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I show cases of atypical molt in the primaries of Harris's Hawk (Punihuteo unicinctus harrisi). Molt of the primaries in accipitrid raptors typically proceeds sequentially one feather at a time from the inner primary, PI. to the outer primary, P10. In larger species, not all primaries are replaced annually, resulting in Staffelmauser ('stepwise' or 'relay' molt). From 2002 to 2022.1 captured 545 Harris's Hawks in south Texas, either undergoing or having finished third prebasic molt or older, undergoing the second prebasic molt, or in Basic II plumage. 1 report herein on 6 instances in which 1 or more primaries were skipped or replaced out of order during the annual molt in Harris's Hawk: 5 undergoing the second prebasic molt and 1 undergoing third prebasic molt. I found 1 published case of skipped primaries in Griffon Vultures (Gyps fulvus) and another in a White Stork (Ciconia ciconia). One possible cause of this could be damaged primary follicles. Received II March 2022. Accepted 17 September 2022. Key words: out-of-order primary molt, skipped primary molt. Muestro casos de muda atipica en las primarias del halcon Parabuteo unicinctus harrisi. La muda de las primarias en rapaces accipitridos procede tipicamentc de manera secuencia!. una pluma a la vez a partir de la primaria interna. PI, hacia la primaria externa. PIO. En las especies mas grandes. no todas las primarias son rccmplazadas anualmente. lo que resulta en una Staffelmauser (muda 'por etapas' o 'relevos'). Del 2002 al 2022, capture 545 halcones de Harris en el sur de Texas, ya sea que estaban durante o al final de su tercera muda prcbasica o de mas edad, que esten realizando la segunda muda prcbasica o que esten en el plumaje basico II. Aqui reporto 6 instancias en las que 1 o mas primarias fueron sahadas o reemplazadas en desorden durante la muda anual en halcones de Harris: 5 durante la segunda muda prehasica y I durante la tercera muda prebasica. Encontre 1 repone publicado de primarias saltadas en buitrcs Gyps tubus y otro en cigiienas Ciconia ciconia. Una posiblc causa de esto serian foliculos primarios danados. Palabras clave: muda primaria desordenada. salto de muda primaria., Molt of the primaries in accipitrid raptors begins with the innermost feather (PI; primary molt center) every annual molt cycle. Molt proceeds sequentially in a wave with the next primary, [...]

An adult Buteo was found dead as a road-kill south of Sacramento, California, and was thought to represent the first state record of the eastern Red-shouldered Hawk (B. lineatus lineatus;). It is now a specimen in the Museum of Wildlife and Fisheries Biology (WFB 4816) at the University of California, Davis. We examined this specimen and found that many of its plumage characters differed from all other adult Red-shouldered Hawks examined, including nominate adults. Plumage markings and measurements were intermediate between Red-tailed Hawk (Buteo jamaicensis, ssp calurus) and Red-shouldered Hawk (ssp elegans), leading us to hypothesize that the bird was a hybrid. However, mtDNA sequences and nuDNA microsatellites proved definitively that the bird was a Red-shouldered Hawk, most likely of eastern origin. This case illustrates that apparent hybrids or apparent vagrants could be individuals with anomalous phenotypes caused by rare genetic variation or novel epigenetic effects.

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We studied the natural history of Gray Hawks (Buteo plagiatus) in the Lower Rio Grande Valley of Texas. We used GPS-GSM telemetry to quantify dispersal time and distance, winter home range size of juveniles, and home range size of adults. Home ranges were calculated using the kernel Brownian bridge home range estimator. The median dispersal date for 14 juvenile Gray Hawks was 11 August and they traveled a median straight-line distance of 453 km. Mean winter home range sizes for 11 juveniles was 707 ha. For juveniles, female winter home ranges were larger than those of males, and juvenile winter home ranges were larger in natural than in urban areas. Mean 95% home range sizes for 20 adult Gray Hawks was 530 ha. Mean adult male home range size was larger in natural than in urban areas. Adult Gray Hawks remained in their home ranges year-round. Estudiamos la historia natural de Buteo plagiatus en el Valle Inferior del Río Grande de Texas. Utilizamos telemetría GPS-GSM para cuantificar el tiempo y la distancia de dispersión, el tamaño del área de campeo de los juveniles en invierno y el tamaño del área de campeo de los adultos. Las áreas de campeo se calcularon utilizando el estimador de puentes brownianos del método kernel. La fecha mediana de dispersión de 14 juveniles de B. plagiatus fue el 11 de agosto y recorrieron una distancia mediana en línea recta de 453 km. El tamaño medio del área de campeo de invierno para 11 juveniles fue de 707 ha. Considerando los juveniles, las áreas de campeo de invierno de las hembras fueron más grandes que las de los machos, y las áreas de campeo de invierno de los juveniles fueron más grandes en las áreas naturales que en las urbanas. El tamaño medio del 95% del área de campeo para 22 adultos de B. plagiatus fue de 526 ha. El tamaño promedio del área de campeo de los machos adultos fue mayor en las áreas naturales que en las urbanas. Los adultos de B. plagiatus permanecieron en sus áreas de campeo durante todo el año. [Traducción del equipo editorial] [ABSTRACT FROM AUTHOR]