The bird's movement is compared to that of a lizard. The basis for this comparison is that both the bird and the lizard exhibit sleek, abrupt, and alert movements. This similarity in movement style provides the foundation for the comparison, highlighting the bird's agile and sudden motions akin to those of a lizard when it arrives on a tree branch. This comparison is often used to describe the goldfinch's movement on the laburnum tree in poetry and literature contexts.
