Mark S. Martell

EVIDENCE OF NOCTURNAL MIGRATION BY OSPREY (PANDION HALIAETUS) IN NORTH AMERICA AND WESTERN EUROPE

ABSTRACT Resumimos y discutimos observaciones recientes de migraciones nocturnas de Pandion haliaetus. En el otoño de 2004, desde la plataforma de observación (elevación 320 m) del edificio Empire State en la ciudad de Nueva York se realizaron dos avistamientos nocturnos de individuos migrando hacia el sur. De igual forma, el monitoreo satelital ha revelado que P. haliaetus migra durante la noche de manera regular tanto en la temporada migratoria de otoño como en la de primavera, particularmente en vuelos largos que implican el cruce de cuerpos de agua. Encontramos que 15 individuos migraron hacia el sur durante la noche en otoño (1) de Carolina del Norte a Florida, (2) de Florida a Cuba y (3) de Cuba a Centroamérica/México o América del Sur. En la migración hacia el norte, dos individuos migraron durante la noche desde Sudamérica hacia Cuba. Algunos de los vuelos sobre agua representaron entre 12–22 horas de vuelo continuo. También proveemos información que muestra que al menos otras 10 especies de rapaces migran durante la noche de manera regular.

THE SPRING MIGRATION OF ADULT NORTH AMERICAN OSPREYS

Abstract Most North American Ospreys (Pandion haliaetus) are migratory, breeding in northern latitudes and migrating long distances to and from their wintering grounds in the tropics. Although fall migration patterns of North American Ospreys have been described and studied, very little has been published about the spring migration of these birds. We used satellite telemetry to: (1) determine the characteristics (timing, duration, migratory routes) of spring migrations of Ospreys; (2) determine if differences in spring migration patterns existed between sexes and among three breeding populations (east coast, midwestern, and western); and (3) compare consecutive fall and spring migrations of individual Ospreys. The median dates for departure from the wintering grounds and arrival on the breeding grounds did not differ significantly between adult male and female Ospreys. Compared to their fall migrations, all male and all east coast Ospreys spent fewer days on migration, fewer days in stopover periods along the migration route, traveled shorter distances overall, and traveled farther (on average) each day during spring. In contrast, fall and spring migration characteristics of all female and western Ospreys were similar. Our findings suggest that, although sex and breeding location might influence the spring migration strategy used by individual Ospreys, both males and females minimize the time spent on migration to ensure a timely arrival on the breeding grounds to establish or defend a nesting territory. Migración Primaveral de Individuos Adultos de Pandion haliaetus La mayoría de los individuos de Pandion haliaetus son migratorios, reproduciéndose en latitudes hacia el norte y migrando largas distancias hacia y desde los sitios de invernada en los trópicos. Aunque los patrones de migración otoñal de P. haliaetus han sido descriptos y estudiados, se ha publicado muy poco sobre la migración primaveral de esta especie. Utilizamos telemetría satelital para: (1) determinar las características (tiempos, duración, rutas migratorias) de la migración primaveral de P. haliaetus; (2) determinar si las diferencias en los patrones de migración primaveral existieron entre sexos y entre tres poblaciones reproductivas (costa este, medio oeste y oeste); y (3) comparar migraciones consecutivas de otoño y primavera de individuos de P. haliaetus. Las fechas medianas de partida desde los sitios de invernada y de arribo a los sitios de reproducción no difirió significativamente entre individuos macho y hembra de P. haliaetus. En comparación con las migraciones otoñales, todos los individuos de P. haliaetus macho y todos los individuos de la costa este emplearon menos días migrando, menos días en periodos de descanso a lo largo de la ruta de migración, viajaron distancias más cortas en general y viajaron más lejos (en promedio) cada día durante la primavera. En contraste, las características migratorias de otoño y primavera de todos los individuos hembra y macho de P. haliaetus fueron similares. Estos hallazgos sugieren que aunque el sexo y la ubicación del sitio de reproducción pueden influir en la estrategia de migración primaveral utilizada por los individuos de P. haliaetus, tanto hembras como machos minimizan el tiempo empleado en la migración para asegurarse un arribo a tiempo a los sitios de reproducción para establecer o defender un territorio de nidada.

