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Avian beaks are complex and highly specialized structures that if altered could hinder many aspects of bird biology. Here, we provide evidence from incidental sightings of 24 birds from 9 species presenting a mild to severe degree of beak abnormality, including species from Passeriformes, Falconiformes, Sphenisciformes, and Charadriiformes, recorded in Chile (2013-2016). The most common alterations corresponded to crossed beaks and excessive elongation of the upper beak (25% each). The Austral Thrush (Turdus Jalcklandii; n = 11) and Chilean Mockingbird (Mimus thenca; n = 5) were the birds most frequently recorded with abnormalities. With the exception of the Austral Thrush and Magellanic Penguin (Spheniscus magellanicus), all beak abnormalities mentioned here are the first recorded for each species. Received 11 August 2017. Accepted 18 September 2018.

The Sturnidae family comprises 123 recognized species in 35 genera. The taxa Mimidae and Buphagidae were formerly treated as subfamilies within Sturnidae. The phylogenetic relationships among the Sturnidae and related taxa (Sturnidae sensu lato) remain unresolved due to high rates of morphological change and concomitant morphological homoplasy. This study presents five new mitogenomes of Sturnidae sensu lato and comprehensive mitogenomic analyses. The investigated mitogenomes exhibit an identical gene composition of 37 genes—including 13 protein-coding genes (PCGs), 2 rRNA genes, and 22 tRNA genes—and one control region (CR). The most important finding of this study is drawn from CAM analyses. The surprisingly unique motifs for each species provide a new direction for the molecular species identification of avian. Furthermore, the pervasiveness of the natural selection of PCGs is found in all examined species when analyzing their nucleotide composition and codon usage. We also determine the structures of mt-tRNA, mt-rRNA, and CR structures of Sturnidae sensu lato. Lastly, our phylogenetic analyses not only well support the monophyly of Sturnidae, Mimidae, and Buphagidae, but also define nine stable subclades. Taken together, our findings will enable the further elucidation of the evolutionary relationships within Sturnidae sensu lato.

Landscape connectivity is a key factor determining the viability of populations in fragmented landscapes. Predicting 'functional connectivity', namely whether a patch or a landscape functions as connected from the perspective of a focal species, poses various challenges. First, empirical data on the movement behaviour of species is often scarce. Second, animal-landscape interactions are bound to yield complex patterns. Lastly, functional connectivity involves various components that are rarely assessed separately. We introduce the spatially explicit, individual-based model FunCon as means to distinguish between components of functional connectivity and to assess how each of them affects the sensitivity of species and communities to landscape structures. We then present the results of exploratory simulations over six landscapes of different fragmentation levels and across a range of hypothetical bird species that differ in their response to habitat edges. i) Our results demonstrate that estimations of functional connectivity depend not only on the response of species to edges (avoidance versus penetration into the matrix), the movement mode investigated (home range movements versus dispersal), and the way in which the matrix is being crossed (random walk versus gap crossing), but also on the choice of connectivity measure (in this case, the model output examined). ii) We further show a strong effect of the mortality scenario applied, indicating that movement decisions that do not fully match the mortality risks are likely to reduce connectivity and enhance sensitivity to fragmentation. iii) Despite these complexities, some consistent patterns emerged. For instance, the ranking order of landscapes in terms of functional connectivity was mostly consistent across the entire range of hypothetical species, indicating that simple landscape indices can potentially serve as valuable surrogates for functional connectivity. Yet such simplifications must be carefully evaluated in terms of the components of functional connectivity they actually predict.

