| composition of an avian guild in spatially structured habitats supports a competition-colonization trade-off. | assuming better colonization abilities of inferior competitors, the competition-colonization trade-off (ccto) is one of the hypotheses that explains spatial variation of species composition in fragmented habitats. whereas this mechanism may structure some plant and insect communities, ecologists have failed to document its operation in other natural systems, and its generality has been questioned. we combined fieldwork and published data to study the composition of a guild of passerines (parus c ... | 2007 | 17389222 |
| ecological plasticity by morphological design reduces costs of subordination: influence on species distribution. | we studied the feeding behaviour of two subordinate tit species (parus spp.) in two competitive contexts: feeding solitarily versus feeding in the presence of the dominant great tit. considering ecological plasticity as the within-species component of mean behavioural performance associated with different morphologies in different species, we test the hypothesis that subordinate species with morphological designs allowing a greater ecological plasticity (e.g. blue tit whose hindlimb morphology i ... | 2001 | 28547406 |
| evolution of enlarged body size of coal tits parus ater in geographic isolation from two larger competitors, the crested tit parus cristatus and the willow tit parus montanus, on six scandinavian islands. | here, we report that on six widely separated scandinavian islands, the coal tit parus ater has evolved morphologically in the direction of two absent competitors, the crested tit p. cristatus and the willow tit p. montanus, to the effect that it is up to 10% larger in linear dimensions than conspecifics on the adjacent swedish mainland, where all three species coexist. the large size is genetically determined, as ascertained by clutch exchange experiments between island and mainland nests. we co ... | 2015 | 26490673 |
| does day length affect winter bird distribution? testing the role of an elusive variable. | differences in day length may act as a critical factor in bird biology by introducing time constraints in energy acquisition during winter. thus, differences in day length might operate as a main determinant of bird abundance along latitudinal gradients. this work examines the influence of day length on the abundance of wintering crested tits (lophophanes cristatus) in 26 localities of spanish juniper (juniperus thurifera) dwarf woodlands (average height of 5 m) located along a latitudinal gradi ... | 2012 | 22393442 |
| seasonal dynamics of resource partitioning among foliage-gleaning passerines in northern finland. | the five most abundant species were included in a year-round study with respect to six foraging niche dimensions. approximately full multidimensional utilization functions were used for niche metrics. during summer foraging overlaps were invariably high, but in other seasons periodically lower. foraging site breadth was lower in winter, when fewer sites are profitable for foraging than in summer. feeding posture versatility, by contrast, was highest in winter. seasonal foraging shifts were very ... | 1980 | 28309529 |
| reproductive cost, age-specific survival and a comparison of the reproductive strategy in two european tits (genus parus). | theoretical analyses of optimal reproductive rates usually assume a trade-off between offspring production and parental survival. this study verified a survival cost for willow tit males; nonbreeding males survived better than males attending a brood. theory also predicts a smaller clutch size in birds that are less successful in transforming reproductive investments into mature offspring. as predicted, we found that crested tits, suffering a higher nest predation rate, laid smaller clutches tha ... | 1986 | 28564125 |
| egalitarian mixed-species bird groups enhance winter survival of subordinate group members but only in high-quality forests. | only dominant individuals have unrestricted access to contested resources in group-living animals. in birds, subordinates with restricted access to resources may respond to intragroup contests by acquiring extra body reserves to avoid periods of food shortage. in turn, higher body mass reduces agility and increases predation and mortality risk to subordinates. birds often live in hierarchically organized mixed-species groups, in which heterospecific individuals are considered to substitute for c ... | 2020 | 32132547 |
| divergent and parallel routes of biochemical adaptation in high-altitude passerine birds from the qinghai-tibet plateau. | when different species experience similar selection pressures, the probability of evolving similar adaptive solutions may be influenced by legacies of evolutionary history, such as lineage-specific changes in genetic background. here we test for adaptive convergence in hemoglobin (hb) function among high-altitude passerine birds that are native to the qinghai-tibet plateau, and we examine whether convergent increases in hb-o2 affinity have a similar molecular basis in different species. we docum ... | 2018 | 29432191 |