Rooks: the Roost and the Rookery

In early December I wrote: “It is five to four and dusky already. There is a thickening mist and the local Forncett St Mary rooks are gathering to fly to their roost.”  “I can hear them up high in the willow, their conversation is much louder than earlier in the afternoon. Then, it was a quiet murmur but full of greeting and exchange. They have reached an excited crescendo both mellow and full of loud cawing and suddenly they fly off in a North/ North Westerly direction into the descending night.”

 I have at last discovered from Mark Cocker, celebrated Norfolk naturalist, that at this time of year, Forncett’s rooks fly all the way to Buckenham Carrs, in the Yare Valley, to roost within the Great Wood that offers protection from weather and predators.  The expression ‘as the crow flies’ is embedded in our national psyche and this splendid, linear measurement of distance, across a landscape, describes the purposeful, clearly visible, flight lines of rooks making their way towards their evening destination. Farm workers used to down tools when they saw the homeward procession of the rooks. In Macbeth Duncan says, ‘Light thickens and the crow makes wing to th’ rooky wood.’  The birds in the roost are a community, known as a ‘parish of rooks.’ The Forncett rooks are drawn to the site by what Cocker calls ‘an inherited pattern of attachment’. Generations of their community have travelled to Buckenham Carrs over hundreds of years to join the thousands of others, jackdaws included. He describes the ‘whiffling’ birds approaching Buckenham Carrs as dark closes in “…in a joyous hubbub … sometimes descending in a wild, downward, tumbling flight with switchback twists and swerves.” Perhaps this behaviour, that is beautiful to watch, confuses and challenges potential predators. It may be ‘old behaviour’ from perhaps five hundred years ago when Norfolk was full of eagles!  In the morning the Forncett rooks leave at dawn and travel 20 miles or so back to their feeding grounds in our villages.

 Rooks have bare, pale grey beak patches, slender, burnished beaks and full leg feathers: crows do not have these shaggy trousers. They belong to the crow family, the CORVIDS, and are highly intelligent. It includes: the magpie, jay, jackdaw, crow and hooded crow, raven and chough.  They feed on vegetable material – acorns, berries and seeds - and on worms and grubs in the soil including wire-worms, foraging on pasture and arable land with their strong bills.

The roosts are at their peak in January and by mid March they have vanished as the rooks transfer their allegiance to the rookery. My neighbours in Forncett St Mary who have a rookery in the copse that adjoins their garden tell me that the rooks build high in the birch, beech and ash trees. When they had horses the rooks would collect strands of horsehair to weave into their nests. They have grown used to the varied sounds of the rooks and enjoy them. The rooks plunge downwards onto their lawn in the spring and bring their fledgelings to feed beside them.

 In Forncett the rookeries are small. These birds, that like to build in tall clusters of trees, seem to have had to disperse themselves into several places because in recent decades large trees have been felled by people or storms. The 1987 hurricane, for instance, ravaged the lime avenue leading up to the rectory and St Peter’s church.  The rookery is of central importance from March to June when the rooks re-pair and build the nests, hatch their eggs and feed and fledge their young. Curiously they raid each other’s nests for sticks, moss and grasses. In spite of this their social organisation is complex and highly developed. Its basis is the monogamous pair, but the rook flock is close and communicative.

Their courtship ritual is elaborate: the male rook bows several times to the female with drooping wings, cawing and fanning his tail and the female displays in return. Throughout the year the paired rooks ceremoniously twine their bills. Some young will leave their parents when fledged, others will remain for a year or so, helping to rear the next generation.

They are able to live together in large groups without conflict through their skills of mutual recognition and their ability to learn quickly. They recognise family members and accept and re-introduce rooks that have left and then returned to the rookery. They also recognise their human neighbours and assess whether they are benign or threatening. They have large brains and their minds are formed for exploration and discovery. “They use their wisdom to infer, discriminate, test, learn and remember, to foresee, mourn and ward off danger…” (Woolfson). They are capable of informing each other of what they observe and understand.

As a young man, naturalist Jim Perrin, watched a gamekeeper shoot a magpie and walk away, leaving it on the ground to string on his gibbet later. Five others flew towards the dead bird, hopping round it and crooning softly, laying strands of grass across its handsome pied body. This lasted perhaps five minutes before they flew away.  Before the old Norwich library burnt down in 1994 I borrowed and returned a book written by a Norfolk clergyman in the early 20^th century. He recorded a very similar ritual of grief as rooks mourned for a fledged youngster, who in high wind had dived too fast or inexpertly and lay dead beneath the rookery.

Corvids have been seen in past centuries as representatives of darkness and threat because of their black feathers. This is a prejudice they do not deserve. Their dark feathers are protective and offer both camouflage and metabolic advantageas they readily absorb solar energy. Like other birds they sunbathe, spreading their wings to warmth and light, regulating their temperature and accumulating vitamin D. The feathers are a rich black, glowing with a purple and navy lustre.

They are passerines, perching birds. Their feet close as their ankles bend, the tension of the tendons curling the toes that tightens their grip on the swaying upper branches of tall trees.

Corvids, like apes and humans, have evolved within social groups and this complexity and demand for mutual recognition, neuroscientists suggest, explains their intellectual ability and high brain to body ratio.

February 2021

Sources

Corvus, A life with Birds by Esther Woolfson, 2008

Crow Country by Mark Cocker, 2007