... the turn of the century. A particular challenge is the effect of scaling on flapping wing designs (i.e. ornithopters, from the Greek: ornis, meaning bird; pteron, meaning wing). At very large wingspans, flapping becomes impractical owing to changes in the flow physics at higher Reynolds numbers...

... the bill, given that body condition influences the surface temperature of another body region (the eye region). We measured the surface temperature of the bills of song sparrows ( Melospiza melodia ) before, during and after handling by an observer at 37°C ambient temperature. We fed five birds...

... and waking during daytime were weaker in winter than in summer. During daytime in winter, there were many instances where the birds were awake but not moving. Experimental sleep deprivation had no effect on the strength of the correlation between activity scores and EEG-based wake time. Overall, hourly...

... specialist. Behavioural acuity Interaural time difference Interaural level difference Bird Perceived physical cues Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659 EXC2177 Sound localization supports communication in both humans and animals...

...Amanda M. Palecek; Megan V. Novak; Richard W. Blob ABSTRACT Wading behaviours, in which an animal walks while partially submerged in water, are present in a variety of taxa including amphibians, reptiles, mammals and birds. Despite the ubiquity of wading behaviours, few data are available...

... on either side of it. Twelve birds (four per treatment) were randomly selected and killed by cervical dislocation at 42 days old to analyse the fatty acid profiles of their cerebral hemispheres and determine whether the levels of n-3 LCPUFAs in their blood reflected an accretion in their brain...

... received less attention. In birds, asynchronous hatching creates challenging developmental conditions for the last-hatched chicks, but differential allocation in last-laid eggs might help to compensate this initial handicap. The relative importance and potential interaction between pre- and post-hatching...

... of offspring TL results from intertwined effects of variation in TL of parental gametes, re-setting of the TL in the zygote at fertilisation, effects of parental (most often paternal) age and epigenetic or epigenetic-like inheritance ( Bauch et al., 2019 ; Eisenberg, 2019 ; Entringer et al., 2018 ). In birds...

...Tatiana S. Filatova; Denis V. Abramochkin; Holly A. Shiels ABSTRACT Birds occupy a unique position in the evolution of cardiac design. Their hearts are capable of cardiac performance on par with, or exceeding that of mammals, and yet the structure of their cardiomyocytes resembles those of reptiles...

... aerodynamics; if they act in the same plane, lift from the tail might compensate for lift lost over the fuselage (body), reducing induced drag with a more even downwash profile. However, textbook aeronautical principles should be applied with caution because birds have highly capable sensing and active control...

...) initially developed by Cawthon and collaborators ( Cawthon, 2002 ) (see also Criscuolo et al., 2009 ) for a full description of the principle and general methodology applied to two bird species). Specific amplification of a reference gene that was non-variable in copy number among individuals (see Smith...

... for a given species and its usefulness – relative to other localization cues – has been a powerful selective force in the evolution of the neural circuits involved. Birds and other non-mammals have internally coupled middle ears working as pressure-difference receivers that may significantly enhance ITDs...

... but data for birds remain scarce. We tested the hypothesis that colonization of germ-free chicks from a quail line selected for a high emotional reactivity (E+) with GM from a line with low emotional reactivity (E−) would reduce their emotional behaviour in comparison with germ-free chicks from an E+ line...

... with computer modelling reveal that close clustering of cSR along the Z-line is vital for rapid propagation of the Ca 2+ signal, enabling strong, fast contractions of the avian heart. Bird Chicken Computational model Calcium diffusion Electron tomography Peripheral coupling The four...

... release remains low until a threshold level of mitochondrial inactivity is exceeded. Free electron leak ROS/ATP ratio Oxidative phosphorylation Reactive oxygen species Skeletal muscle Starvation Bird Many physiological mechanisms, such as modulation of lipid mobilization and oxidation...

... technologies making navigational experiments on long-distance migratory and other wild birds much more accessible; the almost complete loss of the historically dominant, large-scale pigeon loft/research facilities; and prohibitive university per diem costs as well as animal care and use restrictions...

...Glenna T. Clifton; Andrew A. Biewener ABSTRACT Loons (Gaviiformes) are arguably one of the most successful groups of swimming birds. As specialist foot-propelled swimmers, loons are capable of diving up to 70 m, remaining underwater for several minutes, and capturing fish. Despite the swimming...

...Heather E. Watts; Daniela Jimenez; Veronica Pacheco; Tauras P. Vilgalys ABSTRACT Temperature-correlated shifts in reproductive timing are now well documented in numerous bird species. However, whether temperature directly influences reproductive timing or whether its effects are mediated...

...Alex M. Champagne; Victoria A. Pigg; Heather C. Allen; Joseph B. Williams ABSTRACT To survive high temperatures in a terrestrial environment, animals must effectively balance evaporative heat loss and water conservation. In passerine birds, cutaneous water loss (CWL) is the primary avenue of water...

...Monica A. Daley; Aleksandra Birn-Jeffery ABSTRACT Birds provide an interesting opportunity to study the relationships between body size, limb morphology and bipedal locomotor function. Birds are ecologically diverse and span a large range of body size and limb proportions, yet all use...