Migratory New World Blackbirds (Icterids) Are More Neophobic than Closely Related Resident Icterids

Abstract

Environments undergo short-term and long-term changes due to natural or human-induced events. Animals differ in their ability to cope with such changes which can be related to their ecology. Changes in the environment often elicit avoidance reactions (neophobia) which protect animals from dangerous situations but can also inhibit exploration and familiarization with novel situations and thus, learning about new resources. Studies investigating the relationship between a species’ ecology and its neophobia have so far been restricted to comparing only a few species and mainly in captivity. The current study investigated neophobia reactions to experimentally-induced changes in the natural environment of six closely-related blackbird species (Icteridae), including two species represented by two distinct populations. For analyses, neophobic reactions (difference in number of birds feeding and time spent feeding with and without novel objects) were related to several measures of ecological plasticity and the migratory strategy (resident or migratory) of the population. Phylogenetic relationships were incorporated into the analysis. The degree of neophobia was related to migratory strategy with migrants expressing much higher neophobia (fewer birds feeding and for a shorter time with objects present) than residents. Furthermore, neophobia showed a relationship to diet breadth with fewer individuals of diet generalists than specialists returning when objects were present supporting the dangerous niche hypothesis. Residents may have evolved lower neophobia as costs of missing out on opportunities may be higher for residents than migrants as the former are restricted to a smaller area. Lower neophobia allows them approaching changes in the environment (e.g. novel objects) quickly, thereby securing access to resources. Additionally, residents have a greater familiarity with similar situations in the area than migrants and the latter may, therefore, initially stay behind resident species.

Cognitive ecology: ecological factors, life‐styles, and cognition

“…Particularly in birds it has been shown that residents explore more than closely related migrants . Similarly, residents are less neophobic to feed beside a novel object than migrants . Both, high neophilia and low neophobia help residents to find and exploit new resources over the year.…”

Cautious Crows: Neophobia in Torresian Crows (Corvus orru) Compared with Three Other Corvoids in Suburban Australia

“…; Echeverría & Vassallo ) and has been supported by investigations into wild birds by Mettke‐Hofmann et al. (). Corvids have been frequently recorded as being wary of unfamiliar items or food types new to the bird's experience (Heinrich ), with Kijne & Kotrschal (, p13) stating that common ravens ( Corvus corax ) often take ‘minutes to months’ before they become familiar with a novel object.…”

“…), while fewer have been conducted on wild animals (Mettke‐Hofmann et al. ; Vernelli ). Experiments undertaken by Greenberg (, ) comparing neophobia in swamp ( Melospiza georgiana ) and song sparrows ( Melospiza melodia ) produced contradictory results among wild and captive birds, suggesting that certain experiences in the lives of young wild swamp sparrows increased their neophobia while this was not the case in song sparrows.…”

Background Predation Risk and Learned Predator Recognition in Convict Cichlids: Does Risk Allocation Constrain Learning?

“…However, predation pressure is often spatially and temporally variable (Sih et al 2000;Stankowich & Blumstein 2005), forcing prey to make behavioural decisions in the absence of complete information (ecological uncertainty; Dall et al 2005;McNamara & Dall 2010;Mathot et al 2012). Given that environments may change in an unpredictable fashion due to natural and human-induced factors, the question of how prey adjust to uncertainty in local predation risk has come to the forefront of research on antipredator decision-making (Mettke-Hofmann et al 2013;Mettke-Hofmann 2014).…”

“…The dangerous niche hypothesis(Greenberg & Mettke-Hofmann 2001;Mettke-Hofmann et al 2013) posits that prey faced with increased risk (predation risk, competition, unknown foraging opportunities) could reduce the costs associated with 'making a bad decision' by exhibiting increased neophobia. Degrees of freedom = 2, 71 McNamara & Dall 2010).…”