Recent photo-identification and genetic studies have identified at least five discrete breeding populations in Australia and Oceania: western Australia (D), eastern Australia (E (i)), New Caledonia (E (ii)), Tonga (E (iii)), French... more
Recent photo-identification and genetic studies have identified at least five discrete breeding populations in Australia and Oceania: western Australia (D), eastern Australia (E (i)), New Caledonia (E (ii)), Tonga (E (iii)), French Polynesia and the Cook Islands (F). Also evident are low levels of intermingling among breeding populations consistent with the degree of genetic differentiation. Photo-identification has confirmed linkages between Area V feeding areas and eastern Australia breeding grounds and one genotype match has been reported between Area V feeding areas and Oceania breeding grounds. Recent abundance estimates show strong increases in the eastern Australian population, and some recovery in the New Caledonia and Tonga populations, but with little evidence of recovery at other known Oceania breeding grounds or New Zealand. Studies to date have provided no conclusive evidence of the migratory destination of humpback whales passing through New Zealand waters en route between Antarctic feeding areas and tropical breeding grounds. Photo-identification comparisons were undertaken between humpback whale fluke catalogues from eastern Australia (EA, 1315), Oceania east (OE, 513), Oceania west (OW, 166) and New Zealand (NZ, 13). Five matches were found between OE/OW, four matches between OW/EA and three matches between NZ/EA. The data are used to investigate and discuss the migratory destination and breeding ground migratory interchange of humpback whales travelling through New Zealand waters. The data confirm that humpback whales with site fidelity to eastern Australia migrate past New Zealand including through the Cook Strait and Foveaux Strait.
The annual migration of monarch butterflies (Danaus plexippus) has high cultural value and recent surveys indicate monarch populations are declining. Protecting migratory species such as monarchs is complex because they cross... more
The annual migration of monarch butterflies (Danaus plexippus) has high cultural value and recent surveys indicate monarch populations are declining. Protecting migratory species such as monarchs is complex because they cross international borders and depend on multiple regions during their annual cycle. Understanding how much, and where, humans place value on migratory species can facilitate incentive-based conservation programs. We performed a valuation study of monarchs to understand the potential for incentive-based conservation. The survey asked U.S. respondents about the money they would spend, or have spent, growing monarch-friendly plants, and the amount they would donate to monarch conservation organizations. Combining planting payments and donations to organizations, the survey indicated U.S. households would make a total one-time payment of $4.78 to $6.64 billion in support of monarch conservation, levels similar to many endangered vertebrate species. These high values indicate a large, untapped potential for market-based monarch habitat conservation.
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... more
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 (δDgw; precipitation proxy), sex, amount of precipitation, and the coefficient of variation in amount of precipitation. Overall, δDgw was a poor predictor of sparrow δDf 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 δDgw and δDf was found for female sparrows in the Atlantic drainage basin (r2=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.
Many migratory animals are experiencing rapid population declines, but migration data with the geographic scope and resolution to quantify the complex network of movements between breeding and nonbreeding regions are often lacking.... more
Many migratory animals are experiencing rapid population declines, but migration data with the geographic scope and resolution to quantify the complex network of movements between breeding and nonbreeding regions are often lacking. Determining the most frequently used migration routes and nonbreeding regions for a species is critical for understanding population dynamics and making effective conservation decisions. We tracked the migration of individual Wood Thrushes (Hylocichla mustelina) (n = 102) from across their range with light-level geolocators and, for the first time, quantified migration routes and wintering regions for distinct breeding populations. We identified regional and species-level migratory connectivity networks for this declining songbird by combining our tracking results with range-wide breeding abundance estimates and forest cover data. More than 50% of the species occupied the eastern wintering range (Honduras to Costa Rica), a region that includes only one-third of all wintering habitat and that is undergoing intensive deforestation. We estimated that half of all Wood Thrushes in North America migrate south through Florida in fall, whereas in spring approximately 73% funnel northward through a narrow span along the central U.S. Gulf Coast (88–93°W). Identifying migratory networks is a critical step for conservation of songbirds and we demonstrated with Wood Thrushes how it can highlight conservation hotspots for regional populations and species as a whole. Resumen: Muchos animales migratorios están experimentando declinaciones poblacionales rápidas, pero la información migratoria con el enfoque geográfico y la resolución para cuantificar la red completa de movimientos entre regiones reproductivas y no reproductivas con frecuencia es carente. Determinar las rutas y las regiones no-reproductivas usadas con mayor frecuencia por una especie es crítico para entender las dinámicas poblacionales y hacer decisiones de conservación efectivas. Rastreamos la migración individual de zorzales (Hylocichla mustelina) (n = 102) a lo largo de su extensión con geolocalizadores de bajo nivel y, por primera vez, cuantificamos la conectividad de las rutas migratorias y las regiones de invierno para poblaciones reproductivas diferentes. Identificamos redes de conectividad migratoria regionales y a nivel de especie para esta ave canora en declive al combinar nuestros resultados de rastreo con los estimados de abundancia reproductiva de cobertura amplia y los datos de cubierta forestal. Más del 50% de las especies ocuparon la cobertura occidental de invierno (de Honduras a Costa Rica), una región que incluye sólo un tercio de todo el hábitat de invierno y que está sometida a una deforestación intensiva. Estimamos que la mitad de los zorzales en América del Norte migran al sur por Florida en el otoño, mientras que en la primavera
