Search results for "PASS"
showing 10 items of 1629 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…
Interspecific variation in the relationship between clutch size, laying date and intensity of urbanization in four species of hole-nesting birds
2016
Marie Vaugoyeau [et al.]
Geographical variation in egg mass and egg content in a passerine bird
2011
Reproductive, phenotypic and life-history traits in many animal and plant taxa show geographic variation, indicating spatial variation in selection regimes. Maternal deposition to avian eggs, such as hormones, antibodies and antioxidants, critically affect development of the offspring, with long-lasting effects on the phenotype and fitness. Little is however known about large-scale geographical patterns of variation in maternal deposition to eggs. We studied geographical variation in egg components of a passerine bird, the pied flycatcher (Ficedula hypoleuca), by collecting samples from 16 populations and measuring egg and yolk mass, albumen lysozyme activity, yolk immunoglobulins, yolk and…
Early developmental conditions affect stress response in juvenile but not in adult house sparrows (Passer domesticus).
2009
6 pages; International audience; The short- and long-term consequences of developmental conditions on fitness have received growing attention because the environmental conditions during early life may influence growth, condition at independence, recruitment, reproductive success or survival. We tested here, in a natural house sparrow population, if early conditions during nestling stage affected the stress response of the birds (i) shortly after fledging and (ii) next year, during their first breeding. We experimentally manipulated brood size to mimic different rearing conditions, creating reduced (-2 chicks) and enlarged broods (+2 chicks), while in a third group brood size was not manipul…
Clutch-size variation in Western Palaearctic secondary hole-nesting passerine birds in relation to nest box design.
2014
Møller, A.P. [et al.]
Effects of interspecific coexistence on laying date and clutch size in two closely related species of hole-nesting birds
2018
Co-existence between great tits Parus major and blue tits Cyanistes caeruleus, \ud but also other hole nesting taxa, constitutes a classic example of species\ud co-occurrence resulting in potential interference and exploitation competition\ud for food and for breeding and roosting sites. However, the spatial and temporal\ud variation in co-existence and its consequences for competition remain poorly\ud understood. 2.We used an extensive database on reproduction in nest boxes by\ud great and blue tits based on 87 study plots across Europe and Northern Africa\ud during 1957-2012 for a total of 19,075 great tit and 16,729 blue tit clutches to \ud assess correlative evidence for a relationship …
Phenological sensitivity to climate change is higher in resident than in migrant bird populations among European cavity breeders
2018
Many organisms adjust their reproductive phenology in response to climate change, but phenological sensitivity to temperature may vary between species. For example, resident and migratory birds have vastly different annual cycles, which can cause differential temperature sensitivity at the breeding grounds, and may affect competitive dynamics. Currently, however, adjustment to climate change in resident and migratory birds have been studied separately or at relatively small geographical scales with varying time series durations and methodologies. Here, we studied differential effects of temperature on resident and migratory birds using the mean egg laying initiation dates from 10 European n…
Gray plumage color is more cryptic than brown in snowy landscapes in a resident color polymorphic bird
2020
Abstract Camouflage may promote fitness of given phenotypes in different environments. The tawny owl (Strix aluco) is a color polymorphic species with a gray and brown morph resident in the Western Palearctic. A strong selection pressure against the brown morph during snowy and cold winters has been documented earlier, but the selection mechanisms remain unresolved. Here, we hypothesize that selection favors the gray morph because it is better camouflaged against predators and mobbers in snowy conditions compared to the brown one. We conducted an online citizen science experiment where volunteers were asked to locate a gray or a brown tawny owl specimen from pictures taken in snowy and snow…
Evidence of a highly complex phylogeographic structure on a specialist river bird species, the dipper (Cinclus cinclus)
2008
This study details the phylogeographic pattern of the white-throated dipper (Cinclus cinclus), a Palearctic, temperate, passerine bird that is exclusively associated with flowing water. Our results reveal a complex phylogeographic structure with at least five distinct lineages for the Western Palearctic region. As for many species of the Western Palearctic fauna and flora, this genetic structure is probably linked to the isolation of populations in different southern refuges during glacial periods. Furthermore, the isolation of populations in Scandinavia and/or Eastern regions, but also in Morocco and probably in Corsica, was accentuated by ecological and biogeographic barriers during Quate…
Innovative On-Site Adapted System for Fish Migration with Flow Divider and Glass Collector Basin
2020
Abstract The authors designed a new site-adapted fish passage system for upstream and downstream migration of small and large fish on the urban sector of the Bistriţa River. The longitudinal connectivity of this lotic system is interrupted by numerous transversal hydrotechnical works (weirs). This proposed system was designed to facilitate fish migration, promote fish recolonization of upstream and downstream habitats, allow the expansion of fish range, and increase spawning potential. All components of the proposed system are attached to a concrete girder located to the right stream bank, except a glass basin that is submerged in the riverbed. The positioning of the system in this girder e…