexpected.

The return of the Raven to our urban centres comes after a gap of many centuries and reflects a broader recovery of its breeding population. Up until the end of the nineteenth century you would have been able to find Ravens breeding in just about every English county, but the ongoing persecution soon saw the species lost from most of its former breeding range. Ravens are scavengers for the most part, taking carrion or foraging among the refuse of our society. They also take a surprisingly large amount of plant material, including cereal grains, berries and even grasses, together with invertebrates, small mammals and small birds. It is the preference for carrion, especially that associated with livestock, that has contributed to their persecution over the years but a more enlightened attitude has aided their recovery.

It is the western strongholds that have driven the recovery, the population expanding slowly but steadily eastwards into southern and central England. Established pairs tend to remain within their breeding territories throughout the year but young birds undertake larger movements and it is these individuals that have colonised new areas. Some of these dispersive movements can be substantial as highlighted by the recovery of a juvenile Raven at West Stow (just over the border into Suffolk) back in 1988; this individual had been ringed as a chick the previous summer in Ireland. Breeding pairs are now established in Sussex and Kent and to the north of London, but the species is still some way off re-establishing itself in East Anglia.

Bristol it seems, now has an interesting mix of larger birds. In addition to the Peregrines and Ravens, there is a sizeable population of inland-breeding gulls, dominated by Herring Gull and Lesser Black-backed Gull. For me it is the Ravens that steal the show. The sheer size of these birds – we were lucky enough to see them alongside a Carrion Crow, which they dwarfed – and the wonderful croaking call, deliver a powerful sense of character. With luck, we will see them return to Norwich one day, our attention caught by a croaking call and an upward glance will reveal the silhouette of this striking bird.


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