A Dramatic Summer on "Loon Pond", NY
The loons on Loon Pond started the breeding season in typical fashion. The banded male and the banded female who have been mates since about 2018 made a nest on an island and were incubating two eggs by May 30.
On June 12 things got interesting, and the summer of 2024 became the most remarkable summer in my 14 years monitoring Loon Pond.
The banded male was on the nest incubating the eggs. The nest faced the west, shallow end of the pond, and a loon that was sitting on the nest was not able to see what was going on in the main part of the pond because the island was in the way. In the deeper, main part of the pond east of the island, the banded female was resting with a visiting loon. This visitor was another mature male with a slightly down-curved upper bill that made him identifiable. He was not banded. He cooed a lot and stayed close to the female, and it looked like courtship behavior. The female did not coo back, but neither did she try to stay away or try to drive away this intruder. When I left the pond, the female was resting a few feet from this new male, while her mate incubated the eggs. I don’t think both males had been able to see each other and were probably unaware of the other’s presence. I expected them to fight and for the banded male to drive the intruder off when they discovered each other.
The unbanded male loon yodels and swims with the banded female on Loon Pond.
On June 18, the banded female was on the nest. Astonishingly, the new unbanded male was on the pond, and the old, banded male was gone. The new male with the down-curved bill had taken over as the territorial male, and the female was now his mate. A fight must have ensued, and it must have been a doozy, because the banded male had a lot to fight for: his mate, his unborn offspring, and his territory of the past six years. Was he still alive, and if so, where was he? Would the new male kill the chicks if they hatched, since they were not his offspring? Would the female be able to incubate the eggs alone, since this new male had no reason to help tend another male’s eggs?
I couldn’t wait to return. On June 26, the female was still incubating. It was almost time for the eggs to hatch. The new male swam behind the island to the nest, and the female pushed off the nest and joined him. They both swam out to the main part of the pond. There were still two eggs in the nest, but the female spent the next half hour out on the main pond with the new male and had not returned to the nest when I left. The eggs may have gotten chilled during the period of solo incubation, since the female would have needed breaks to feed and preen. Normally the male and female loons take turns incubating throughout the day and night. Were the eggs still alive?
The unbanded male loon incubates the previous male’s nest.
By June 30, at least one and probably both eggs should have hatched if they were still viable. I first noticed the female loon in the middle of the pond, resting alone. But where was the new male? Or any male? Had both the old, banded male and the new unbanded male vacated the territory of Loon Pond? Sadly, I paddled down toward the island to check on the nest, figuring that either the eggs had been predated or they were dead and now abandoned. Usually, I go slowly and quietly so as not to disturb a loon on the nest, but since the female was out in the middle of the pond, I cruised behind the island quickly. What I saw made me gawk and backpaddle in a hurry. There was a LOON on the nest!
Who could it be? Did the old male return and resume incubating his eggs? The new male wouldn’t incubate another male loon’s eggs, since he had no reason to invest energy in potential offspring that were not his. In fact, some male loons that take over another male’s territory will kill the chicks of the previous male. Also, the new male probably hadn’t mated with the female, hadn’t selected the nest site, or helped build the nest, so the whole sequence of events leading up to incubation were missing.
The loon was in hangover position, indicating stress, but he soon relaxed and picked up his head. When he did, I could see the characteristic slight downward curve of his upper beak. It was the new male, and he WAS incubating the old male’s eggs! There had not been enough time between my visits for the loons to have renested because it takes well over a week for a female to be able to lay another egg after losing her first clutch, so these had to be the original eggs.
The female loon swam down to the island, checked on her mate on the nest and me watching him, and then returned to the main pond. Now she had a helper for incubation duties. But was it too late, or were there tiny chicks hiding under the male’s belly?
Curiosity was burning in me, and I returned two days later on July 2nd. Once again, the female was in the middle of the pond, and the new male was on the nest. But by now it was over a month since I first found the loons on the two eggs, so the eggs had to be dead. Loons cannot tell when their eggs have died and will incubate sometimes for weeks past the time that they should have hatched. As I often do, I paddled to the far west end of the pond looking for other wildlife, and much to my surprise, I spotted another loon lurking near the small dam. I had never seen a loon this far down in the shallow end of the pond before. What loon could it be?
Loons socializing in a group on Loon Pond. When they are not nesting or raising chicks, loons enjoy the company of other loons.
Upheaval on Loon Pond created interesting social dynamics for field staff member Ellie George to observe.
