Though Perry is anthropomorphic , he do not speak , only communicating through an " aggravated purr " type of noise made by flapping his bill . This noise is provided by actor Dee Bradley Baker ; to this day , Povenmire and Marsh do not understand how Baker produce the noise . Thomas Sangster , who play Ferb , is notoriously good at making the noise and is considered second only to Baker himself . When in his " Agent P " persona , Perry is almost completely silent .