Ornithology

The brolga Grus rubicunda breeds primarily in shallow freshwater wetlands and is classified as Vulnerable in Victoria. Specific guidelines have been developed to mitigate potential impacts of the wind industry on brolga populations. Identifying brolga nest sites is a key aspect of these guidelines and aerial surveys are suggested as one method. We used aerial surveys to identify brolga nesting sites over a large area of south-western Victoria during the 2009 and 2010 breeding seasons. We surveyed approximately 800 km2 over the two seasons, and detected 44 nests which were subsequently ground-truthed. Of these nests, nine were confirmed as belonging to brolgas, 14 as belonging to black swan Cygnus atratus and 21 were either abandoned or not accessible. Aerial surveys covered a much larger survey area over a shorter time period compared with ground surveys (approximately half the time), and covered wetlands not otherwise easily accessible (e.g. sites located away from roads and/or on private property). Given the difficulties in distinguishing between brolga and black swan nests, it is imperative that wetlands are ground truthed to accurately identify nests. Given that not all nests are active concurrently in a given season, our results reveal that at least two aerial surveys are required across a study area to detect 75 % of the brolga nests in a season.

We used information from eBird, the U.S. Geological Survey's Breeding Bird Survey, Christmas Bird Counts, and agency studies and records to evaluate the historical and recent breeding and wintering status of the Osprey (Pandion halieatus) in the Central Valley and surrounding foothills of California. Although early information is scarce, Ospreys likely occupied water bodies prior to European colonization but were mostly eliminated by human persecution. Re-colonization of the Central Valley by breeders began mainly in the northern portion of the Valley in the mid-1970s, presumably in response to recovery of adjacent populations following the banning of DDT (dichlorodiphenyltrichloroethane) in 1972. Breeding and wintering birds appear to have colonized most available habitat in the 1980s and early 1990s and increased in abundance and density over the subsequent decade. Assessment of recent trends among breeders is complicated by substantial increases in reporting effort in eBird, but available data demonstrate that the species is established throughout the Valley in suitable aquatic habitat. The data suggest that the wintering population has stabilized, and perhaps declined slightly, in the northern Central Valley over the last decade. Recent colonization and population increase likely has resulted from a healthier source population, increased reservoir habitat, reduced persecution, and adoption of anthropogenic structures for nesting. The Osprey breeding population may decline or experience reduced productivity as more frequent and severe drought conditions anticipated under climate change reduce aquatic foraging habitat and fish prey. ______________________________________________________________ The historical and recent status of the Osprey (Pandion halieatus) in the Central Valley has not been well documented. Although general knowledge and unpublished data suggests a substantial recent range expansion within the Central Valley, better information is needed to describe the history and current status of the population.

We used archived recordings of Ruby-crowned Kinglet (Corthylio calendula) songs to examine characteristics of the song, repertoire size, and regional dialects across the species' breeding range and to assess possible cultural evolution in dialects. Using recordings of 313 individuals, we confirmed that individuals have a single song type and that there are distinct regional song dialects. Our examination of phrases that form the last of this species' 3-part song revealed 43 different phrase types. We defined seven regions based on geographic features, ecoregions, and obvious clustering of particular phrase types. An eighth region corresponded to the published range of the subspecies C. c. grinnellii, coastal southern Alaska and the British Columbia coast. In each of those regions, two to three phrase types dominated and were found exclusively or primarily within a single region. Our finding of regional dialects confirms that the song of the Ruby-crowned Kinglet is, at least with respect to this phrase, learned rather than innate. In species, such as this kinglet that sing during migration or in their non-breeding range, mapped dialects can help reveal migration strategy and migratory connectivity. Monitoring changes in dialects over time can confirm cultural evolution and shed light on both the timing and location of song learning. RESUMEN. Utilizamos grabaciones en repositorios de cantos del Reyezuelo Rubí (Corthylio calendula) para examinar las características del canto, el tamaño del repertorio y los dialectos regionales a lo largo del área de reproducción de la especie y para evaluar la posible evolución cultural de los dialectos. Utilizando grabaciones de 313 individuos, confirmamos que los individuos tienen un único tipo de canto y que existen distintos dialectos regionales de canto. Nuestro examinación de las frases que forman la última parte del canto de esta especie que está dividido en tres partes reveló 43 tipos de frases diferentes. Definimos siete regiones basadas en características geográficas, ecorregiones y agrupaciones evidentes de tipos de frases particulares. Una octava región correspondía al área de distribución publicada de la subespecie C. c. grinnellii, el sur de Alaska y la costa de la British Columbia. En cada una de estas regiones, dominaban de dos a tres tipos de frases y se encontraban exclusiva o principalmente en una sola región. Nuestro hallazgo de los dialectos regionales confirma que el canto del C. calendula es, al menos con respecto a esta frase, aprendido más que innato. En especies, como este reyezuelo, que cantan durante la migración o en su área de distribución no reproductiva, los dialectos mapeados pueden ayudar a revelar la estrategia de migración y la conectividad migratoria. El seguimiento de los cambios en los dialectos a lo largo del tiempo puede confirmar la evolución cultural y arrojar luz sobre el momento y la ubicación del aprendizaje del canto.