The potential for comparative research across New World bird migration systems

For a migratory bird, the costs and benefits of utilizing a given migratory strategy vary according to the biotic (e. g., physiology) and abiotic (e. g., weather) constraints it experiences throughout the year. In the New World, closely related species migrate to breeding grounds located across a wide range of latitudes, from northern North America to southern South America. Because the ultimate goal of a bird on spring migration is to successfully arrive on the breeding grounds in a timely manner, events that occur during the breeding season (e. g., amount of time available to breed) could affect, through selection pressures, the behavior of birds on spring migration. Variation across north temperate, tropical, and south temperate latitudes in breeding strategies, breeding season length, and availability of food during the breeding season has been well documented in various bird species. Thus, such factors as migratory strategies, risk of mortality on migration, and effects of climate change on migratory patterns may also vary predictably, depending on the latitude, both north and south of the Equator, at which a migratory population breeds. Comparing such patterns across the New World, using interdisciplinary approaches and the latest in technological advances, holds promise for better understanding how migratory birds accomplish these spectacular journeys.Fil: Jahn, Alex. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Cueto, Víctor. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

“Good” and “Bad” Urban Wildlife

Urban environments offer habitat for many species of animals. Although some of those are ubiquitous and/or undesirable, others are native and in some cases, of conservation value. In many cases, urban wildlife populations are a source of enjoyment for human residents, who sometimes invest considerable amounts in attracting them to yards and public spaces. Their presence there can serve an important educational role that helps protect non-urban habitats and species. Nonetheless, urban wildlife must survive what has been termed a landscape of fear. Although some of the urban wildlife that do well in this environment are benign, other populations - sometimes of a species that, in other locations, is iconic and desirable - can become problematic. Some species can serve as vectors that carry important zoonosis, such as the plague or diseases that affect other wildlife. Others can create noise or olfactory nuisances and degrade structures or usability of public spaces. Some pose hazards at busy airports, whereas still others may present an envenomation or predation risk on unwary humans. Here, we review the role that reptiles, birds, and mammals play in urban environments and discuss how urban wildlife rehabilitation centers help address some related issues. We close by looking ahead and trying to predict how global patterns such as increased urbanization and population growth may affect urban wildlife and its value for conservation