01926nas a2200193   4500008004100000245009400041210006900135520130600204653001401510653001701524653002101541653002001562653002101582653001801603653001701621100002901638700002401667856004101691       2019                        eng d00aHow Early Do Birds Start Chirping? Dawn Chorus Onset and Peak Times in a Neotropical City0 aHow Early Do Birds Start Chirping Dawn Chorus Onset and Peak Tim3 a<p>Urbanisation poses important challenges for animal communication. Avian dawn choruses are a prominent component of urban soundscapes and have received attention in recent urban ecology studies. Current evidence based on comparisons of urban and non-urban sites suggest that urbanisation is associated with earlier dawn chorus singing activity. However, this phenomenon remains mainly unexplored in tropical cities. We here assessed dawn chorus onset and peak times in two contrasting conditions of the urbanisation intensity gradient (i.e., intra-urban and peri-urban forested areas) of a Neotropical city, Xalapa in Mexico, assessing relationships with noise at sunrise and artificial light at night. We found no differences in dawn chorus onset or singing peak times when contrasting intra- and peri-urban areas. However, we found non-significant trends for earlier chorus onsets and peak times with increasing noise levels. Our results show no relationship between artificial light at night and dawn chorus timing, adding evidence to recent studies showing that light pollution does not seem to be determinant in the dawn choruses of tropical birds. Further research is needed to include a wider array of urbanisation conditions and drivers of the singing routines of urban tropical birds.</p>
10abehaviour10abioacoustics10abird assemblages10amorning singing10aperi-urban areas10aUrban ecology10aurbanisation1 aMarín-Gómez, Oscar, H.1 aMacGregor-Fors, Ian  uhttps://bio.acousti.ca/nl/node/5839502352nas a2200205   4500008004100000245010300041210006900144520163500213653001901848653002501867653001501892653002701907653001801934100002901952700002101981700002502002700002802027700002402055856006702079       2020                        eng d00aWhere has the city choir gone? Loss of the temporal structure of bird dawn choruses in urban areas0 aWhere has the city choir gone Loss of the temporal structure of 3 a<p>Living in the city represents a great challenge for organisms that are exposed to the novel environmental conditions inherent to urbanization. Recent studies have highlighted the ecological impact that urbanization poses on the acoustic phenotype and singing routines of birds. However, the organization and structure of avian dawn choruses in urban settings remains largely unexplored. In this study, we assessed the temporal structure of avian dawn choruses in an intra-urban area and a peri-urban forest using bipartite network analyses. We predicted a random network structuring of dawn choruses across time at the intra-urban area, while expected a non-random structure (i.e., modular or nested) at the peri-urban forest. While we detected different groups of birds vocalizing together temporarily, following a modular pattern in both studied conditions, only the one from the peri-urban forest showed a sequential temporal structure of dawn choruses. Avian dawn choruses from both intra-urban and peri-urban areas were mainly comprised by phylogenetically unrelated species (i.e., random phylogenetic structure), also exhibiting low overlap on singing frequencies. Our results are in agreement with the temporal partitioning of the acoustic space in the peri-urban forest. Our findings also suggest that the absence of temporally-structured modules of bird dawn choruses at heavily-urbanized areas could be related to the depauperization of the avian community at intra-urban areas as a sequel of ecological filtering, as well as the consequent importance of the dominance of the acoustic space by invasive species.</p>
10aAcoustic space10aEcological filtering10aModularity10aMulti-species choruses10aUrban ecology1 aMarín-Gómez, Oscar, H.1 aDáttilo, Wesley1 aSosa-López, Roberto1 aSantiago-Alarcon, Diego1 aMacGregor-Fors, Ian  uhttps://linkinghub.elsevier.com/retrieve/pii/S0169204618305322