We used a double-sampling technique (air plus ground survey) in 2006, with partial double coverage, to estimate the present size of the Osprey (Pandion haliaetus) nesting population in northwestern Mexico (coastal Baja California, islands in the Gulf of California, and coastal Sonora and Sinaloa). With the exception of Natividad, Cedros, and San Benitos islands along the Pacific coast of Baja California (all three excluded from our coverage in 2006 due to fog), this survey was a repeat of previous surveys conducted by us with the same protocol in 1977 and 1992/1993, allowing for estimates of regional population trends. The minimum population estimate for the area we surveyed in 2006 was 1343 nesting pairs, an 81% increase since 1977, but only a 3% increase since 1992/1993. The population on the Gulf side of Baja California generally remained stable during the three surveys (255, 236, and 252 pairs, respectively). The population of the Midriff Islands (Gulf of California in the vicinity of 29°N latitude) remained similar from 1992/1993 (308 pairs) to 2006 (289 pairs), but with notable population changes on the largest two islands (Guardian Angel: 45 to 105 pairs [133% increase]; Tiburón: 164 to 109 pairs [34% decrease]). The minimum estimated Osprey population on the Sonora mainland decreased in a manner similar to adjacent Isla Tiburón, i.e., by 26%, from 214 pairs in 1993 to 158 pairs in 2006. In contrast, the population in coastal Sinaloa, which had increased by 150% between 1977 and 1993, grew again by 58% between 1993 and 2006, from 180 to 285 pairs. Our survey confirmed previously described patterns of rapid population changes at a local level, coupled with apparent shifts in spatial distribution. The large ground-nesting population that until recently nested on two islands in San Ignacio Lagoon ( Pacific Ocean side, Baja California) was no longer present on the islands in 2006, but an equivalent number of pairs were found to the north and south of the lagoon, nesting in small towns and along adjoining overhead electric lines, with no overall change in population size for that general area (198 pairs in 1992; 199 in 2006). Use of artificial nesting structures was 4.3% in 1977 and 6.2% in 1992/1993, but jumped to 26.4% in 2006. Use of poles that support overhead electric lines poses a risk of electrocution to Ospreys and also causes power outages and fires. We recommend modification of these poles to safely accommodate Osprey nests, as has been successfully accomplished in many countries.

Thirty-eight eye injuries and abnormalities were noted over a 22-yr period studying Long-eared Owls (Asio otus). Injury frequency, distribution per eye, shape, size, and directionality, are reported. The prevalence rate was low (2.05%), as only 31 of 1510 owls had noticeable injuries to the iris. Seven other noticeable eye abnormalities are also described. There was no significant difference between the number of injuries in the left versus right eye; however, there were significantly more injuries in the bottom half of the eye verses the top, suggesting some directionality. Nine of the owls with iris injuries were recaptured between 2 wk and 3 yr later, with four of the nine recaptured 1–3 yr later. Two owls with noticeable eye abnormalities were recaptured 2 mo and 4 mo later. This suggests the ability of some individuals to survive with ocular trauma.

A variety of factors influence prey selection by predators. Because Barn Owls (Tyto alba) and Burrowing Owls (Athene cunicularia) differ in size and foraging tactics, we expected differential predation on small mammal prey. We hypothesized that the Barn Owl, an active predator, would prey on smaller and younger individuals than the Burrowing Owl, a sit-and-wait predator. We used pellet analyses to evaluate selection of small mammals by the two owls in relation to prey species, age, and size at the Ecological Station of Itirapina, state of São Paulo, in southeastern Brazil. Small mammals constituted most of the prey individuals and biomass in the diet of Barn Owls. Although Burrowing Owls consumed a wider range of taxa, small mammals represented one-third of all biomass consumed. With respect to small mammals, Barn Owls foraged selectively relative to prey species, size, and age. Burrowing Owls foraged opportunistically relative to prey species, but selectively relative to prey size and age. Barn Owls selected smaller and younger (juvenile and subadult) individuals of the delicate vesper mouse (Calomys tener) and Burrowing Owls preyed more on larger and older (subadult only) individuals. Morphology and behavior of both prey and predators may explain this differential predation. Our data suggest that the active predator feeds on smaller and younger prey and the sit-and-wait predator took relatively larger and older prey.

We studied the diet of the endemic New Zealand Falcon (Falco novaeseelandiae) in a pine plantation forest by identifying species occurring in pellets and prey remains collected from 37 nest sites during the 2003 and 2004 breeding seasons. We assessed bird species abundance along transects in different-aged pine stands and along stand edges. Diet and prey abundance were compared to determine whether birds were taken disproportionately or in proportion to their abundance in the environment. Birds composed the greatest proportion of the diet, 84% by frequency and 74% by biomass. Common Chaffinches (Fringilla coelebs) were taken most frequently, but Eurasian Blackbirds (Turdus merula) and European rabbits (Oryctolagus cuniculus) contributed more by biomass, although rabbits were not recorded at every nest site. Bird density increased significantly with stand age but was highest along stand edges. Chaffinches were the most abundant species and taken in proportion to their availability. Species that occurred in open habitat (e.g., Yellowhammers [Emberiza citrinella]) or were of medium size (e.g., blackbirds) were taken more than expected based on their availability. Very small species (e.g., Grey Gerygone [Gerygone igata]) were taken in lower proportions than expected from their abundance. Proportions of bird species preyed upon were correlated most closely with bird species abundance in young pine stands (P  =  0.02, r²  =  0.52). In a pine plantation habitat, New Zealand Falcons took primarily the more abundant species, those intermediate in size (16–160 g), and those frequenting open habitat.

