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We discuss select imprecise and untenable natural history information about migration, urban habitat use, and diet presented in the technical literature about Accipiter hawks in North America. We focus primarily on challenging the claim that Sharp-shinned Hawks (Accipiter striatus) are more frequent predators of House Sparrows (Passer domesticus) than are Cooper's Hawks (A. cooperii). We urge scientists to be cognizant of the ever-changing dynamics of the predatory behavior, nesting, and migration ecology of Sharp-shinned and Cooper's hawks due to anthropogenic factors, features that are in constant flux and may not be well tracked long term or apply to the entire distributional ranges of these 2 species. Discutimos acerca de informaciones de historia natural imprecisa e insostenible acerca de la migración, del uso de hábitat urbano y la dieta presentada en la literatura técnica sobre gavilanes Accipiter en América del Norte. Principalmente nos enfocamos en cuestionar la afirmación de que el gavilán americano (Accipiter striatus) es un depredador más frecuente de gorrión común (Passer domesticus) que del gavilán de Cooper (A. cooperii). Exhortamos a los científicos a reconocer las dinámicas siempre cambiantes de comportamientos de depredación, anidamiento y ecología migratoria del gavilán americano y del gavilán de Cooper debido a factores antropogénicos, aspectos que están en flujo constante y podrían no tener buen seguimiento a largo plazo o no aplicar al rango de distribución completo de esas especies. Palabras clave: depredación, dieta, gorrión común, migración, urbanización. [ABSTRACT FROM AUTHOR]

Abstract: Developing useful biological isoscapes for areas of the world is a priority. This is the case for Mexico that hosts a large percentage of North America''s Neotropical migrant birds. Here we investigated the use of House Sparrow (Passer domesticus) feathers to create a spatially explicit feather deuterium isoscape for that country using samples (n =461) that were collected across Mexico. Considerable and useful spatial hydrogen isotopic structure was observed, suggesting that isotopes may be a potential forensic tool for evaluating origins of Mexican derived fauna and flora. The most positive feather δD values occurred in the northeast and most negative in the south-central part of the country, roughly matching δD patterns observed in groundwater. A weak negative isotopic relationship was found with altitude in both the Pacific and Atlantic drainage systems. The most parsimonious model describing isotopic spatial variation in feathers between 300 and 3000 m a.s.l. included groundwater δD (δD gw; precipitation proxy), sex, amount of precipitation, and the coefficient of variation in amount of precipitation. Overall, δD gw was a poor predictor of sparrow δD f values for all of Mexico. However, this relationship was considerably strengthened when we considered sex separately, removed the Baja peninsula from our sample, and considered the Atlantic and Pacific drainage basins separately. The strongest relationship between δD gw and δD f was found for female sparrows in the Atlantic drainage basin (r 2 =0.464). We recommend that researchers interested in inferring origins of migratory birds and other animals in Mexico create species specific isotopic basemaps that may be guided by the isotopic patterns we have observed for House Sparrows and groundwater. [Copyright &y& Elsevier]