Studies of community organization and clade diversification that include functional traits have become an important component of the analysis of ecological and evolved systems. Such studies frequently are limited by availability of consistently collected data. Here, I present a data set including eight measurements of the external morphology of 1642 species, roughly one-quarter of all passerine birds (Aves: Order Passeriformes), from all parts of the world, characterizing the relative proportions of the wing, tail, legs, and beak. Specimens were measured opportunistically over the past 40 years in museums in the United States and Europe. Numbers of individuals measured per species vary from one to dozens in some cases. Measurements for males and females of sexually size-dimorphic species are presented separately. The measurements include total length, the lengths of the wing, tail, tarsus, and middle toe, and the length, breadth, and depth of the beak. Particular attention was paid to obtaining a broad representation of passerine higher taxa, with special interest in small families and subfamilies of passerines, as well as species produced by evolutionary radiations of birds in archipelagoes, including the Galapagos, Hawaii, and the Lesser Antilles. Taxonomy follows the Taxonomy in Flux (TIF) checklist as well as the World Bird List of the International Ornithological Council. Geographic distributions are summarized from Edwards's Coded List of Birds of the World. Coverage of taxa and geographic regions varies and reflects the changing interests of the author over the past four decades. North American and South American species are particularly well represented in the sample, as well as species belonging to the families Tyrannidae, Furnariidae, Thamnophilidae, Mimidae, Sturnidae, Fringillidae, Parulidae, Icteridae, Cardinalidae, and Thraupidae.

Social behaviors can significantly affect population viability, and some behaviors might reduce extinction risk. We used population viability analysis to evaluate effects of past and proposed habitat loss on the White-breasted Thrasher (Ramphocinclus brachyurus), a cooperatively breeding songbird with a global population size of <2000 individuals. We used an individual-based approach to build the first demographic population projection model for this endangered species, parameterizing the model with data from eight years of field study before and after habitat loss within the stronghold of the species' distribution. The recent habitat loss resulted in an approximately 18% predicted decline in population size; this estimate was mirrored by a separate assessment using occupancy data. When mortality rates remained close to the pre-habitat loss estimate, quasi-extinction probability was low under extant habitat area, but increased with habitat loss expected after current plans for resort construction are completed. Post-habitat loss mortality rate estimates were too high for projected populations to persist. Vital rate sensitivity analyses indicated that population growth rate and population persistence were most sensitive to juvenile mortality. However, observed values for adult mortality were closest to the threshold value above which populations would crash. Adult mortality, already relatively low, may have the least capacity to change compared to other vital rates, whereas juvenile mortality may have the most capacity for improvement. Results suggest that improving mortality estimates and determining the cause(s) of juvenile mortality should be research priorities. Despite predictions that aspects of cooperative systems may result in variation in reproduction or juvenile mortality being the most sensitive vital rates, adult mortality was the most sensitive in half of the demographic models of other avian cooperative breeders. Interestingly, vital rate sensitivity differed by model type. However, studies that explicitly modeled the species' cooperative breeding system found reproduction to be the most sensitive rate.

Congeneric species have similarities in phenotypic and ecological traits. The sympatry of congeneric species constitutes an opportunity for studies on coexistence. Two bird species of Mimidae, the native Tropical mockingbird, Mimus gilvus Oberho 1919, and the restinga invader Chalk-browed mockingbird, Mimus saturninus (Lichtenstein, 1823), currently occur in sympatry across the sandy-coastal ecosystem (restinga) of Espirito Santo state, Southeastern Brazil. We studied the spatial distribution of Tropical mockingbird and Chalk-browed mockingbird to understand the degree of competition across a preserved and urban gradient. We sampled 1,451 sampling units across a preserved and urban landscape in a coastal area of southeastern Brazil. The best-fitting model for abundance (Punctual Abundance Index) included urbanization index,distance from the coast, and distance from the closest protected area, which explained 63% and 97% of the abundance of Tropical mockingbird and Chalk-browed mockingbird, respectively. The species exhibited a segregated spatial pattern at small scale, indicating that both species are avoiding one another. Chalk-browed mockingbird showed ecological plasticity in modified environments, whereas Tropical mockingbird was more sensitive to urbanization. We suggested thatthe coexistence of these species is associated with resource partitioning. Monitoring Tropical mockingbird populations may be a proxy for the assessment of habitat quality and restoration success in the highly threatened restinga ecosystem.