Satellite Tracking of Bald Eagles in the Upper Midwest

Abstract We investigated the movement ecology of Bald Eagles (Haliaeetus leucocephalus) that winter along the Upper Mississippi River Valley. During late autumn and winter from March 1999 through February 2006, we outfitted with satellite transmitters 14 wild-caught Bald Eagles (12 adults, 2 subadults) on a winter range or migration stopover point in southwestern Wisconsin. These birds wintered as far south as the Mississippi and Illinois rivers, northwest of St. Louis, Missouri. Summer ranges extended out from the Upper Mississippi River Valley migration corridor as far north as Arviat, Nunavut, Canada, on the western shore of Hudson Bay. Migration route fidelity was apparent, with two notable exceptions. Fidelity to summer and winter ranges also was apparent, but variable. Some eagles remained on a small range the entire season; others traveled extensively, often to the same areas in successive years. Spring migration mean start and end dates for adults were 24 February ± 23 (SD) d and 27 April ± 40 d, respectively. Eagles took from 6–151 d to reach their summer ranges (mean: 67 ± 48 d). Mean start and end dates for autumn migration were 21 October ± 28 d and 11 December ± 16 d, respectively; travel duration ranged from 15–77 d (mean: 51 ± 20 d). Individual mean straight-line distances between core winter and summer ranges ranged from 611–2222 km (mean: 1655 ± 526 km). Our study provided new information on Bald Eagle movement ecology in a vast region where such knowledge was previously lacking. Compared to other tracking studies of Bald Eagles, our study documented greater variation in migration timing and duration, but similar range and route fidelity and distances traveled. RASTREO SATELITAL DE HALIAEETUS LEUCOCEPHALUS EN EL MEDIO OESTE SUPERIOR Investigamos la ecología de movimiento de individuos de Haliaeetus leucocephalus que invernan a lo largo del Valle Superior del Río Mississippi. Durante el otoño tardío y el invierno de marzo de 1999 hasta febrero de 2006, equipamos con transmisores satelitales a 14 individuos silvestres de H. leucocephalus atrapados (12 adultos, 2 subadultos) en un área de invernada o en puntos de parada de migración en el sudoeste de Wisconsin. Estas aves invernaron hacia el sur hasta los ríos Mississippi e Illinois, al noroeste de St. Louis, Missouri. La distribución durante el verano se extendió desde el corredor migratorio del Valle Superior del Río Mississippi hacia el norte hasta Arviat, Nunavut, Canadá, en la costa oeste de la Bahía de Hudson. La fidelidad a la ruta de migración fue evidente, con dos excepciones notables. La fidelidad a las distribuciones de verano e invierno también fue evidente, pero variable. Algunas águilas permanecieron en un área pequeña durante toda la estación; otras viajaron considerablemente, a menudo a las mismas áreas en años consecutivos. Las fechas medias de comienzo y finalización de la migración de primavera fueron 24 de febrero ± 23 (DE) días y 27 de abril ± 40 días, respectivamente. A las águilas les tomó 6–151 días llegar a sus áreas de verano (media: 67 ± 48 días). Las fechas medias para el comienzo y finalización de la migración de otoño fueron 21 de octubre ± 28 días y 11 de diciembre ± 16 días, respectivamente. La duración del viaje varió entre 15–77 días (media: 51 ± 20 días). Las distancias medias en línea recta individuales entre las áreas núcleo de invierno y verano oscilaron entre 611–2222 km (media: 1655 ± 526 km). Nuestro estudio brindó nueva información acerca de la ecología de movimiento de H. leucocephalus en una vasta región para la que faltaba este conocimiento. Comparado con otros estudios de rastreo de H. leucochephalus, el nuestro documentó una mayor variación en el tiempo y duración de la migración, pero una similitud con respecto a áreas, fidelidad de rutas y distancias recorridas.

