Malvern, Worcestershire, UK

From an overnight recording using a very inexpensive contact microphone secured under the roof of my garden pergola. Directly above is a hen mallard incubating eggs. Very luckily the mic must be under her body registering the pulse. The planking is 10mm thick. Notice how quickly her heart changes pace. Strangely other sounds are picked up too. Possibly the wooden roof is acting as a diaphragm as well as a conductor. You may have to increase the volume to hear this recording well. I am hoping to record the eggs hatching later around 17th April.