They [the Pine Siskins] were exceedingly fond of sunflower seeds, but their bills were so tender that they were hardly able to crack the hard shells so as to obtain the kernel inside. So they would watch their opportunity, and whenever an Evening Grosbeak came to the feeding-shelf and began cracking the seeds, he would be surrounded by several of the Siskins. As he cracked the seeds, some particles of the kernel would scatter from his beak, and immediately the Siskins would rush in and gobble them up.