silver spoon

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Following a long summer of capture, marking, and field observation, we have a new tranche of loon data from Wisconsin and Minnesota. The picture in Wisconsin does not change greatly from year to year. There we already had 32 years’ worth of research findings before 2025. But each successive year in Minnesota — where our research began in 2021 — increases our understanding of that population immensely. And with our improved knowledge of Minnesota loons, the status of the loon population across the Upper Midwest is coming into focus.1

Three demographic parameters together dictate whether a population of animals is increasing, decreasing, or stable, These factors are: 1) survival of breeding adults, 2) reproductive success, and 3) young adult survival. Recent measurements have shown us that the Wisconsin population is declining. And we know very well which of these parameters is responsible for the decline. If we compare our growing dataset in Minnesota to the trove of data we have from three decades of research in Wisconsin, we can learn whether or not Minnesota loons are headed in the same direction.

First, let’s look at survival of adult breeders. It should not be surprising that the most important single indicator of population dynamics (i.e. whether a population is stable, increasing or decreasing) is the rate of survival of its adult members. There is good news from the Wisconsin Study Area. The survival rates among territorial females and males both have been stable for the past three decades (Figure 1). This finding implies that once loons reach adulthood, they survive and hold their territories well. The decline that we are seeing in the Wisconsin population, then, must come about because of problems that occur before loons settle on territories.2

Figure 1. Annual survival rates of adult breeders on territories.

What about survival of territorial breeders in Minnesota? From measurements in 2022, 2023, and 2024, it appeared that adult survival in Minnesota might be lower than that in Wisconsin (look at these years in Figure 2, below). However, each year we get a better “read” on these numbers because our sample of loons becomes larger and more representative of the overall population. So the 2025 adult survival numbers are the most reliable ones we have to date. As you can see from Figure 2, there is no evidence for a

Figure 2. Survival rates of adult breeders in Wisconsin and Minnesota from 2022 to 2025. (Sample sizes are shown above each bar.)

difference in survival rates of territorial adults between Wisconsin and Minnesota. Minnesota, like Wisconsin, is seeing good adult survival. Again, this is good news!

Now let’s turn to reproductive success in the two states. Since we learned recently that the silver spoon effect is strong in loons, we know that we must look both at quality and quantity of loon chicks produced to get a good sense of how well a population is reproducing.

First let’s look at quantity. As Figure 3 shows, chick production in each region fluctuates greatly from year to year according to ice out date, severity of black flies, water clarity

Figure 3. Chicks fledged per territorial pair since 1995 in the Wisconsin Study Area and from 2021 to 2025 in the Minnesota Study Area. (Dotted line shows the trend in Wisconsin.)

in July, and other factors. Overall, however, chick production has decreased significantly in Wisconsin during the past three decades. Adult breeders are simply not producing as many offspring now as they did 30 years ago.

While Wisconsin data show a clear decline in number of chicks produced, it is too early to discern a trend in Minnesota. Chick fledging rate simply bounces around too much from year to year to see a pattern. We can say that chick production is at a similar level in the Wisconsin and Minnesota study areas. However, note that 2025 was a banner year for chick production in Minnesota and a poor one in Wisconsin.

Next we need to look at the quality of loon chicks that Wisconsin and Minnesota are producing. Our recent work has shown that chicks that fledge at low weights are much less likely to survive to adulthood and produce chicks themselves than are their heavier peers. Chick body condition has been falling for the past few decades in Wisconsin (see Figure 4, below).

Figure 4. Average body condition (mass divided by age) of chicks in Wisconsin from 1998 to 2025 and in Minnesota from 2021 to 2025. (Trendline shows Wisconsin pattern.)

The five years of data we have on body conditions of Minnesota chicks are not as many as we would like, but the numbers are consistent. Chicks fledge in Minnesota at similar — or even slightly worse — body condition than those in Wisconsin (Figure 4). We can infer that Minnesota is suffering from the same challenging chick-rearing conditions that have plagued Wisconsin (probably declining water clarity).

The third and final piece of the puzzle that we need to understand population dynamics is the survival of young adults. These birds are the breeders of the future that have not yet settled on territories. They range from three to about six years of age.

If you have been following my blog closely, you know that young adult survival of Wisconsin loons has seen the most dramatic decline among the three critical population determinants. That is, adult survival has held steady, and chick production has fallen somewhat, but the return rate of young adults to the breeding grounds has been abysmal — far below what it was a quarter century ago (see Figure 5, below).

Figure 5. Return rates of chicks to the breeding grounds 2 to 4 years after being banded as chicks in Wisconsin. (Data are missing for 2000 and 2007.)

We have been on pins and needles to see if this distinctive and rather alarming Wisconsin pattern is present also in Minnesota. Fortunately, our understanding of young adult survival has grown by leaps and bounds in Minnesota this year. Why? Because: 1) we started banding Minnesota chicks in 2021 and have done so every year since then, 2) most young loons return to the breeding grounds at three or four years of age in adult plumage, and 3) we regularly record identities of these young birds as intruders and loafers within our study areas. Thus, 2024 gave us our first glimpse at young adult survival in Minnesota using the crop of 26 chicks banded in 2021. And 2025 provided an even better window onto young adult survival there, since we could look at the return rate of 64 banded in 2021 and 2022 combined.

