Phenology effects on productivity and hatching-asynchrony of American kestrels (Falco sparverius) across a continent

Climate-driven advances in spring can result in phenological mismatch between brood rearing and prey availability and consequently cause decreased productivity in birds. How consequences of mismatch vary across species' ranges, and how individual behavior can mitigate mismatch effects is less studied. We quantified the relationship between phenological mismatch, productivity, and behavioral adaptations of American kestrels (Falco sparverius) across their breeding range in the United States and southern Canada. We obtained phenology and productivity data using nest observations from long term nest box monitoring, remote trail cameras, and community-scientist based programs. We collected data on parental incubation behavior and hatch asynchrony using trail cameras in nest boxes. Kestrels that laid eggs after the start of spring had higher rates of nest failure and fewer nestlings than earlier nesters, and effects of mismatch on productivity were most severe in the Northeast. In contrast, kestrels in the Southwest experienced a more gradual decline in productivity with seasonal mismatch. We attribute the effect of location to the growing season and temporal nesting windows (duration of nesting season). Specifically, resource availability in the Northeast is narrow and highly peaked during the breeding season, potentially resulting in shorter nesting windows. Conversely, resource curves may be more prolonged and dampened in the Southwest, and growing seasons are becoming longer with climate change, potentially resulting in longer nesting windows. We found that the onset of male incubation was negatively associated with lay date. Males from breeding pairs that laid eggs after the start of spring began incubation sooner than males from breeding pairs that laid before the start of spring. Early-onset male incubation was positively associated with hatching asynchrony, creating increased age variation in developing young. In sum, we demonstrate that American kestrels are vulnerable to phenological mismatch, and that this vulnerability varies across space. Northeastern populations could be more vulnerable to mismatch consequences, which may be one factor contributing to declines of kestrels in this region. Also, we demonstrate early onset of incubation as a potential adaptive behavior to advance average hatch date and spread out offspring demands, but it is unknown how impactful this will be in mitigating the fitness consequences of phenology mismatch.

CONTRIBUIÇÃO AO ESTUDO DA AVIFAUNA DA PRAÇA FLÁVIO BOIANOVSKI, CAPÃO DA CANOA, LITORAL NORTE DO RIO GRANDE DO SUL

Introdução: Dentro de uma perspectiva de Ecologia Urbana, as aves constituem um importante grupo sinantrópico, uma vez que estabelecem com os humanos relações, em geral positivas, pois a aparência e o canto das aves são aprazíveis para os humanos e a facilidade em obter alimentos para as aves é satisfatória. As áreas arborizadas em ambientes urbanos, como as praças e parques, são locais relevantes de interação entre estes dois grupos. Objetivo: O objetivo do presente estudo foi catalogar as espécies que frequentam e/ou vivem na Praça Boianovski, localizada na cidade litorânea de Capão da Canoa, Rio Grande do Sul. Material e métodos: Foram realizadas observações mensais entre março de 2018 e agosto de 2020. Para realização da coleta de dados, foram percorridas as quatro primeiras quadras a partir do mar (29º75’64”S/50º01’12”W - 29º75’43”S/50º01’16”W), sendo estas as áreas mais arborizadas. São também as seções mais usadas por moradores e veranistas para tomar sol, praticar esportes (há quadras de vôlei e futebol de areia, canchas de bocha e equipamentos para ginástica) e para o lazer das crianças (pracinha e parque com infláveis). Resultados: As aves foram observadas tanto no turno da manhã quanto no da tarde com o uso de binóculo e identificadas com uso de guias específicos. Ao final de 29 meses foram catalogadas 29 espécies, pertencentes a nove ordens e 18 famílias. Nove espécies foram muito frequentes (mais de 70% das observações), quatro frequentes (50 e 69%), quatro pouco frequentes (30 a 49%) e 12 espécies raras (menos de 30%). Convém destacar que os falconiformes Falco sparverius, Milvago chimachima e Caracara plancus assim como a curicaca Theristicus caudatus, foram observados apenas em sobrevoo sobre a área, evidenciando a busca por alimento. Conclusão: Considerando-se que, esta é uma área de intensa movimentação humana, a avifauna residente (muito frequentes) parece estar bem adaptada a este ambiente, além desta área servir ainda para o forrageio de espécies circulantes.

