Evidence that the house finch (Carpodacus mexicanus) uses scent to avoid omnivore mammals

Luisa Amo,Constantino Macías García,Iluminada Pagán,Isabel López-Rull

doi:10.1186/s40693-015-0036-4

Abstract

The detection of predator chemical cues is an important antipredatory behaviour as it allows an early assessment of predation risk without encountering the predator and therefore increases survival. For instance, since chemical cues are often by-products of metabolism, olfaction may gather information not only on the identity but also about the diet of predators in the vicinity. Knowledge of the role of olfaction in the interactions of birds with their environment, in contexts as important as predator avoidance, is still scarce. We conducted two two-choice experiments to explore 1) whether the house finch Carpodacus mexicanus can detect the chemical cues of a marsupial predatory mammal, the common opossum (Didelphis marsupialis), and 2) whether its response to such cues is influenced by the recent diet of this omnivorous predator, as this would increase the accuracy with which the risk of predation is assessed. House finches avoided the area of the apparatus containing the scent of the predator, and this effect did not depend on the recent diet (bait used to lace the traps) of the predator. Our results provide clear evidence that house finches detect and use the chemical cues of predators to assess the level of predation risk of an area and avoid it.

Highlights

The detection of predator chemical cues is an important antipredatory behaviour as it allows an early assessment of predation risk without encountering the predator and increases survival
It is clearly necessary to increase the knowledge about the ability of bird species to recognise chemical cues of predators and their capability to obtain information about the predator diet in order to accurately assess the risk of predation
Detection of chemical cues of a nest predator The scent of the experimental chamber determined whether birds avoid it or not (Z = −2.13, p = 0.03; Figure 2), as most birds avoided the experimental chamber, when it contained opossum scent (8/10), but not when it contained a novel scent (3/10)

Summary

Introduction

The detection of predator chemical cues is an important antipredatory behaviour as it allows an early assessment of predation risk without encountering the predator and increases survival. The first study that showed a clear antipredatory response to predator scent was performed with blue tits Cyanistes caeruleus in a reproductive context. Birds delayed their entry to the nest-box for longer when it contained predator scent than when a control scent was placed inside the nest-box. It is clearly necessary to increase the knowledge about the ability of bird species to recognise chemical cues of predators and their capability to obtain information about the predator diet in order to accurately assess the risk of predation

Methods

Results

Discussion

Conclusion