What do our findings show so far? In 2021, we banded 52 chicks in Wisconsin. Of these, 7 had returned as of 2025 (13.5%). We marked 28 chicks in Minnesota during 2021, and only one has so far been spotted as an adult (3.6%). For chicks banded in 2022, the numbers that have returned in Wisconsin and Minnesota, respectively, are 5 of 44 (11.4%) and 4 of 36 (11.1%).

These numbers tell a clear story. The percentage of young adult loons returning as adults in Minnesota is well short of that expected in a healthy population (a rate of about 41%). That percentage is also far below what we have seen in the past in Wisconsin (note the return rate in the 1990s and 2000s in Figure 5). In fact, the low return rate of young adult loons in Minnesota closely mirrors the dismal rate in Wisconsin.

In summary, it has taken five years to be confident of how the loon population in the Minnesota Study Area is faring. But our data now show that loons in Minnesota — at least those in Crow Wing and Cass counties, where we work — exhibit the same set of quirky demographic patterns that typify loons in Wisconsin and have set in motion a decline in the overall population there: 1) strong and stable adult survival, 2) poor reproduction in terms of both number of chicks and body condition at fledging3, and 3) a massive and diagnostic plunge in the survival rate of young adults (which are future breeders).

We have work to do.

1Thanks to Sheila Johnston, who took this photo of a molting adult loon on Gull Lake, which is just south of the Minnesota Study Area.

2I know. I just published a blog post in which I mourned the losses of many male breeders in the Wisconsin Study Area. I am still concerned about these losses. But in the long-term, which spans over three decades, adult males and females both have survived well. So I am hoping that the loss of several old, established male breeders this summer in Wisconsin was a blip.

3As noted earlier, it is too soon to tell from our data whether the number of chicks fledged is declining in Minnesota. We will gather those data over time. But we already know that Minnesota loon chicks are fledging in poor condition, just like Wisconsin loons. It is worth noting that the Minnesota Loon Monitoring Program, which has counted chicks across the state since 1994, reports a long-term and statewide decline in chick numbers.

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Twenty years ago colleagues and I published a paper showing that artificial nesting platforms increase loon’s hatching success by 70%. Others have reported similar patterns. So there is no doubt that, on average, loons that incubate their eggs on artificial nesting platforms (“ANPs”) put more chicks in the lake than do pairs using natural sites. Moreover, our paper showed that greater hatching success produced by ANPs also leads to more fledged loons.

In the last two decades, ANPs have become an enticing tool used by loon conservationists to boost loon populations. This is not surprising. ANPs have proven to be effective, and they are rather easy to make and place in the water. So conservationists can plop a mess of ANPs in the water and feel pretty confident that they have added young loons to the population. And they can make a strong case to funding agencies that their actions might help loons avoid population decline. Indeed, many millions have been/are being spent in the U.S. to float ANPs as a means to mitigate the negative effects that oil spills in the Gulf of Mexico have had on the species.

Are ANPs really just as good as natural sites at producing young loons that reach adulthood? Or are platform-raised chicks not as likely to survive to fledging age as chicks hatched as natural sites? We must remember that loons pick the location of a natural nest, whereas humans choose the site where platforms go. So it seems quite plausible that platform-raised young face hazards that natural-raised young do not.

It is only now that I have large enough samples of nests from platforms and natural sites that I can run a head-to-head comparison. Despite my 32 years of Wisconsin data, only a small proportion of loons in the Wisconsin Study Area (e.g. 15 of 90 focal pairs in 2024; 17%) nested on platforms. In Minnesota, however, almost half of all of our focal pairs use ANPs (38 of 84 territorial pairs in 2024; 45%), so our sample of platform-hatched chicks has swollen markedly since 2021.

As the graph above shows, hatchlings from platforms are lost slightly more often than are natural-hatched chicks in both states. While the pattern shows up in both Minnesota and Wisconsin, the difference is quite small and does not reach statistical significance. In other words, we have no scientific evidence that chicks hatched on platforms suffer lower survival than those hatched at natural sites. The same can be said for chick loss in Wisconsin versus Minnesota, despite what appears to be a slightly higher rate of chick loss in the North Star State.

Frankly, I am relieved! It has become almost de rigueur to place an ANP in your lake to support the loons. If, for some reason, ANPs had been producing chicks likely to perish before reaching adulthood, it would have sent shockwaves through the world of loon conservation.

I am still not a great fan of nesting platforms. Why not? Because we have learned in recent years that nest predation is not the main problem loons are facing in the Upper Midwest. Remember, nesting platforms are a one-trick pony. They increase hatching success enormously and put more chicks in the water. But if chicks cannot get enough food to survive to adulthood or reach prime condition, then all of the platforms in the world will not help them.

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The Silver Spoon Effect occurs when individual animals that experience favorable circumstances early in life — like abundant food — enjoy long lives and produce many offspring when they reach adulthood. In essence, growing up well-fed places a young animal on a track to become successful as an adult.

