In the 1970 ’ s, a research group led by Peter and Rosemary Grant began studying these finches and discovered that after a year of drought, finches that had slightly bigger beaks survived more readily than those with smaller beaks.
त्यांना असे आढळले की वर्षभराच्या दुष्काळानंतर ज्या फिंच पक्ष्यांच्या चोचींचा आकार किंचित मोठा होता ते टिकून राहिले आणि लहान चोचीचे फिंच पक्षी मरून गेले.