All Dressed Up and Nowhere to Go

Spring is on its way. As I twiddled with my phone just now to check conditions in the study area, the temperature was nine degrees warmer in northern Wisconsin than in southern California — the result of an unseasonably warm day in the study area and an unseasonably chilly one here in SoCal. At long last, the ice is melting, and loons will soon be back on their lakes. Meanwhile, as Linda’s photo shows, they gather in droves on open water. Being Linda, she also checked out their bands, yesterday and today, to see how many she could identify. We are all the beneficiaries of her tireless efforts, because her IDs provide a window onto the lives of returning breeders that are, for the moment, baffled in their efforts to reclaim their territories.

Who are these birds, and where are their territories? Are they males or females? Are they, in fact, breeders or young floaters, who lack territories and will spend the year challenging territorial residents for ownership? Are they migrants hundreds of miles from their breeding area or neighbors stopping by until their nearby lake becomes ice-free? We cannot answer all of these questions, but we can answer most of them based on Linda’s meticulous observations.

First of all, the loons in these aggregations are almost all males. Of the 12 birds positively ID’d by Linda, 10 are known males, one is a female, and one is of unknown sex. Linda suspected this herself: she reported numerous territorial yodels, sometimes by multiple males at once, as the birds rafted about in ice-free portions of the lake. Females must be only a few days behind; in fact, as I was writing this, Linda reported seeing a breeding pair near last year’s territory on Nokomis.

Second, loons present on the breeding grounds at the cusp of the seasons are mostly breeders that have come to reoccupy territories, rather than young floaters bent on evicting them. Only one ID’d loon from Linda’s list is a possible floater; all others are known breeders.

Third, loons that aggregate on ice-free water in early spring are a geographical smattering — many from neighboring lakes but a good many from farther north, whose lakes might not be open for a week or more. Linda’s sightings show this clearly, as her list includes breeding males from:

1) the adjacent Nokomis-East Central territory,

2) Indian Lake, which is 6 miles to the NE,

3) Soo Lake, 11 miles to the NE,

4) Silver Lake (Lincoln County), 8 miles S,

5) South Blue Lake, 16 miles to the N,

6) Miller Lake, 18 miles N,

7) Blue Lake-West Territory, 20 miles N,

8) Forest Lake (Vilas County), 40 miles NE,

9) Rock Lake (Vilas County), 50 miles N, and

10) Crab Lake (Vilas County), 50 miles N.

and a lone female from Burrows Lake, 10 miles NW.

What can we learn from these sightings? The preponderance of males confirms that males precede females on migration by at least a few days, and shows that males are the main ones bottlenecking on rivers and open lakes near their ice-locked breeding territories. Returning males push hard to return very close to the date that their lake becomes ice-free; females dawdle by a few days. Why it is so crucial for males to return as close to ice-out as possible is unclear, especially since the paucity of young, non-territorial birds present suggests that breeders are not likely to be challenged for territorial ownership in the first few days after settlement. Perhaps males, because they select the nesting site, return as early as possible to take note of any changes in the lake or shoreline over the winter that might require them to move the nest from the prior year’s site.

We can also discern that these early spring aggregations do not comprise neighbors reacquainting themselves after a winter apart, but individuals from far-flung lakes that do not know each other at all and are likely not to encounter each other again. While we should not be surprised by some tense moments between such unfamiliar individuals — it is, after all, spring and hormone levels are high — we should expect mostly peaceful loafing and feeding. These males simply have nothing to gain from battling unfamiliar loons.

In short, the rafts of loons in Linda’s photo are playing a waiting game. Since territory settlement is a time during which owners must defend their lakes vigorously — even if they do get a brief hiatus after settlement, owing the late return of young challengers — we would expect these males to do next to nothing until their lakes open up. They should feed, rest, and expend as little energy as possible before the onerous task of breeding begins.