NOTES ON HOLE SIZE: 1  per Bergmann's rule, some species of birds may be larger in colder climates-e.g., a Canadian starling may be bigger than a Florida starling, thus the Canadian bird might not be able to fit in a certain hole size that its southern version could squeeze into.
A heart palpitation is the sensation that your heart has skipped a beat or added an extra beat. It may feel like your heart is racing, pounding, or fluttering. You may become overly aware of your heartbeat. This sensation can also be felt in the...
Heart palpitations. Palpitations are feelings or sensations that your heart is pounding or racing. They can be felt in your chest, throat, or neck. The heart's rhythm may be normal or abnormal when you have palpitations. Normally the heart beats 60 to 100 times per minute. The rate may drop below 60 beats per minute in people who exercise routinely or take medicines that slow the heart.