Loon facts, status & studies

Lake Harvey residents:
If you see a loon in trouble please contact the following:

Eric Hanson, Vermont Loon Recovery Program, 802 586-8064, email: ehanson@vtecostudies.org

Lake Harvey Association Loon Committee at lakeharveyassociation@lakeharvey.com

Jan Parsons, chair, 802-633-2298, email: jpeacham@aol.com

You can learn more at http://www.vtecostudies.org//loons. From there you can get to various areas, such as the loon census reports for the last few years, and a number of categories, including "Rescue" which has a description of "Extreme Preening" probably because so many of us find it alarming when we see it.

For additional information See Our Loon Page under "You Can Learn More About Loons".


A Question and Answer With Eric Hanson

Q:

Hi Eric: the Harvey Lake loon chick was doing fine as of Tuesday evening Aug 23. I observed it for about a half an hour both Monday and Tuesday. On Monday afternoon parent and chick were diving and feeding along the shore near Frechette's Point and came very close to my kayak - a motionless kayak is not a threat evidently. But then the chick stopped diving and moved under a cedar tree along the shore line. About the time I noticed this, there was a big splash - another loon landed nearby. The parent went after it and the new arrival took off, "walking on water" out towards the middle of the lake. The parent came back and called the chick but it was back diving and was underwater.The parent went a distance away but then eventually came back and they resumed feeding. The parent did something similar the next evening, leaving the chick near shore while it went to the east shoreline to check out a loon which seemed to be minding its own business but must have been an intruder. While it was gone the chick stayed motionless but moved closer to shore when that loon took off making a great racket running across the water. Harvey Lake seems to get a lot of visiting loons. One morning in late July I had three land near my kayak well away from shore. They greeted each other with hoots, and then gathered in a flotilla and swam together up the lake. Another morning that week I saw a group of four swimming together.

At some point will the parents leave the chick to fend for itself against intruder loons? I have not seen the chick with both parents in a while. The chick is about eight weeks old. It is still getting a lot of attention and food from a parent. It can stay under water for about 45 seconds (as of a few days ago).

This is probably much more info than you need but the behavior of a loon family is fascinating to watch and listen to when they are communicating.. It is fun to try to interpret what is going on.

Jan Parsons

A:

Insights on Intruder Loons

Most people who have spent any length of time on a lake with breeding loons have witnessed visiting loons. The territorial pair usually confronts the “intruder”, sometimes resulting in aggressive behavior, failed nests, loss of chicks, and even adults killed in battle. These interactions can also look like a bunch of old friends hooting it up, so to speak. If chicks present, they usually go into hiding during the intrusion and survive quite well.

Who are these intruders and what are they doing? The intruder loons are likely conducting a territory assessment, which is especially important during the transition from prebreeder to breeder. Since 1992, Dr. Walter Piper has been conducting behavioral loon research in Wisconsin on nearly 100 lakes where most nesting loons are banded. There are now enough adults banded as juveniles (ABJs) returning to nest themselves that he has gained some insights into these intrusions. The research has focused around male loons because they usually return to breed within 10 miles of their natal lake; females disperse more widely.

Dr. Piper’s initial analysis indicates that loons are doing several things when they intrude into an existing territory.
1) Gaining Public Information: prebreeders are looking for evidence of successful breeding and then settling there. On 23 of 29 study lakes, intrusions were twice as frequent in the year after chick success compared to years after no chicks. Also, takeovers are significantly more likely to occur in a year following chick production. A takeover is when a challenging loon, male or female, kicks out one of the existing members of a pair. The other loon in the pair accepts the winner.
2) Gaining Site-Familiarity and 3) a Foothold: prebreeders make repeated intrusions into established territories to become familiar with them and gain benefits and a competitive advantage when he or whe gain ownership and/or when the owner leaves (e.g., dies or moves elsewhere). These are both likely occurring as young prebreeders tend to cluster their intrusions into a few adjacent lakes. We have observed this in Vermont where one lake seems to have many intrusions for a period of time, but then has several years with few intrusions.

Loons might also be 4) conducting a direct assessment of the physical and biological features looking for good breeding habitat or 5) looking for territories that resemble their natal lake territory. Dr. Piper does not think loons are settling passively on any lake or just looking for where loons are or are not (called conspecific attraction).

Dr. Piper has also revealed that age influences the mode of territory acquisition strongly in males. Three to 5 year-old males tend to found new territories in vacant lakes (peacefully), whereas 6 to 9 year-olds evict established males from their territories while in the peak of their physical condition. Old, displaced males go back to founding of new territories. In females, territory acquisition does not appear to be age-related.

Loons are long-lived, and territory acquisition is not a “one-shot deal”. Multiple motivations and assessments are likely occurring by loons when looking for and acquiring a spot in a territory. As more observations of banded loons are made, our understanding will continue to increase. And maybe, we’ll even begin to get some clues as to why big groups of loons congregate from July onward.


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