Regular ambient temperature monitoring provides data used to help calibrate thermal imaging videos as part of research into measuring stress levels in wild birds.
Researchers at Glasgow University are
developing a new, non-invasive method of measuring stress
in wild birds using thermal imaging. This new technique
avoids the difficulties of having to take blood samples to look at
plasma hormone levels. When animals are under physiological stress,
their blood gets diverted to the body core. This results in a
cooling at the skin surface, which is what the researchers are
studying as a new way of assessing stress state.
The absolute temperatures measured by the thermal
imaging cameras are affected by a number of factors, including air
temperature and humidity. The analysis software is
designed for this data to be inputted, but in practical terms it is
inconvenient to collect, and can introduce error. An alternative
method is to provide a reference temperature from a body
with known reflectance, within the field of view,
against which the whole image can be calibrated. A
temperature probe covered in insulation tape is
perfect for this job.
Talk 2 data loggers and accompanying probes are being
used in this way with cameras at a number of research sites in the
area surrounding the Scottish Centre for Ecology and the
Natural Environment (the University of Glasgow field
station), on the eastern bank of Loch Lomond.
Paul Jerem is a Researcher on the project whose
group has been using Tinytag loggers to successfully monitor
ambient temperature for many years. Paul comments, "As
the loggers were already providing the kind of data we needed for
calibrating the thermal image videos, it was suggested that I use
them. Their accuracy and the ease of use of the Tinytag Explorer software are the
main reasons I'm happy using them."
In order to increase stress levels in the birds, a stuffed
sparrowhawk is sent down a length of clothes line, picking up speed
as it approaches a busy woodland bird table, simulating a natural
attack. The thermal cameras record changes in bird body
temperatures as the perceived risk of predator attack
rises. The study aims to understand how animals are
responding to environmental change, particularly climate
The arrow on thermal image above shows the logger probe in
the top right hand corner (the slightly pale rectangle).