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

Abstract

Background: 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. Results: 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. Conclusions: 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.

Age-dependent effects of predation risk on night-time hypothermia in two wintering passerine species

“…Olfactory cues have routinely been used to assess the responses to perceived predation risk in studies on passerines. In the majority of these studies, birds respond to a predatory scent by avoidance (Amo et al 2008, 2011a, b, 2015, 2017; Mönkkönen et al 2009; but see Godard et al 2007; Johnson et al 2011). For example, breeding blue tits become increasingly vigilant, i.e., delay their entry into the nest box and decrease the time spent inside the nest box during feeding when exposed to predatory olfactory cues (ferret) (Amo et al 2008) in a largely similar manner as when exposed to visual predator cues (Amo et al 2017).…”

Egg concealment is an antipredatory strategy in a cavity‐nesting bird

“…To test whether egg covering is an antipredatory strategy in blue tit, we increased the perceived risk of predation by adding predator scent inside the nest boxes during the laying period. Many prey species can detect predator chemical cues and use them to assess the level of predation risk (Kats & Dill, ), including birds (Amo, Galván, Tomás, & Sanz, ; Amo, López‐Rull, Pagán, & Macías‐Garcia, ; Amo, Visser, & van Oers, ; Eichholz, Dassow, Stafford, & Weatherhead, ; Roth, Cox, & Lima, ; Zidar & Lovlie, ), and including blue tits (Amo et al, ). Therefore, predator chemical cues can be used to simulate an increase in the perceived risk of predation.…”

Wild great and blue tits do not avoid chemical cues of predators when selecting cavities for roosting

“…It was also shown that blue tits did not decrease the provisioning rate to nestlings, but they decreased the time devoted to other activities not essential for nestling survival such as nest sanitation activities [ 26 ]. Other species have also been shown to avoid predator chemical cues in a foraging context, such as the house finch, Carpodacus mexicanus [ 27 , 28 ] and the domestic fowl, Gallus gallus domesticus [ 29 ]. Birds can also avoid nesting in areas containing predator scent, as Anas sp.…”