21 research outputs found
Migrating Birds and Tickborne Encephalitis Virus
During spring and autumn 2001, we screened 13,260 migrating birds at Ottenby Bird Observatory, Sweden, and found 3.4% were infested with ticks. Four birds, each a different passerine species, carried tickborne encephalitis virus (TBEV)âinfected ticks (Ixodes ricinus). Migrating birds may play a role in the geographic dispersal of TBEV-infected ticks
Surveillance of Influenza Virus A in Migratory Waterfowl in Northern Europe
Ducks may maintain influenza virus from 1 year to the next
The relationship between canopy cover and colony size of the wood ant Formica lugubris : implications for the thermal effects on a keystone ant species
Climate change may affect ecosystems and biodiversity through the impacts of rising temperature on species' body size. In terms of physiology and genetics, the colony is the unit of selection for ants so colony size can be considered the body size of a colony. For polydomous ant species, a colony is spread across several nests. This study aims to clarify how climate change may influence an ecologically significant ant species group by investigating thermal effects on wood ant colony size. The strong link between canopy cover and the local temperatures of wood ant's nesting location provides a feasible approach for our study. Our results showed that nests were larger in shadier areas where the thermal environment was colder and more stable compared to open areas. Colonies (sum of nests in a polydomous colony) also tended to be larger in shadier areas than in open areas. In addition to temperature, our results supported that food resource availability may be an additional factor mediating the relationship between canopy cover and nest size. The effects of canopy cover on total colony size may act at the nest level because of the positive relationship between total colony size and mean nest size, rather than at the colony level due to lack of link between canopy cover and number of nests per colony. Causal relationships between the environment and the life-history characteristics may suggest possible future impacts of climate change on these species
A comparison of contributions from the Aztec cities of Tlatelolco and Tenochtitlan to the bird chapter of the Florentine Codex
The Florentine Codex is a Renaissance-era illuminated manuscript that contains the earliest-known regional work on the birds of MĂ©xico. Its Nahuatl language texts and scholia (the latter later incorporated into its Spanish texts) were written in the 1560s by Bernardino de SahagĂșnâs research group of elite native Mexican scholars in collaboration with Aztecs from two cities: Tlatelolco and Tenochtitlan. In the present study, I compared the contributions from these two cities and found many differences. While both cities contributed accounts and descriptions of land and water birds, those from Tlatelolco were mainly land birds, while those from Tenochtitlan were mainly water birds. Tlatelolco contributed over twice as many bird accounts as Tenochtitlan, and supplied the only information about medicinal uses of birds. Tenochtitlan peer reviewed the Tlatelolco bird accounts and improved many of them. In addition, Tenochtitlan contributed all information on bird abundance and most information about which birds were eaten and not eaten by humans. Spanish bird names appear more frequently in the Aztec language texts from Tenochtitlan. Content analysis of the Tenochtitlan accounts suggests collaboration with the water folk Atlaca (a prehistoric lacustrine culture) and indigenous contacts with Spanish falconers. The Renaissance-era studies of SahagĂșnâs research group, on a now lost island in the formerly vast, bird-rich wetlands of the Valley of MĂ©xico, constitute the birth of Mexican ornithology and, coincidently, give the history of Mexican ornithology a distinctive, AztlĂĄn-like beginning, significantly different from the ornithological histories of neighboring countries
Ecology and phylogeny of birds foraging at outdoor restaurants in Sweden
Background: Birds frequently visit the outdoor serving areas of restaurants to feed on scraps of food and leftovers. Although this feeding association between humans and birds is widespread and could have significant effects, both positive and negative, for all taxa involved, the authors know of no published studies that have investigated restaurant bird communities. To lay the foundation for future research, the authors conducted a basic study of birds at 80 outdoor restaurants in Sweden, identifying which species and taxonomic clades of birds visited the restaurants and comparing restaurant birds in urban and rural environments. New information: Thirteen species of birds visited the outdoor restaurants. Eight of these species were predominant, i.e. accounting for 51% or more of bird presence (sum of minutes of all individual birds) at one or more restaurants. Every restaurant studied had a predominant species, but species often differed from each other in frequency of predominance in different landscapes. No endangered species were seen visiting restaurants. However, three farmland bird species (House Sparrow Passer domesticus, White Wagtail Motacilla alba, Eurasian Tree Sparrow Passer montanus), whose numbers are reported to be declining in the countryside, were predominant at the majority of restaurants in rural areas, suggesting that rural restaurants might be able to contribute to the conservation of these species. The thirteen species of restaurant-visiting birds belonged to five monophyletic clades. Ninety percent of all restaurants had, as their predominant species, birds from either Clade A (Passeridae, Motacillidae, Fringillidae) or Clade C (Corvidae). Statistical testing revealed that Clade A and Clade C were distributed differently in environments along the urban-rural gradient. At all spatial scales measured, birds of Clade C were predominant at the majority of restaurants in urban areas, while birds of Clade A were the predominant clade at the majority of restaurants in rural areas. The authors use this evidence, and observations of birds foraging in association with other primates, to hypothesize that the outdoor serving areas of modern restaurants may be helping to preserve and nurture ancient human-bird symbioses that have been part of human ecology since antiquity