Wintering Ecology of Adult North American Ospreys

Abstract North American Ospreys (Pandion haliaetus) typically migrate long distances to their wintering grounds in the tropics. Beyond the general distribution of their wintering range (i.e., the Caribbean, South America, and Central America), very little is known about the wintering ecology of these birds. We used satellite telemetry to determine the duration of wintering period, to examine the characteristics of wintering areas used by Ospreys, and to quantify space use and activity patterns of wintering Ospreys. Adult Ospreys migrated to wintering sites and exhibited high wintering site fidelity among years. Overall, Ospreys wintered on river systems (50.6%) more than on lakes (19.0%), and use of coastal areas was (30.4%) intermediate. Ospreys remained on their wintering grounds for an average of 154 d for males and 167 d for females. Locations of wintering Ospreys obtained via GPS-capable satellite telemetry suggest these birds move infrequently and their movements are very localized (i.e., <5 km from selected roosting areas). Sizes of home ranges and core-use areas for wintering Ospreys averaged 12.7 km2 and 1.4 km2, respectively. Overall, our findings suggest wintering adult North American Ospreys are very sedentary, demonstrating a pattern of limited daily movements and high fidelity to a few select locations (presumably roosts). We suggest this wintering strategy might be effective for reducing the risk of mortality and maximizing energy conservation. Ecología de Invernada de Individuos Adultos de Pandion haliaetus Pandion haliaetus típicamente migra grandes distancias hacia sus sitios de invernada en los trópicos. Más allá de la distribución general del rango de invernada (i.e., el Caribe, América del Sur y América Central), se sabe muy poco sobre la ecología de invernada de esta especie. Utilizamos telemetría satelital para determinar la duración del periodo de invernada, examinar las características de las áreas de invernada utilizadas por P. haliaetus y cuantificar el uso del espacio y los patrones de actividad de individuos de esta especie. Los individuos adultos de P. haliaetus migraron hacia los sitios de invernada y exhibieron una elevada fidelidad por el sitio de invernada entre años. En general, P. haliaetus invernó en sistemas riparios (50.6%) más que en lagos (19.0%) y el uso de zonas costeras fue (30.4%) intermedio. Los individuos de P. haliaetus permanecieron en sus áreas de invernada un promedio de 154 días para los machos y 167 días para las hembras. Las ubicaciones de individuos de P. haliaetus obtenidas vía telemetría satelital GPS sugieren que estas aves se mueven con poca frecuencia y que sus movimientos son muy localizados (i.e., <5 km de las áreas de dormideros seleccionadas). El tamaño de las áreas de hogar y áreas núcleo de uso para invernada en P. haliaetus promedió 12.7 km2 y 1.4 km2 respectivamente. En general, estos hallazgos sugieren que los individuos adultos de P. haliaetus invernantes son muy sedentarios, demostrando un patrón de movimientos diarios limitado y una elevada fidelidad a las ubicaciones seleccionadas (presumiblemente dormideros). Sugerimos que esta estrategia de invernada puede ser efectiva para reducir el riesgo de mortalidad y maximizar la conservación de energía.