The role of Quaternary glacial–interglacial intervals in shaping the diversity and distribution of Neotropical species has been the focus of considerable research. The Neotropics sustain the highest passerine diversity on Earth, but little is known about this region's historical biogeography based on fossils. To assess how passerine species were affected by Quaternary climate fluctuations, we identified 625 late Pleistocene fossils (individual fossilized bones) from the now arid and faunally depauperate Talara Tar Seeps in northwestern Peru. Of the 21 passerine species identified, only 2 likely live at the site now; the remaining 19 species require more mesic conditions. Species identified included members of the Thamnophilidae (antbirds), Melanopareiidae (crescentchests), Tyrannidae (flycatchers), Hirundinidae (swallows), Mimidae (mockingbirds), Thraupidae (seedeaters, “finches”), Emberizidae (sparrows), and Icteridae (blackbirds). Nearly half of the individual fossils and 8 of the 21 species were icterids, including 3 extinct species (1 previously described, 2 new). The late Pleistocene passerine community at Talara, which was nonanalog to any modern community, suggests that the site once supported savanna, grasslands, and forests during the last glacial interval, which are absent near Talara today. Quaternary climate change and the collapse of the community of large mammals had a major influence on the community composition and the geographic ranges of passerine species in northwestern Peru.

Northern Mockingbirds (Mimus polyglottus) were studied between 1995 and 2015 on a university campus in New Orleans, U.S.A., spanning the 2005 landfall of Hurricane Katrina. The storm subjected the city to high winds and a prolonged flood. Nesting success showed a spike for 3 y after the storm, after which it gradually sank back to near pre-storm levels. Number of broods detected jumped from the first to the second year after the storm on campus and at two nearby residential sites. Success of males in acquiring mates improved from the first nesting season after the storm to the second across the three sites. Results draw attention to the importance of considering top-down effects in analyzing the recovery of storm-impacted birds.

The alarm calls of many vertebrates encode predator-specific information such as the type of predator or the urgency of the threat. When an alarm call is only produced in a specific context and elicits specific behaviors from the recipients it is referred to as functionally referential. The pervasiveness of functionally referential alarm calls across bird species, however, remains to be established. In this study, we first classified Northern Mockingbird (Mimus polyglottos) alarm calls and then assessed if parental birds produced different alarm calls for different predators or nestling stages. To classify alarm calls we first isolated parental calls that preceded nest predation events from mockingbird nest camera footage and analyzed them using Raven Pro. Using a PCA analysis, we identified 9 different alarm calls based on 18 different predation events that resulted in 494 alarm calls given. To determine if the alarm calls were predator- or nest stage-specific we conducted a multinomial logistic regression. One call was given exclusively in association with snakes and 2 were given almost entirely in association with cats. In response to American Crows (Corvus brachyrhynchos), mockingbirds mainly produced a fourth alarm call, which was also frequently associated with Cooper's Hawks (Accipiter cooperii). The remaining 5 alarm calls were associated with Cooper's Hawks. While we have strong preliminary evidence for predator-specific alarm calls in nesting Northern Mockingbirds, many of these calls are also given in other contexts, such as in intraspecific interactions, which would exclude them from being considered functionally referential. These results highlight the challenges of categorizing alarm calls as functionally referential and the need to further integrate functional reference with context-dependent communication.

Some insectivorous avian species may improve foraging success by flashing conspicuously colored wing patches or tail spots to startle potential prey and elicit escape behavior. While some studies of Mimus polyglottos (Northern Mockingbird) suggest that wing-flashing (WF) behavior may enhance strike rate and/or foraging success, other studies are equivocal or suggest a negative relationship. Anecdotal observations suggest that WF in mockingbirds may serve an additional role, as this behavior has been documented in response to a potential predator. The biological roles of WF remain unclear in Northern Mockingbirds; thus, we sought to systematically study: (1) the seasonal use of WF while foraging, and (2) the behavioral response of mockingbirds when presented with 2 model organisms—a nest predator and a neutral avian species. We found that foraging bouts during the reproductive period were more likely to include WF than those during the non-reproductive period, but that there was no significant relationship between WF rate and either strike rate or foraging-success rate. When exposed to models, mockingbirds only employed WF during the reproductive period, and then, only to the predator model. Our results suggest that WF is confined primarily to the reproductive period of the annual cycle, and that this behavior is utilized while foraging and in response to the presence of a potential predator. However, the biological role WF plays in both of these circumstances bears further examination.