Final answer:
The narrator believes an unusual idea about blue jays, seeing them as attention-seeking and talented birds without formal training.
Step-by-step explanation:
The narrator in the passage believes an unusual idea about blue jays. In the first excerpt, the narrator describes the blue jay as a noisy coxcomb in a gay light blue coat, pretending to be on good terms with every songster of the grove. This portrays the blue jay as an attention-seeking, showy bird. In the second excerpt, the blue jay is mentioned as trilling pretty well, even though it never studied the gamut. These descriptions suggest that the narrator sees the blue jay as a confident and talented bird despite its lack of formal training or musical education.