LMG_3139 Clune n Honey Return


As this beautiful photo by Linda Grenzer makes clear, time is passing. Chicks have matured and left their natal lakes, territorial pairs have scattered. Juveniles and adults alike are preparing to head south. Most obvious to loon watchers, adults have shed their striking breeding plumage and donned dowdy winter garb.

Although we might mourn the significant loss of beauty that occurs among loons in the fall, molting is a pragmatic biological pattern. Feathers wear out with time and use, requiring replacement, so seasonal molting of some kind is essential to survival. But why do loons lose the white wing spots, the necklace and chinstrap, and the elegant black head? As usual, the answer is that we cannot be certain without experimental investigation. However, these prominent features of the plumage signal readiness to defend a territory and to breed. Hence, they are inappropriate and possibly costly signals to send during the autumn. An adult that maintained breeding plumage during the fall might attract the attention of others and trigger territorial interactions at a time when it should be feeding vigorously in preparation for migration. Moreover, the contrasting breeding plumage would probably make a loon more conspicuous to predators such as sharks, which could be costly during a long winter on the ocean.

The two loons in Linda’s photo are her breeding male and female — and two of our best-known individuals. They appear often in her photos, such as when 5 intruders came to call and when they refused to abandon their nest, despite merciless black flies. After all they had been through this year, it was a surprise to see the male (Linda calls him “Clune”) and the female (“Honey”) spend a short time together on the brink of fall migration, long after most pairs had dispersed. I find this photo poignant somehow. I suppose it symbolizes to me this pair’s unwavering unified front in the face of all challenges and changes that confront them.

Great news! Our manuscript that describes natal site matching was just accepted for publication in a prestigious ecological journal. Very exciting to get the story out there that young loons have a strong statistical tendency to settle on breeding lakes that match their natal lake in both size and pH.

From the field….about half of our breeding pairs are now incubating eggs. Although blackflies are moderately bad, they do not seem to be terrorizing the loons enough to cause them to abandon their nests. I am anticipating a good year for reproduction in Oneida County. (Fingers crossed, as always.)

Many of the pairs I have observed on recent days have spent their time on the surface in a fruitless effort to shake or toss their heads to rid themselves of blackflies. Loons have their own dedicated species of blackfly, Simulium annulus, that depends on them for a blood meal prior to reproduction. Blackfly populations vary from year to year, and it seems pretty clear (though not scientifically proven) that the numbers of these nasty blood-suckers and their synchrony with nesting determines how many loon pairs abandon their nests in May. At this point, we have found seven loon pairs that have just initiated nests. I hope that this first wave of nests survives the blackfly infestation. In 1996, also an extraordinarily late year, abandonments occurred at a moderate rate (about 20%), but were not devastating, as in some years. So, I am optimistic that it could still be a good year for chicks, despite the lateness of ice-out.