It is demonstrated that birds show wingtip path coherence when flying in V positions, flapping spatially in phase and thus enabling upwash capture to be maximized throughout the entire flap cycle, and suggested that birds in V formation have phasing strategies to cope with the dynamic wakes produced by flapping wings.
It is concluded that the increase in metabolism led to the use of endogenous energy reserves because the birds reduced rather than increased their food intake rates, and as a result, the barnacle geese lost body mass during wing moult.
It is concluded that by erecting structures such as wind turbines, which extend into open airspace, humans have provided a perceptual challenge that the vision of foraging vultures cannot overcome.
Applying a metaanalytical approach, recent studies of birds have shown that externally attached devices can have negative effects on nesting productivity, clutch, and the “rule” is often broken.
This study studied the flight behavior of a flock of juvenile Northern bald ibis (Geronticus eremita) during a human-guided autumn migration and shows that direct reciprocation can enable cooperation between animals in a natural context.
Seven hypotheses are identified, which address how the interaction of eggshell pigments and the light environment may influence embryonic development, including thermo-regulation; UV-B protection; photo-acceleration; lateralization; circadian rhythm;photo-reactivation; and antimicrobial defence.
The breeding ecology and life history-dependence of eggshell pigment concentrations in these comparative analyses implies that related species share pigment strategies, and that those strategies relate to broad adaptive roles in the evolution of variation in avian eggshell coloration and its underlying mechanisms.
The results reveal that it is not appropriate to simply assume in these two avian species that refl ectancebased eggshell colour measures are a suitable proxy for eggshell pigment concentrations or can be used as consistent predictors of maternal reproductive investment, and the need to assess and validate the strength and direction of the statistical relationships between egg shell colour measures, pigment concentrations, and maternal resource deposition in the egg for other species of birds.
A meta-analysis of 183 estimates of device impact from 39 studies of 36 species of bird designed to explicitly compare the effects of externally attached and surgically implanted devices on a range of traits, including condition, energy expenditure and reproduction concludes that device implantation is preferable to external attachment.
The authors identify a strong positive relationship between mass and metabolic rate among insects, fish, amphibians, reptiles, birds and mammals, and show that the genetic and interspecific correlations between these traits are consistent with a pattern of multivariate selection.