I spent about two hours (from 3-5 PM) watching the loons this afternoon. The temperature was about 70 deg. F and it was mostly cloudy. When I arrived at the lake there was a loon sitting on the nest. (S)he was alert and a bit pestered by the black flies.
Periodically the sun would peak out and the bird would open its mouth to “pant”. Avian “panting” is a thermoregulation mechanism. Birds don’t sweat. Thus, when they get hot the open their mouths to evaporate water from their mucus membranes in order to cool off.
After about an hour and a quarter, the loon stood up, examined the nest and settled back down facing in a slightly different direction. His/her movements looked a bit like egg turning, suggesting that at least one egg had been laid. Joan (who had arrived just a few minutes before this), using the spotting scope and a higher vantage point, confirmed that there is at least one egg (and possibly two) in the nest.
Thus the wait begins! The incubation period for loons is 25-30 days.
Roughly five minutes later and without warning, the loon on the nest slipped off the back of the nest into water. Shortly thereafter, the head of a bird appeared in a gap in the vegetation. It climbed up onto the nest, briefly examined the contents and sat down. I was puzzled by this turn of events until I finally noticed the head of a second loon just to the left of the nest. We had witnessed a ‘changing of the guard’! I had been completely unaware that the second loon had arrived at the nest. One of the hazards of peering into a telephoto lens is ‘tunnel vision’!
The loon in the water spent a few minutes moving nesting material towards the nest and then headed out to feed. After watching the sitting loon for a few more minutes, and knowing it could be an hour or more before the next changing of the guard, we packed up and headed home.
