Experimental analysis of novelty responses in a bird assemblage inhabiting a suburban marsh

Abstract

Suburban areas in the Pampas region of Argentina are inhabited by several bird species that sharply differ in their ability to exploit human-modified, urban areas. This bird assemblage includes species restricted to natural grasslands (e.g., Great Pampa Finch, Embernagra platensis (J.F. Gmelin, 1789)) as well as generalist, highly cosmopolitan species such as House Sparrow, Passer domesticus (L., 1758). We explored the role of certain aversive responses to novelty in shaping the marked differences in ecological plasticity among species in the assemblage. In field experiments, we tested for differences in feeding in the presence of artificial objects near feeders regularly replenished with seeds. In spite of their granivorous diet, some non-urbanized species did not use the feeders, possibly because of an extreme degree of aversion to novel situations. The group of birds that visited the feeders included both urbanized (N = 8) and non-urbanized (N = 2) species. We found that the presence of novel objects discouraged visitation to an otherwise attractive food source, although neophobia was weak for most species. However, we found unexpectedly high levels of neophobia in highly generalist, urbanized species such as House Sparrow and Shiny Cowbird, Molothrus bonariensis (J.F. Gmelin, 1789). This response is discussed in the context of the influence of post-fledging development in a relatively simple and predictable ecosystem versus that in urban areas.

Innovativeness and the effects of urbanization on risk-taking behaviors in wild Barbados birds

“…Some of these mixed results may be due to local variation in species composition, urbanization history, human behavior and habitat structure. Such local effects might be strong in studies examining limited sets of species in restricted areas like Barbados (our experiments), Mar del Plata (Echeverría and Vassallo 2008), the Argentinian Pampas (Echeverría et al 2006), Jerusalem (Kark et al 2007), Seattle (Clucas and Marzluff 2015), or Berlin (Meffert and Dziock 2013;Clucas and Marzluff 2015). Global studies of the type done by Sol and colleagues (e.g., Sol et al 2005Sol et al , 2012Sol et al , 2014 may be needed to factor out variation due to local effects and achieve a comprehensive understanding of the relationships between urbanization, novelty responses and innovation.…”

“…Many of these behavioral changes imply adjustments of risk-taking behaviors, whereby urban populations tend to be less risk-averse than rural ones. For instance, urban Barbados bullfinches Loxigilla barbadensis are bolder than their rural counterparts , and the neophobia of a bird assemblage in the Pampas region in Argentina is higher in suburban compared to urban areas (Echeverría et al 2006). Similarly, within species, flight distances from humans decrease in urban compared to rural areas (Møller 2008b;Samia et al 2015a, b).…”

Dusting-off the file: A review of knowledge on urban ornithology in Latin America

“…Leveau (2008) also recorded that House Sparrows (Passer domesticus) alter their visiting rate to nectar-rich plants in relation to changes in human activity patterns and to the distribution of plants. Echeverría et al (2006) and Echeverría and Vassallo (2008) found that the presence of alien objects near feeding stations reduced feeding visitation rates to an otherwise attractive food source. Finally, Pinheiro (2003) evaluated the discriminatory behavior of birds to mimetic and non-mimetic butterflies among natural and urban habitats, concluding that discriminatory behavior is determined by the habitat in which birds live.…”

“…In Latin America, studies have concentrated on bird feeding behavior (Levin et al, 2000;Pinheiro, 2003;Echeverría et al, 2006;Echeverría and Vassallo, 2008). In contrast, studies performed in temperate zones and Australia focus on the behavioral responses of birds to human disturbance and urbanization (Fernández-Juricic et al, 2001;Chace and Walsh, 2006), and compare predator activities between edge and interior urban woodlands (Anderson and Burgin, 2008).…”

Experimental assessment of problem solving by Milvago chimango (Aves: Falconiformes)

“…In this regard, the noose carpet trap used in this work may be regarded as a novel object or feeding place (Coleman and Wilson 1997). This risk-prone behaviour of juveniles, in addition to a low neophobia, is more relevant in species with greater ecological plasticity (Greenberg 1990;Heinrich 1995; although see Echeverría et al 2006) like M. chimango, and might explain the short time to approach and contact the Plexiglas box during the experiments.…”