The life of a field biologist, while offering the undeniable perk of spending time outdoors in stunning locations like Wisconsin, is not without its inherent risks. There’s a unique thrill in embracing the unpredictable nature of fieldwork, where meticulous planning often takes a backseat to spontaneous events. However, beneath the surface of this professional allure lies a constant undercurrent of peril. Despite my extensive research and the support from esteemed institutions like the National Science Foundation, Chapman, and the U.S. Geological Survey, which provide essential leg bands, a profound sense of uncertainty often accompanies observing loons. Their actions invariably defy simple explanations, leaving me to ponder questions like, “What is the adult loon’s gain from such frequent and loud wailing when no other loon is within earshot?” or “Why would a loon expend energy alarm calling at a harmless muskrat?” It’s rare for a day in the field to pass without my scratching my head at least once over some inexplicable behavior.
Paradoxically, the most effective environment for deciphering animal behavior may not be amidst the animals themselves, but rather in the quiet solitude of an office, meticulously analyzing data. Stripped of distractions and with laser-like focus on the numbers, patterns can emerge that illuminate the answers to central questions.
This very phenomenon occurred for me yesterday. I was engrossed in analyzing territorial intrusion patterns when a surprising finding surfaced: territorial loons intrude more frequently into neighboring territories that contain chicks than do young, non-territorial “floaters” actively seeking to establish a territory. This presented a significant puzzle. Floaters, being young adults on the hunt, are expected to actively search for territories with chicks, using them as indicators of a desirable location. They then aim to displace a resident pair member to seize the territory for themselves. Therefore, one would logically assume that floaters, not established territory owners, would be obsessed with finding, visiting, and competing for territories with chicks. Territory holders, conversely, should prioritize defending their existing domain.
It is important to note here that intrusions into territories with chicks, regardless of who initiates them, are generally ill-advised. As many observers have likely witnessed, territorial loons exhibit heightened aggression towards intruders when chicks are present, making them far more likely to attack. This reality only deepens the mystery. How can we reconcile the tendency of a territory owner, a loon with much to lose, to risk injury by visiting a nearby territory with a seemingly hyper-aggressive owner?
Lacking any immediate alternative explanations, I delved deeper into this curious inclination of territorial loons to seek out neighbors with chicks. Late in the breeding season, territory owners can be categorized into two groups: those with chicks and those without. I investigated whether, as one might intuitively predict, territory owners who had failed to raise chicks—and might thus be seeking to “trade up” to a superior territory—were more prone to intrusion. The data revealed quite the opposite. Territory owners actively rearing chicks were significantly more likely to intrude into neighboring lakes with chicks than were territory owners without chicks.
As it turned out, I uncovered this perplexing pattern late in the day and was unable to fully process it at the moment. However, during an inevitable hour-long period of sleeplessness at 2:32 a.m., the solution dawned on me. While the successful rearing of chicks represents the ultimate objective of an adult loon’s life, chicks also pose a significant hazard. To a floater, the presence of a territory owner’s chicks signifies a high-quality territory. Consequently, chicks raised in one year serve as a guarantee that the owner will face eviction attempts from floaters the following year. It logically follows that owners should employ any and all strategies to prevent floaters from discovering their chicks. A simple tactic of decamping and leaving chicks unattended during the early morning is effective because floaters primarily learn about chicks by observing their conspicuous parents on the water and landing nearby. If you are absent from your territory, a floater is less likely to find your hidden chicks. However, being away from your own territory while simultaneously intruding into your neighbor’s territory offers a dual benefit for a loon with chicks. Your presence near the neighbor’s territory will attract other adults, drawing them away from your own territory, and increase the likelihood that your neighbor’s chicks will be the ones spotted. In essence, neighboring pairs with chicks appear to be engaged in a desperate, reciprocal effort to expose each other’s chicks to floaters as a means of protecting their own territorial claims.
As I pen these words, the grating whine of a circular saw from next door fills the air. Our neighbors have indeed contracted the noisiest and least efficient construction crew west of the Mississippi to renovate their home. The noise, the clutter, the constant truck traffic, and the ceaseless cursing and shouting are, to say the least, tiresome. However, I remain fairly confident that our neighbors are not conspiring with external forces to orchestrate our eviction. In that regard, I suppose we are quite fortunate.