Historical Accounts Provide Inference into Population Dynamics of American Kestrels (Falco sparverius) in the Northeastern USA

ABSTRACT American Kestrels (Falco sparverius) are declining across much of North America, yet the initial timing of the population decrease is unclear. In an attempt to elucidate when kestrel declines began, we examined historical descriptions of abundance within the northeastern United States. Within The Peregrine Fund's research library, we found 54 descriptions of kestrel abundance in northeastern states dating from 1839 to 2013. Our analysis indicates a cubic trend in descriptions of kestrel abundance with a peak occurring in 1951. After that peak, the population began its current decline, yet the population appears to have been stable beforehand. That the current decline is apparent in our data set lends credence to our methodology and suggests that populations were likely secure until approximately 1951. Our results thus suggest that populations of American Kestrels in the northeastern United States began declining before systematic monitoring began in 1966. Future research should thus examine what environmental changes occurred around the early- to mid-20th century in the northeastern USA to cause population declines of American Kestrels.

Prótesis 3D para corregir eje corporal y equilibro en lechuza de campanario y cernícalo americano

La amputación de miembros pélvicos en aves rapaces, debe ser evaluada con detenimiento y considerada como el último recurso para salvar la vida del ave, debido a que posterior a la amputación, pueden derivarse una serie de factores degenerativos, como la alteración de eje corporal, distribución inadecuada del peso corporal y pododermatitis. Una buena alternativa para contrarrestar estos problemas, es el uso de prótesis, que busquen recuperar el eje corporal y mantener una buena postura en el ave. El uso de impresoras 3D para este tipo de proyectos, ofrece una alternativa más accesible y sencilla debido a su versatilidad tanto en diseño como en materiales. El presente proyecto pone a prueba el diseño de una prótesis 3D y documenta la corrección de eje corporal e incorporación de la prótesis en las actividades diarias de un cernícalo americano (Falco sparverius) y una lechuza de campanario (Tyto alba), ambas con una amputación tibiotarsal en su tercio distal. A pesar de que la utilización de prótesis no permite la reintroducción de las aves al medio ambiente, ofrece una oportunidad para integrar dichas aves en programas de conservación, tales como reproducción en cautiverio o educación ambiental.

The American Kestrel (Falco sparverius) genoscape: implications for monitoring, management, and subspecies boundaries

Identifying population genetic structure is useful for inferring evolutionary process and comparing the resulting structure with subspecies boundaries can aid in species management. The American Kestrel (Falco sparverius) is a widespread and highly diverse species with 17 total subspecies, only 2 of which are found north of U.S./Mexico border (F. s. paulus is restricted to southeastern United States, while F. s. sparverius breeds across the remainder of the U.S. and Canadian distribution). In many parts of their U.S. and Canadian range, American Kestrels have been declining, but it has been difficult to interpret demographic trends without a clearer understanding of gene flow among populations. Here we sequence the first American Kestrel genome and scan the genome of 197 individuals from 12 sampling locations across the United States and Canada in order to identify population structure. To validate signatures of population structure and fill in sampling gaps across the U.S. and Canadian range, we screened 192 outlier loci in an additional 376 samples from 34 sampling locations. Overall, our analyses support the existence of 5 genetically distinct populations of American Kestrels—eastern, western, Texas, Florida, and Alaska. Interestingly, we found that while our genome-wide genetic data support the existence of previously described subspecies boundaries in the United States and Canada, genetic differences across the sampled range correlate more with putative migratory phenotypes (resident, long-distance, and short-distance migrants) rather than a priori described subspecies boundaries per se. Based on our results, we suggest the resulting 5 genetically distinct populations serve as the foundation for American Kestrel conservation and management in the face of future threats.