As birds are a highly mobile group of animals, it is often difficult to obtain physiological, behavioural or ecological information from individual birds under natural conditions. To help address the difficulties of studying free-living animals, biologging technologies that use small ‘animal-borne’ recording devices have been developed. The technology started in the 1970s from simple time-depth recorders, and it has revealed the amazing diving abilities of seabirds. Now, the diversification and miniaturization of biologging devices offers unique opportunities to study various biological aspects of marine and terrestrial bird species. In this review, we explore recent advances in biologging technologies and its application to bird studies in the following major research themes: movement, foraging, biomechanics, physiology, cognition, social behaviour and external environment. Research highlights include the documentation of long-distance migratory movements, foraging strategies, optimized biomechanical output, energy-saving mechanisms, cognitive abilities, social interactions and environmental relationships over a wide range of bird species. Then, we discuss the current challenges and future directions in this field; the refinement of devices and attachment/retrieval methods; the development of analytical techniques suited for spatially- or temporally-correlated data; the incorporation of other individual-based research techniques, and the enhancement of multi-disciplinary studies. The scientific field of biologging will help integrate diverse research disciplines such as biomechanics, physiology, behaviour and ecology, to better understand the life of birds in their natural environments.

View full abstract

In the wild, seabirds dive longer than their theoretical aerobic dive limit (oxygen store divided by oxygen consumption rate). One of the potential explanations for this is that when descending in water seabirds regulate their foot or wing strokes to compensate their upward buoyancy, which decreases with the current depth to reduce oxygen consumption rate. The change in frequency of wing or foot stroke with current depths was compared between South Georgian Shag Notocarbo georgianus (SGSG), Common Murre Uria aalge (COMU), and Macaroni Penguin Eudyptes chrysolophus (MCPN) using biologging techniques. When descending to 60 m depth, the frequency of thrust and foot stroke decreased in SGSG, which make a forward thrust at each foot stroke. While in COMU, the frequency of thrust decreased, whereas wing stroke was nearly constant. COMU made a thrust with each up- and down-stroke in shallow water but only with each down-stroke in deeper water. In MCPN, however, the frequency of thrust did not change with the current depth. The MCPN made strokes at a nearly constant rate, while making thrusts with each up- and down-stroke at any depth. Because of the shallower descent angle of MCPN, compared with those of SGSG and COMU, MCPN should require relatively little thrust in order to compensate for its buoyancy and thus might not need to change the frequency of thrust with current depth. Swimming speeds during descent were nearly constant (1.4–2.2 m/s) in SGSG, COMU and MCPN. These three species appeared to regulate their strokes to maintain a range of swimming speeds. Biologging techniques reveal the biomechanical regulation of movement of birds under morphological and physical constraints. This provides a new approach to understanding the behavioural ecology of birds flying in the air and water.

View full abstract

Schmidt-Nielsen (1997) defined physiology as research into the functions of living organisms (how they eat, breath and move) and how they adjust to the adversities of their environment. Physiological ecology is research into how they adjust, or into ecological issues resolved using physiological methods. Endothermic animals do not use oxygen dissolved in water and lose body heat to cold water at a rate, 25 times faster than in air. So, living in water is an adverse environment for many animals. Auks and penguins are top predators in Arctic and Antarctic marine ecosystems and are excellent divers due to their ability to maintain high body temperatures. Enzyme activity increases with high body temperature contributing to the great power of their body muscles. However, it is unclear how small animals such as seabirds maintain high body temperatures when they dive in cold water. Recently, biologging techniques can record physiological parameters such as heart rates and, body temperatures. In this review, the physiological adaptations, for the trade off between oxygen sparing and body temperature changes, in diving Brünnich's Guillemots Uria lomvia are discussed. The study of physiological ecology in birds, using biologging techniques, is also discussed.

View full abstract

For sustainable use of marine resources, ecosystem based management is essential. However, collecting and integrating all the information needed is difficult. Thus it is important to use effective indicators of marine ecosystem change. Seabirds are believed to be useful biological indicators of marine ecosystem changes and marine pollution. In this paper, we review: 1) the responses of seabird to climate driven marine ecosystem changes, 2) the usefulness of seabirds as indicators of marine pollution and its potential effect on seabirds, 3) the status and conservation of albatrosses, focusing on the reduction of long-line by-catch. We review the seabird monitoring program globally and propose a seabird monitoring and network in Japan.

View full abstract

Japanese Quail Coturnix japonica populations were censused along one to three 2-km transects (a total of 928) situated in 823 quadrates (4.5 km×5 km), in central and southeastern Hokkaido from late April to late July, 1976–2009. Quails were recorded mainly from Yufutsu, Ishikari and Tokachi plains, and occurred in 10.4% of grasslands and 3.8% of agricultural lands censused. Agricultural lands in which quails occurred contained grasslands and/or wheat fields of 18–75% (average 47.1, SD 19.0). During the study, quails were recorded often until 1987 and from 1998 onwards, but were not recorded during 10 years from 1988 to 1997, except in 1991. Occurrence rates of quails decreased significantly from 6.7% during the 1970s and 9.0% during the 1980s to 1.7% during the 1990s, then increased to 5.6% during the 2000s.

View full abstract