They are most commonly found at altitudes between 400 metres ( 1,300 ft ) and 1,000 metres ( 3,300 ft ) , only rarely below ( in Northern Germany sporadically down to 25 metres ( 82 ft ) ) .
They are most commonly found at altitudes between 400 and 1000 m , only rarely below ( in Northern Germany sporadically down to 25 m ) .