The Silver Spoon Effect is strong in loons of the Upper Midwest. How do I know this? I have just done a massive analysis of factors associated with return to the breeding grounds among loons banded as chicks. I learned that chick mass (adjusted for age) is the single strongest predictor of both survival to breeding age and breeding success. That’s right: a loon’s mass as a chick accurately predicts how long it will live and how many young it will raise.

This does not mean that a loon chick that grows up without adequate food is guaranteed to die young and raise no chicks. Nor does it mean that a fat, healthy chick is certain to survive to adulthood and have many offspring. After all, it is a statistical pattern. But body mass in chicks is a very strong predictor of lifelong success. The graph below shows the effect.

Loons that did not survive to breeding age tended to be those with low mass as chicks (top row). Loons that survived to return to the breeding ground but never raised young (middle row) tended to be of intermediate mass as chicks. Loons that became successful breeders were mainly those that had been heavy as chicks.

It is hard to know how to feel about the Silver Spoon Effect. On the one hand, it seems cruel. One would love to think that a loon chick could overcome a rough start and turn its life around. But such a turnabout rarely happens. A juvenile that struggles to get enough food in its first month might make its first migratory flight to Florida. However our data show that such a loon has very low odds of surviving beyond its first few years.

On the other hand, loons reared with a silver spoon become the reproductive pillars on which the population’s persistence depends. Take the Pickerel-West male pictured in Hayden Walkush’s photo above. This male — “yellow over white-blue, auric red over silver” (Y/Wb,S/Ar in the table below) — was 8% heavier than average when we captured him on Tom Doyle Lake on August 3rd, 2013 with his parents and younger sister. He was then five weeks old. The momentum that his parents built for him gave him good odds of surviving to adulthood, settling on a productive territory, and rearing young himself. Indeed, he has already fledged six chicks on Pickerel with two different females despite being only eleven years old.

“Yellow over white-blue” is not exceptional. In the table below, you can see the list of all of our recent Wisconsin breeders that were marked as chicks. (Most are males because of the much shorter range of natal dispersal by males.) Pay particular attention to the right-hand column (“% above avg”). A “0” in this column indicates that this loon was of average mass for its age as a chick. If this were a random set of loons, the red numbers would all fall around zero; some a bit negative, some a bit positive. In fact, the table looks like something from Lake Wobegon: almost all territorial breeders in our study area were well above average mass at the chick stage. Sixty-five percent were absolute whoppers — 20% or more above average mass. This is a good illustration of the strength of the Silver Spoon Effect. (The pink-shaded cells show the few current breeders that were of below-average mass as chicks.)

Breeding lake, natal lake, band combination, sex, Chick Mass Index, and % difference from population average for current breeders in the Wisconsin Study Area.

The table shows something clearly. Territory settlers are the cream of the crop. Yes, there are a few overachievers — Harrison Flowage, Manson, Nose, Sherry, Silverbass and Soo. But their small number speaks to the strength of the pattern.

Leaving aside the fascinating and often brutal nature of silver spoons, let’s look at the implications of the pattern for loon conservation in the Upper Midwest. If you recall, the young adult “die-off” that we have found there is the most troubling aspect of the current population decline. Put simply, we are losing the vast majority of all young adults between the time they leave the breeding grounds as juveniles and return to it as adults 2 to 4 years later. This mortality must occur at some stage(s) of the life history of young loons — like migration or winter — that we have not studied well.

Average +/- standard deviation for Chick Mass Index from 1998 to 2020.

Here is the critical point. I have been suggesting that a decline in habitat quality along the migration route or on the wintering ground in Florida might be responsible for the die-off of young adults. But look at the graph above. Chick Mass Index has slid downwards steadily during the past quarter century. This means that the number of loons “fit” enough to survive to adulthood, claim territories, and rear chicks has also declined steadily. So loons are likely not dying because of environmental degradation on the migratory path or in Florida. Rather, loons themselves are of poorer quality than they were 15-20 years ago owing to limited food they received as chicks and can no longer survive the same challenges as well they used to.

Thus, the Silver Spoon Effect forces us to confront an uncomfortable reality: factors on the breeding grounds — during the chick-rearing period — are almost certainly contributing strongly to population decline. We cannot blame Florida.

But the silver spoon has a silver lining. Why? If we can improve lake conditions in Wisconsin and Minnesota so that loon parents can feed their chicks amply each July and August, we can help them raise fit chicks. And those fit chicks will grow up to become robust, successful breeders and strengthen the population.

So the answer, after all, lies in the lakes of the Upper Midwest. And my current push to discover the exact cause of water clarity decline in Minnesota and Wisconsin lakes suddenly takes on even greater importance.

$20,000 Match from a Wisconsin Foundation

If you have already donated to support our work, thank you! If have not yet done so recently, this would be a great time. Earlier this week we learned that a northern Wisconsin foundation will match every dollar raised from other sources up to $20,000. So every dollar that folks are able to donate will add $2 to our 2025 research fund.

DONATE HERE

We would dearly love to take advantage of this opportunity and field a strong research team next year. Thanks in advance, if you can help!