I sat in my canoe and waited, and eventually the loon started swimming toward me. It did not seem afraid of me, and when it got close, I saw a flash of white on one leg. The old, banded male had returned! Later I was able to see all his bands and confirm his identity, but right now he had a dilemma. He wanted to get out to the main pond but had to sneak past the new male on the nest first. He dove and swam underwater all the way out into the main pond, and the new male did not see him. Out on the main pond, the old male swam to the female, and they looked at each other but did not vocalize. Then they both dove and surfaced in a penguin dance, both standing on the water by rapidly treading with their feet in an aggressive display. After this, each loon kept its distance from the other. The female was not in the mood to accept her old mate. I paddled back to the nest, and the new male was still incubating. I spotted an egg in the water not far from the nest and fished it out. It might have been accidentally kicked out of the nest or dropped in the water by a predator. It was cold, indicating that it had been in the water for a while, so I collected it for lab analysis.
Four loons were swimming together in the east end of the pond on July 7th. The banded female was near her unbanded new mate, and the old, banded male was swimming near another unbanded loon. All four loons swam and dove together, and after some time the banded male and his unbanded acquaintance took flight and left the pond. I checked the nest, where I found the one egg still on it, but the egg was cold and not being incubated. I marked it with a penciled X so I would be able to ascertain whether it was being turned and incubated before I collected it for lab analysis on my next visit.
The morning of July 15 found three loons present: the banded female with her new mate in the west end and the old, banded male alone in the east end. He tried to avoid the new male, while the new male searched for him. The old male took flight, flew two laps over the pond, and re-landed in the west end. While he flew, the new male yodeled at him. The nest was empty, no egg or eggshells. I took down the nest camera.
On July 19th I went searching for the old, banded male. I had a hunch that he might have moved to a pond just to the northeast, North Pond. This pond is similar in size but much more oligotrophic – meaning it is abundant in oxygen but relatively low in plant nutrients – than Loon Pond, and did not have a territorial loon pair, just occasional visiting loons. I located three loons together, and one of them had white bands! The banded male was there, interacting with two unbanded loons. When the unbanded loons took flight, the banded male yodeled, indicating he considered himself to be the territorial male on the pond. He also floated high on the pond with his tail cocked up when he was interacting with the other two loons, another sign of dominance and territorial ownership.
However, on July 20th, the annual loon census, the banded male was back on Loon Pond in the far east end, the only loon on the pond. But just before 8:00 AM, the banded female and her unbanded new mate flew in and landed in the west end. No interactions occurred between these loons. At 9:15 another unbanded loon flew in and landed, followed by another.
Once again, the old, banded male was on Loon Pond in the far east end on July 22. The unbanded new male and the banded female were present in the west end. The female hooted and another unbanded loon flew in and landed, and this loon interacted with the territorial pair. The female was most interested in this new loon, so the visitor was very likely a female. The old, banded male avoided interacting, and all four loons were still there when I left.
Then the situation changed. By July 31, only the territorial pair of the banded female and new male were on Loon Pond. It rained hard and I watched the water bead up and roll off the backs of the loons. It rolled off my raincoat and filled the bottom of my canoe and I left.
August 13th found only the territorial pair in the east end, hooting and giving short wails each time they surfaced. There was no sign of the old, banded male.
The unbanded male loon performs a display of aggression that researchers call a “penguin dance.”
A visit on September 1 after the official loon monitoring season ended had an exciting social gathering of five loons. It is common for loons to leave their territorial ponds and lakes in late summer and visit other lakes with loons, sometimes forming groups of twelve or more. Usually these are nonaggressive since hormone levels are dropping, and loons are actually social birds during the nonbreeding season. However, this loon gathering was a tense one, with two episodes of penguin dancing breaking out, and some loons wing rowing away. The territorial pair of the banded female and new, unbanded male were there, but the old, banded male was not. The other three loons were unbanded visitors. No actual fighting occurred, but lots of splash diving showed the tensions among these loons When one of the visitors took flight, the new male yodeled.
What will happen next year? Will the old, banded male return first and try to retake his territory? Or will the new male return and again be the dominant loon? Will the two males meet and fight? Will the old, banded female survive the winter and return for at least her 24th consecutive nesting season on Loon Pond? Will the territorial pair have a successful nesting season and add a couple more chicks to the female’s impressive list of offspring? I will be very excited to return as soon as the ice goes out next April to find out.
Words & Images by Ellie George, ACLC Field Staff & Loon Naturalist