Surface texture and priming play important roles in predator recognition by the red-backed shrike in field experiments

Abstract

We compared the responses of the nesting red-backed shrikes (Lanius collurio) to three dummies of a common nest predator, the Eurasian jay (Garrulus glandarius), each made from a different material (stuffed, plush, and silicone). The shrikes performed defensive behaviour including attacks on all three dummies. Nevertheless, the number of attacks significantly decreased from the stuffed dummy through the plush dummy and finally to the silicone dummy. Our results show that wild birds use not only colours but also other surface features as important cues for recognition and categorization of other bird species. Moreover, the silicone dummy was attacked only when presented after the stuffed or plush dummy. Thus, we concluded that the shrikes recognized the jay only the stuffed (with feathered surface) and plush (with hairy surface) dummies during the first encounter. Recognition of the silicon dummy (with glossy surface) was facilitated by previous encounters with the more accurate model. This process resembles the effect of perceptual priming, which is widely described in the literature on humans.

The nest defence by the red‐backed shrikeLanius collurio– support for the vulnerability hypothesis

“…In our previous studies (Strnad et al 2012, Němec and Fuchs 2014, Němec et al 2015, Syrová et al 2016, we have shown that the red-backed shrike actively defends its nestlings against the stuffed dummies of selected types of predators when there are nestlings in the nest. Therefore, it is an ideal model species for testing the above mentioned hypotheses on the parental nest defence.…”

“…Each pair of shrikes was gradually exposed to all of the dummies (see above) in random order within one day. This arrangement should eliminate the effect of a possible positive reinforcement of defence during repeated presentations of dummies at the nest (Knight and Temple 1986, Redondo 1989, Němec et al 2015. Every experiment with one dummy lasted 20 min, followed by an hour break to let parents feed their nestlings and calm down.…”

Five species of passerine bird differ in their ability to detect Batesian mimics

“…The search image may also affect the ability of a bird to recognize other prey; in our case, the Batesian mimic. This is in concordance with a previous study showing that passerines can use search images to recognize dangerous animals, such as predators (Němec et al ., ). Our results show that the ability to develop a search image and the effect of the search image on the recognition of the Batesian mimic is very similar in predator species differing in their diet specialization.…”

Sparrowhawk movement, calling, and presence of dead conspecifics differentially impact blue tit (Cyanistes caeruleus) vocal and behavioral mobbing responses

“…Visual cues tend to travel over shorter distances than auditory cues and provide a relatively narrow field of detection (Stevens 2013 ), but are also important in recognizing and categorizing predators. Animals assess predator threat using a variety of visual cues, ranging from a predator’s body shape (Cook et al 2013 ), beak and eye shape (Beránková et al 2014 ), coloration (Davies and Welbergen 2008 ), and texture (Němec et al 2014 ). For example, Němec et al ( 2014 ) found that nesting red-backed shrikes ( Lanius collurio ) mob Eurasian jay ( Carrusul glandarius ) dummies when placed near their nest, but they responded most strongly to stuffed taxidermy jays, less strongly to plush toy jays, and least strongly to silicone dummies.…”