Satellite-tagged Osprey Nearly Sets Longevity Record and Productivity Response to Initial Captures

We equipped adult Ospreys (Pandion haliaetus) from 24 nests in Oregon/Washington with satellite-tracked batterypowered radios, known as platform transmitter terminals (PTTs), in 1996–1999. These Ospreys from the lower Columbia River (river miles 76–286), and the Willamette Valley in western Oregon were part of a larger study of Osprey fall migration, wintering ecology, and spring migration, which included additional adults from the Upper Midwest and East Coast of the United States (Martell et al. 2001, 2014, Washburn et al. 2014). These earlygeneration PTTs weighed 30–35 g (Microwave Telemetry Inc., Columbia, MD U.S.A.) and utilized the ARGOS tracking system (www.argos-system.org). We placed PTTs on the birds’ backs using Teflon ribbon (Bally Ribbon, Bally, PA U.S.A.) in a standard backpack configuration (Kenward 2001). With the mass of adult male Ospreys 1400 to 1500 g (Poole et al. 2002), the ratio of tag mass to body mass was 2.0 to 2.5%. Ospreys also received a standard size 8 bird band (U.S. Geological Survey) on one leg and a numbered color band on the other. For more details on trapping techniques, attachment procedures, the batterypowered units, turn-on, turn-off cycles, and tracking equipment, see Martell et al. (2001). The longevity record of one adult male captured at its nest on 4 June 1996 warrants special attention. We equipped this Osprey with a PTT, a metal color band (alphanumeric code X3) and band 608-43025. This male (hereafter ‘‘X3’’) nested on the Washington side of the Columbia River near Bachelor Point on Channel Marker 13 at River Mile 91 (Fig. 1), Nest #91 in our records. Female X2 (hereafter ‘‘X2’’), mate of X3, was also captured and equipped with a PTT in 1996, but provided limited longevity information. The PTT from the X3 sent signals for almost a year (6 June 1996 to 17 April 1997). After the 1996 breeding season, he was last detected at the nesting area 16 September 1996, and 10 d later (26 September) had migrated to his wintering area east of Los Mochis in northcentral Sinaloa, Mexico (25850.88N, 107850.52W), at Bacurato Reservoir (a straight-line distance of 2583 km, suggesting an average migration rate of 258 km/d). The duty cycle setting on the PTT prevented us from receiving any information during his movements between the nesting and wintering area. After nearly 6 mo in Mexico, X3 was last detected at his wintering area 24 March 1997, and arrived back at the nesting area between 1–7 April. His spring migration took him through Sonora, Mexico (28 March), at 28856.46N, 11284.74W and just east of San Francisco, CA (31 March) at 3883.54N, 120837.86W. His mate X2 wintered along the coast approximately 120 km south-southeast of Mazatlan in the state of Nayarit, Mexico, at 22822.32N, 105838.04W (ca. 450 km away); she was last detected there on 18 March 1997 and arrived back at the nesting area between 28–31 March. We did not visit the nest on a regular basis, but did observe both Ospreys together back at Nest #91 on 14 April 1997. The final PTT transmission from X3 was from the nesting area on 17 April 1997. With no information for 1998 or 1999, our next field observation was on 20 June 2000, when X2 and X3 were again at Nest #91 with three young about 7–10 d old. A volunteer at nearby Ridgefield National Wildlife Refuge then photographed X3 (Fig. 2, note transmitter on back) at the refuge, 3.32 km from Nest #91 on 7 June 2011. Unfortunately, X3 was electrocuted at a distribution utility pole 3.98 km from its 1996 nest site on 27 April 2016 (38 d short of 20 yr after we attached the PTT) still carrying the PTT. Because the male was an adult when captured (at least 3 yr old, see Poole et al. 2002), this male Osprey was at least 22.83 yr old (years and months converted to decimal at Bird Banding Laboratory [BBL]) at the time of its death. And, 1 Email address: hennyc@usgs.gov

BROOD SIZE AND SURVIVAL TO BREEDING IN MIDWESTERN PEREGRINE FALCONS

Abstract Because brood size might affect nutrition or behavioral development of young Peregrine Falcons (Falco peregrinus), we explored the relationship of the size of the brood from which individuals fledged to their probability of surviving to become breeders in the midwestern United States. In our sample, the probability of an individual peregrine surviving to become a breeder was not related to size of the brood from which it fledged, based on 139 broods fledging 379 young of which at least 38 survived to become breeders.