The old quarter of the capital, the Walled City, possesses a distinctive Muslim culture - because it used to be the capital of the Mughal emperors who ruled India for centuries. Since the court was here, so was the Muslim aristocracy, with its own social traditions. These included falconry, flying pigeons and keeping exotic birds in cages as a status symbol - a custom that originated in the mixed Arab and Central Asian ancestry of the Mughals. This tradition has survived through the ages, as families in the Walled City continued to keep parrots and lovebirds in gilded cages. Pigeon lovers abound in this fantastically congested district. Chandni Chowk used to be Old Delhi's main thoroughfare. A walk through it now - past the teeming cycle-rickshaws, oxcarts, tiny shops selling sweets and fried snacks, and honking cars and scooters - takes you to the house of a bookbinder, Naseem Khan. Climb the winding staircase up three floors to his rooftop, and the view is spectacular - a vast expanse of flat rooftops, relieved only by the great domes of the red sandstone mosque built by emperor Shah Jahan. Up here, under a vast sky, with the call to prayer from the mosque reverberating all around, you get a sense of the grandeur and elegance of the Muslim aristocracy that dominated the quarter. From these rooftops, hundreds of aristocrats and wealthy merchants used to fly pigeons. Mr Khan has hundreds of pigeons. His family have been handling them for generations. 'These birds, they have feelings,' he said. 'This was once the sport of kings and nawabs [Muslim royals]. It was the pastime of gentlemen once but is dying out now.' There is even a bird hospital here which cares for hundreds of sick or injured birds. Some have splints on their legs, others bandages on their wings. The hospital is run by a religious charity. Keeping parrots is permitted by Indian law. But the Walled City is now the centre of an illegal trade in rare birds - falcons, owls, eagles, hill mynahs - all of which are guarded by the Wildlife Protection Act for fear that they might become extinct. It is also illegal to keep or train falcons and hawks. But trappers catch these birds in the forests and smuggle them into the Walled City, where they sell them for high prices. A police raid last month recovered over 700 rare birds. Some are sold as exotic pets. Others are sold for use in black magic or traditional medicine. 'On any given day, I'd guess that around 50,000 birds are brought here. They're sold openly,' says Mr Khan, stroking a cupped pigeon. 'It saddens me that we were once known for our love of birds, and now we're known for an illegal trade in these beautiful creatures.'