Flying is among the most energetically demanding behaviours in birds [ 5, 6 ]. By analysing the mechanical and physiological aspects of flight, we can gain deeper insights into how birds interact with their environments and how they may respond to conserve energy [ 7 ]. Using miniaturised data-loggers [ 8 ] attached to birds( Figure 4) we track their movement patterns during flight( Figure 5), both within the controlled wind tunnel environment and during free flight in the wild.
tape to the feather stumps. The bio-logger is then hooked on to this patch. This system ensures the device remains secure for the duration of the study, yet can be easily removed afterwards. The surgical glue allows for a temporary, non-invasive attachment that naturally sheds after approximately 2 weeks.
This procedure, while delicate, is well tolerated by the birds due to the strong bond I have built with them. The birds are accustomed to handling from a few days of age or since hatching, and my relationship with them is based on consistent care, familiarity and mutual trust. As a result, they exhibit minimal signs of stress or discomfort during bio-logger attachment or handling, enabling accurate and reliable data collection. The birds in our care are not merely subjects of research; they are integral partners in the scientific process, and their wellbeing is always our priority.
Another pivotal aspect of my role is helping to oversee the day-to-day operation of the wind tunnel facility, where much of our experimental work on avian flight dynamics is conducted. The wind tunnel is equipped with a three-dimensional infrared motion capture( MOCAP) system that tracks the precise movements of birds in flight, capturing the fine details of their wing-beat kinematics, flight trajectories and manoeuvres.
Figure 4. A pigeon prepared for free-flight testing with a taped-on backpack device.
To gather this data, I fit the birds with reflective markers at specific anatomical locations. The MOCAP data, when combined with the accelerometry readings from the bio-loggers, provides information on how birds respond to environmental variables such as wind speed, air density and turbulence [ 9, 10 ]. Additionally, direct measurements of carbon dioxide output during flight or while resting allow more precise estimations of metabolic costs [ 11 ].
These experiments have included an interesting field trip to trial equipment on larger species of birds( Figure 6) at the International Centre for Birds of Prey in Gloucestershire. Our work has featured in the television documentaries Birds [ 12 ] and Da Vinci ' s Dream: The Secrets of Flight [ 13 ], and is also on YouTube [ 14 ].
Figure 5. A pigeon flying in the test section. Note the backpack device( circled).
Our bio-loggers are lightweight devices that monitor a bird ' s movement. They are carefully attached to the birds to ensure minimal impact on their flight characteristics. The devices are placed between the scapulae, directly over the bird ' s centre of gravity, ensuring balance and comfort during flight.
To attach the bio-loggers, we use either 3M Transpore or Micropore tape to secure the device to the feathers, or, alternatively, we trim the contour feathers and apply surgical glue to attach a small patch of hook-and-loop
Figure 6a. Field trip to test respirometry equipment. L – R: Dr Kayleigh Rose, Swansea University; Ashley Lawson, falconer at the International Centre for Birds of Prey, holding a bald eagle( Haliaeetus leucocephalus); the author.
56 Veterinary Nursing Journal