The common nightingale, Luscinia megarhynchos, is a songbird associated with dense low vegetation in its breeding habitat. Its familiar song and its habitat requirements provide different ways to study the same organism: vocal behaviour concerns communication, while settlement and movement reveal responses to vegetation structure.
A woodland experiment created eight paired areas in which deer were either excluded or allowed to browse. Territory mapping and radio tracking showed strong nightingale use of the protected regrowth. [ref]
Experimental evidence that deer browsing reduces habitat suitability for breeding Common Nightingales Luscinia megarhynchos by Chas A. Holt and others. 2010, abstract: eight paired exclosures and controls, territory mapping and radiotelemetry
Tracked birds spent 69% of their time in the protected 6% of the study area. This links browsing to habitat use through an intervention, rather than inferring the mechanism solely from parallel population trends. New to topics? Read the docs here!