Abstract:
Determination of avian nesting behavior is challenging for a number of reasons: accessing the nest
can be difficult, electronic recording devices are costly and may be damaged by the parents, and presence
of the device may disrupt normal parental behavior. External devices such as video cameras can
be used to record nesting activity, but these are expensive and labor intensive (i.e., every minute recorded
requires an equal amount of viewing time and encoding by the researcher) and so are not feasible
for long-term observations. Because the goal of avian incubation is to maintain the eggs at the
temperature suitable for optimal embryonic development, we investigated whether the use of thermocouples
placed in the nest could as a surrogate for nest attentiveness. We tested three types of thermocouples
for this purpose. Because zebra finches are prolific nest builders and will use any material
available for nest-building, an exposed thermocouple wire is vulnerable and could easily become
damaged. Therefore, we chose to disguise two of the thermocouples by embedding them in dummy
eggs and placing the eggs in the nest at the end of egg-laying. We emptied nonfertile zebra finch
eggs and experimented with filling them with different substances including agarose and a silicone
adhesive compound that, when cured, would secure the thermocouple in the egg and remain thermally
responsive. Testing with breeding zebra finches established that this device was well tolerated and
provided a good measure of incubation behavior.