A new species of caracara, Caracara tellustris, is described from cave deposits in the arid Portland Ridge area of southern Jamaica. It is characterized by great size and much reduced wings, and was probably almost completely terrestrial in habits if not even flightless. It was thus probably confined to the more arid southern areas of the island where open country would be compatible with a terrestrial mode of life.

The eastern Junggar Basin in northwest China is a potential area of sympatry for breeding Long-legged Buzzards (Buteo rufinus) and Upland Buzzards (B. hemilasius). However, during a breeding season survey in 2005, the Long-legged Buzzard was the only species recorded present in this semidesert region. The minimum breeding density within our survey area was 0.19 breeding pairs/100 km² and all nests were located either on rock faces or clay cliffs. There was little overlap in the location of Long-legged Buzzard and Golden Eagle nest sites, possibly as a result of interspecific competition. We present here information on clutch size (mean  =  3.3 eggs), brood development, and fledging success (0.7 chicks per breeding pair), as well as on the diet during the breeding season. Mammalian prey, especially the great gerbil (Rhombomys opimus), made up most of the diet of Long-legged Buzzards.

We describe species of lice collected from 12 species of Chilean diurnal raptors. Sampled raptors were obtained from wildlife rehabilitation centers and zoos, as carcasses found along highways, and from the avian collection of the National Museum of Natural History. Fourteen species of lice were isolated from all raptor hosts, with genus Degeeriella Neumann, 1906 (Philopteridae) and Colpocephalum Nitzsch, 1818 (Menoponidae) the most frequently found (60% and 26% of all lice, respectively). Degeeriella leucopleura (Nitzsch in Giebel, 1874) from Cinereous Harrier (Circus cinereus), D. carruthi Emerson, 1953 from American Kestrel (Falco sparverius) and Colpocephalum maculatum Piaget, 1880 from Southern Caracara (Caracara plancus) were the lice most commonly collected. Including data from previous studies, we found that in Chilean Falconiformes (1) Colpocephalum turbinatum Denny, 1842 is the louse species associated with the greatest number of raptor species, (2) Degeeriella fulva and Laemobothrion tinnunculi are characteristic of the genera of Buteo and Falco, respectively, and (3) the degree of host-specificity is high (76% of all louse species were associated with only one species host). Thus, our results are similar to those observed for other raptor hosts worldwide.

Entre mayo y noviembre de 2005, realicé búsquedas de Spizaetus ornatus y S. tyrannus en el Parque Nacional Soberanía (221 km²), centro de Panamá. Los censos fueron realizados durante 574 horas en un total de 87 días (promedio 5.2 hr/d), a lo largo de transectos aleatorios ubicados en bosque húmedo tropical estructuralmente maduro y bosque humedo tropical de crecimiento secundario, incluyendo bordes de bosque, quebradas y ríos, colinas, fincas ubicadas alrededor de la reserva, poblaciones pequeñas, una línea férrea y un lago (Lago Gatún, Canal de Panamá). Realicé 13 y 17 observaciones de parejas o individuos de S. ornatus y S. tyrannus, respectivamente, y ubiqué la posición geográfica de cada registro en un mapa digital. También registré los comportamientos reproductivos observados durante cada encuentro. De las 17 observaciones de S. tyrannus, el 58% fueron dentro de hábitats boscosos y el 42% en bordes de bosque. Las 13 observaciones de S. ornatus fueron en interior de bosques, lo que sugiere que esta especie es más sensible a la fragmentación del hábitat o a la deforestación en comparación con S. tyrannus. Con base en el tamaño del área censada, el número de parejas observadas, el comportamiento reproductivo y la distncia entre registros, estimé que existen al menos 4.9 parejas (1 pareja/44.4 km²) de S. ornatus y 7.4 parejas (1 pareja/29.6 km² en promedio) de S. tyrannus en el Parque Nacional Soberanía.

La dieta de Asio otus es bien conocida en Europa debido a que esta especie tiende a congregarse en el invierno, y los investigadores pueden obtener cientos de egagrópilas de estas agrupaciones de individuos. La dieta invernal de la especie fue estudiada en Tulcea, delta del Danubio, Rumania. La dieta de la población invernante incluyó predominantemente aves (59.3%), con una alta diversidad de especies de presas, lo que es atípico para A. otus. La explicación más probable de esta dieta inusual es que el ambiente que rodea a Tulcea se caracteriza por la presencia de amplias extensiones de humedales con cobertura de agua ocasional, ambientes que no son adecuados para la invernación de pequeños mamíferos pero que son excelentes para paserinos pequeños.

Identificamos los pichones de dos especies de aves canoras que anidan en el suelo, Catharus guttatus y Seiurus aurocapilla, como presas de Strix varia en el norte de Minnesota. Mediante el uso de radio telemetría, encontramos transmisores y anillos de tres pichones de C. guttatus y tres de S. aurocapilla en tres egagrópilas de S. varia. Aunque se sabe que las aves constituyen una pequeña fracción de la dieta de primavera y verano de S. varia, hay pocos registros publicados que documentan cuales especies de aves canoras son consumidas. Nuestras observaciones confirmaron que los pichones recién salidos del nido de aves canoras que anidan en el suelo contribuyen a la dieta de S. varia durante la primavera y el verano.