The ability to unlearn a previously established association is an important component of behavioural flexibility and may vary according to species ecology. Previously, two closely related sympatric Darwin’s finches were found to differ in their learning abilities. Small tree finches (Camarhynchus parvulus) outperformed woodpecker finches (Cactospiza pallida) in reversal learning but performed worse in an operant task. We attributed this difference to the habit of woodpecker finches to engage in long bouts of energetic pecking during extractive foraging. Persistently repeating one action without reward could favour performance in operant tasks but also limit behavioural flexibility. Here, we tested whether perseverance is the reason for woodpecker finches’ depressed reversal learning performance. Two new reversal conditions allowed the disentanglement of two sources of error in reversal learning: perseverant choice of the previously rewarded stimulus and failure to respond to the previously non-rewarded stimulus. For the within-species comparison, we predicted that woodpecker finches should find it more difficult to learn to avoid the previously rewarded stimulus than learning to choose the previously non-rewarded stimulus. For the species comparison, we predicted the woodpecker finches should make more errors of perseverance than small tree finches. As performance could also be influenced by reaction to novelty, we compared neophobic responses between species and related them to reversal learning proficiency. We found no significant difference in reversal learning in the predicted direction, but found a negative correlation between neophobia and reversal learning at the inter- and the intraspecific level, which points towards a general relationship between reaction to novelty and flexibility.