Faced with a soaring population of noisy parakeets affecting the environment, city authorities in Madrid said Monday they have decided to take steps to cut their numbers.

The Spanish capital is home to some 12,000 Argentine quaker parrots which are common in much of South America and compete with other birds for food and rip branches from trees to build their nests.

The breed was originally pet but have since proliferated to a degree where Madrid authorities say their numbers need bringing down.

In a statement, city hall said it has drawn up a plan "to reduce and control the population" without giving a figure. 

One element of the plan would involve sterilizing eggs in the nest to encourage females to incubate but not hatch them.

The distinctive green-plumed, grey-breasted creatures - also known as monk parakeets - "have become a concern for a number of citizens," said Borja Carabante, municipal officer for environmental affairs in the capital.