Search results for "Bird"
showing 10 items of 420 documents
Patterns of morphological variation in two sexually dimorphic bird species with different tail shapes
2007
Many studies have focused on tail ornamentation in birds, but not all tail shapes have been studied in depth. Graduated and pin tails have received less attention than forked tails, despite being more likely, in terms of aerodynamic theory, to be honest signals. We report morphological variation in live specimens of two sexually dimorphic passerines from the same site with different tail shapes: graduated (Cape sugarbird Promerops cafer ) and pin (orangebreasted sunbird Antobaphes violacea ). Coefficients of variation (CVs) were calculated for all morphological traits, both non-ornamental (range 1.91–5.72) and ornamental (range 5.83–21.71). Males and females did not differ in CV for any non…
Oral trichomonosis: Description and severity of lesions in birds in Spain.
2020
Este artículo se encuentra disponible en la página web de la revista en la siguiente URL: https://www.sciencedirect.com/science/article/abs/pii/S1383576920301264 This is the pre-peer reviewed version of the following article: Martínez-Herrero, M.C., Sansano-Maestre, J., Ortega, J., González, F., López-Márquez, I., Gómez-Muñoz, M.T. et al. (2020). Oral trichomonosis: description and severity of lesions in birds in Spain. Veterinary Parasitology, vol. 283, art. 109196, which has been published in final form at https://doi.org/10.1016/j.vetpar.2020.109196. Este es el pre-print del siguiente artículo: Martínez-Herrero, M.C., Sansano-Maestre, J., Ortega, J., González, F., López-Márquez, I., Góme…
Strong signature of selection in seeder populations but not in resprouters of the fynbos heathErica coccinea(Ericaceae)
2016
A higher frequency of natural selection is expected in populations of organisms with shorter generation times. In fire-prone ecosystems, populations of seeder plants behave as functionally semelparous populations, with short generation times compared to populations of resprouter plants, which are truly iteroparous. Therefore, a stronger signature of natural selection should be detected in seeder populations, favoured by their shorter generation times and higher rates of population turnover. Here we test this idea in Erica coccinea from the Cape Floristic Region, which is dimorphic for post-fire regeneration mode. We measured three floral traits supposedly subject to natural selection in see…
The roles of temperature, nest predators and information parasites for geographical variation in egg covering behaviour of tits (Paridae)
2020
Abstract Aim: Nest building is widespread among animals. Nests may provide receptacles for eggs, developing offspring and the parents, and protect them from adverse environmental conditions. Nests may also indicate the quality of the territory and its owner and can be considered as an extended phenotype of its builder(s). Nests may, thus, function as a sexual and social signal. Here, we examined ecological and abiotic factors—temperature, nest predation and interspecific information utilization—shaping geographical variation in a specific nest structure—hair and feather cover of eggs—and its function as an extended phenotype before incubation in great (Parus major) and blue tits (Cyanistes …
Pulchrosomapulchrosoma(Trematoda: Cathaemasiidae) in Ringed kingfishers (Megaceryletorquatatorquata) from Iquitos, Peru: with inferences on life-cycl…
2007
In the winter of 2001, four Ringed kingfishers (Megaceryle torquata torquata) were imported from Iquitos, Peru for the zoological garden Faunia in Madrid. Two individuals were necropsied, and infections by the digenean trematode Pulchrosoma pulchrosoma were discovered inside granulomas located in the lung, trachea and coelomic cavity. The life cycle of this trematode species is unknown. In one case the host maintained the parasite infection for at least 5 months, which represents a relatively long prepatency period. Moreover, the body locations in the hosts may suggest that the parasite is able to actively cross the lungs from the coelomic cavity to propagate.
Innovative and Applied Research in Biology: Proceedings, Vol.1
2019
Projekti: ZD2016/AZ81 & ZD2016/AZ107
Predator Mixes and the Conspicuousness of Aposematic Signals
2003
Conspicuous warning signals of unprofitable prey are a defense against visually hunting predators. They work because predators learn to associate unprofitability with bright coloration and because strong signals are detectable and memorable. However, many species that can be considered defended are not very conspicuous; they have weak warning signals. This phenomenon has previously been ignored in models and experiments. In addition, there is significant within- and among-species variation among predators in their search behavior, in their visual, cognitive, and learning abilities, and in their resistance to defenses. In this article we explore the effects of variable predators on models th…
Modeling temporal and spatial colony‐site dynamics in a long‐lived seabird
2003
We studied the determinants of colony site dynamics in Audouin's gull, Larus audouinii, breeding in a small archipelago of the western Mediterranean. Data on island occupation were available for a series of 25 years, since first colonization of the archipelago in 1973. Group behavior was studied in relation to the components of dispersal: permanence or abandonment (extinction) on an island previously occupied and permanence or occupation (colonization) of another island. Generalized Linear Mixed Models (GLMMs) were used to identify the relative contribution of each explanatory variable to the probability of colony abandonment. Gulls showed a low probability (3%) of abandoning one of the isl…
Barrier crossings and winds shape daily travel schedules and speeds of a flight generalist
2021
External factors such as geography and weather strongly affect bird migration influencing daily travel schedules and flight speeds. For strictly thermal-soaring migrants, weather explains most seasonal and regional differences in speed. Flight generalists, which alternate between soaring and flapping flight, are expected to be less dependent on weather, and daily travel schedules are likely to be strongly influenced by geography and internal factors such as sex. We GPS-tracked the migration of 70 lesser kestrels (Falco naumanni) to estimate the relative importance of external factors (wind, geography), internal factors (sex) and season, and the extent to which they explain variation in trav…
Life span, dispersal and age of nesting Great Grey Owls (Strix nebulosa lapponica) in Sweden.
2016
3,073 Great Grey Owls were banded in Sweden in 1955–2012. 416 were controlled at least once (54.6%) or recovered dead (45.4%). Three birds banded as nestlings were recovered in their 17th calendar year. Most birds were recovered during first year of life. Only 4 females were controlled breeding as 2CY birds. 91.3% of birds controlled as first time breeders were at least 4CY. Birds banded as nestlings and recovered dead between September and July moved 100.8 km (mean) with a median distance of 64 km. Juveniles controlled alive moved 45.9 km (mean) with a median distance of 23 km during first year of life. Maximum natal dispersal was 650 km. Median natal dispersal for females was 40 km, betwe…