Individual Variation in Dietary Wariness Is Predicted by Head Color in a Specialist Feeder, the Gouldian Finch

Abstract

Shifts in resource availability due to environmental change are increasingly confronting animals with unfamiliar food types. Species that can rapidly accept new food types may be better adapted to ecological change. Intuitively, dietary generalists are expected to accept new food types when resources change, while dietary specialists would be more averse to adopting novel food. However, most studies investigating changes in dietary breadth focus on generalist species and do not delve into potential individual predictors of dietary wariness and the social factors modulating these responses. We investigated dietary wariness in the Gouldian finch, a dietary specialist, that is expected to avoid novel food. This species occurs in two main head colors (red, black), which signal personality in other contexts. We measured their initial neophobic responses (approach attempts before first feed and latency to first feed) and willingness to incorporate novel food into their diet (frequency of feeding on novel food after first feed). Birds were tested in same-sex pairs in same and different head color pairings balanced across experiments 1 and 2. Familiar and novel food (familiar food dyed) were presented simultaneously across 5 days for 3 h, each. Gouldian finches fed on the familiar food first demonstrating food neophobia, and these latencies were repeatable. Birds made more approach attempts before feeding on novel than familiar food, particularly red-headed birds in experiment 1 and when partnered with a black-headed bird. Individuals consistently differed in their rate of incorporation of novel food, with clear differences between head colors; red-headed birds increased their feeding visits to novel food across experimentation equaling their familiar food intake by day five, while black-headed birds continually favored familiar food. Results suggest consistent among individual differences in response to novel food with red-headed birds being adventurous consumers and black-headed birds dietary conservatives. The differences in food acceptance aligned with responses to novel environments on the individual level (found in an earlier study) providing individuals with an adaptive combination of novelty responses across contexts in line with potential differences in movement patterns. Taken together, these novelty responses could aid in population persistence when faced with environmental changes.

Salience Beats Individual Cue Preferences

“…While Gouldian Finches do not show a general preference for feature or spatial cues, individual preferences might be affected by the specific characteristics of a bird. Prediction 2a entailed that head colour morphs, which represent resident or nomadic cognitive styles, respectively, affect cue preferences, with black-headed birds potentially going for feature cues and red-headed birds for spatial cues [34,35]. However, no effects of head colour/cognitive style on cue preference were found.…”

“…Red-headed Gouldian Finches are more aggressive but less explorative, while black-headed birds are less aggressive but more explorative [33]. Moreover, a recent study about the cognitive differences between Gouldian Finches suggested that blackheaded birds invest more in local exploration and information gathering, resembling a resident cognitive style, while red-headed birds are better equipped for the exploration of larger areas, resembling a migratory/nomadic cognitive style [34,35]. However, little is known about the influence of the morphs on foraging strategies in Gouldian Finches.…”

Watch out! High vigilance at small waterholes when alone in open trees

“…Head colour signals the bird’s personality. Black-headed birds are less aggressive than red-headed birds and explore changes in their familiar environment quickly [ 48 , 49 ], whereas red-headed birds are more likely to venture into new environments and accept new food faster [ 50 , 51 ]. Moreover, black-headed females are bolder at waterholes than all other birds and take the lead when descending to drink [ 52 ].…”

Enclosure Background Preferences Differ between Sexes and Color Morphs in the Gouldian Finch

“…Red-headed birds are more aggressive [ 47 , 48 , 49 ] but take less risk in potentially dangerous situations and are less explorative of changes in their environment than black-headed birds [ 49 , 50 ]. However, red-headed birds enter unfamiliar environments faster and accept novel food quicker than black-headed birds [ 51 , 52 ]. Earlier experiments on background matching have shown that Gouldian finches prefer a simple green background over a patterned multi-color background [ 33 ].…”