Crows (Corvus corone ssp.) check contingency in a mirror yet fail the mirror-mark test.

Abstract

Mirror reflections can elicit various behavioral responses ranging from social behavior, which suggests that an animal treats its own reflection as a conspecific, to mirror-guided self-directed behaviors, which appears to be an indication for mirror self-recognition (MSR). MSR is scarcely spread in the animal kingdom. Until recently, only great apes, dolphins, and elephants had successfully passed this test. The range of convergence was, however, expanded by an avian species, the Eurasian magpie (Pica pica). Efforts to find MSR in other corvid species have so far failed, and with only a few studies conducted, the cause of these discrepancies is difficult to identify. In the present study, we examined the responses to mirrors and the ability of MSR in hitherto untested species: the carrion and hooded crows (Corvus corone ssp.). These crows showed a pronounced and lasting interest in the mirror; unlike many species, they did not exhibit social behaviors on their first encounters but immediately started investigating the mirror. Some crows showed contingent behaviors in front of the mirror, but none of the crows showed significant mirror-guided self-directed behaviors nor mark-directed behavior during the subsequent mark test. This lack of mark-directed behavior could not be explained by a lack of interest in the mirror nor in the mark. These findings could indicate that crows lack a concept of self, or the need for other means of investigating self-recognition and self-awareness in avian species.

Investigating Behavioral Responses to Mirrors and the Mark Test in Adult Male Zebra Finches and House Crows

“…Apart from increased mark-directed preening (discussed below), increases in mirror directed self-exploration (Povinelli et al, 1993), contingency behaviors (Ari and D'Agostino, 2016), concomitant decreases in aggressive behavior, conspecific search responses (Gallup, 1970) and vocalizations are also considered to be positive indicators of visual self-recognition. In our study, we found significant decreases in the time spent viewing the reflection in one zebra finch (Y45) and one crow (HC33), suggesting that they adapted to their reflections, which is also observed in other species of birds (Prior et al, 2008;Medina et al, 2011;Vanhooland et al, 2019). There were also clear decreases in social responses (vocalization) in two zebra finches (Y45 and Y48) and one crow (HC33).…”

“…These findings are also supported by the fact that house crows spent less time examining their reflections (∼27%). Whereas, our findings in house crows are comparable to those in jungle crows (Kusayama, Bischof, and Watanabe 2000), New Caledonian crows (Medina et al, 2011), carrion crows (Vanhooland et al, 2019;, and jackdaws (Soler et al, 2014), which did not display mirror directed self-exploration, a recent study (Buniyaadi et al, 2019) has demonstrated that house crows pass the mark test. However, there were a number of differences between their paradigm and ours.…”

“…A variety of avian species, namely New Caledonian crows (Medina et al, 2011), Eurasian Magpies (Prior et al, 2008), zebra finches (Ryan, 1978;Iyengar et al, 2017), jungle crows (Kusayama et al, 2000), African gray parrots (Pepperberg et al, 1995), pigeons (Uchino and Watanabe, 2014), Java Sparrows (Watanabe, 2002), jackdaws (Soler et al, 2014), Clark's nutcrackers (Clary and Kelly, 2016), great tits (Kraft et al, 2017), keas and Goffin's cockatoos (Buuren et al, 2018), carrion crows (Vanhooland et al, 2019;, and Indian house crows (Iyengar et al, 2017;Buniyaadi et al, 2019) have been tested for their responses to mirrors. The general principle underlying these studies is that mirror self-recognition is an example of a higher cognitive function which has emerged across different species through convergent evolution (Reiss and Marino, 2001;Prior et al, 2008).…”

“…Preliminary data from our lab had revealed that house crows appeared not to pass the mark test (Iyengar et al, 2017). Given the high degree of variability on the performance of corvids on the mark test (Prior et al, 2008;Soler et al, 2014;Buniyaadi et al, 2019;Vanhooland et al, 2019), we decided to perform a detailed examination of the performance on mirror self-recognition in house crows (Corvus splendens). Since zebra finches do not perform cognitively advanced tasks such as tool use, which has been observed in corvids such as New Caledonian crows (Kenward et al, 2006), we hypothesized that zebra finches would not pass the mark test.…”

If horses had toes: demonstrating mirror self recognition at group level in Equus caballus

“…Chi-square, p-values Sham Mark Chi-square, p-values Antonia 0.0 7.5 N/A 0.0 1.4 N/A Arramon 0.0 0.0 N/A 4.5 5.0 N/A Ercole 3.7 15.6 Χ 2 = 6.2; p = 0.013 17.1 20.3 Χ 2 = 0.1; p = 0.729 Falco2 3.7 7.0 Χ 2 = 0.5; p = 0.480 0.0 0.0 N/A King 0.0 5.0 N/A 3.7 0.0 N/A Nadijia 0.0 4.3 N/A 2.7 3.6 N/A Oliver 0.0 4.8 N/A 6.6 7.1 Χ 2 = 0.0; p = 1.000 Oti 0.0 5.1 N/A 21.3 5.5 Χ 2 = 8.2; p = 0.004 Serafine 4.0 0.0 N/A 0.0 5.0 N/A Shaif 1.1 9.0 Χ 2 = 4.7; p = 0.030 30.3 7.2 Χ 2 = 13; p < 0.001 Sunshine 1.7 10.1 Χ 2 = 4.6; p = 0.031 8.2 4.5 Χ 2 = 0.6; p = 0.446 during which the bird moved out and back in sight of the mirror (Soler et al 2014;Vanhooland et al 2019) and chimpanzees manipulated their lips and tongues while glancing into the mirror (Povinelli et al 1993). Our horses engaged in contingency behaviors similar to those reported for other species such as head movements, peek-a-boo, and tongue protrusion almost exclusively in presence of the reflective surface (Table 3).…”