Defend what is yours

An avian allegory

On the Salish Sea, in the Pacific Northwest, the bald eagle is a fairly common bird. There it it, a symbol of America, standing tall atop a fir, or a pine, or a hemlock, surveying the landscape. Looking for lunch with what are, after all, its eagle eyes.

With a wing span greater than the height of most humans, the bald eagle is a large bird, regal and impressive. Since its depiction on the Great Seal of the United States in 1782, it has been iconic. Once abundant across much of North America, populations of bald eagles declined dramatically through the mid 20^th century due to hunting, habitat loss, and exposure to industrial toxins, most famously the insecticide DDT. While we have not rid our world of toxicity—mercury exposure, for instance, remains a huge risk to eagles, and to all wildlife¹—the banning of DDT in 1972 significantly helped predators like bald eagles. By 2007, their numbers had increased so dramatically that they were taken off of the Endangered Species List. The bald eagle is no longer considered a species at risk.

Many times a week I look out on a tiny island in the San Juan archipelago, one of hundreds of islands here that have no humans on them, one that is inhabited mostly by seals, cormorants and gulls. Occasionally an otter can be spotted loping along the low ridge of the island, looking for eggs to steal and to eat, but there are no predators on the island that are full-time residents. The water flows swiftly around the island, posing challenges to boats when the tide is just so, making it difficult to approach. This is a good place to raise a family.

No eagles live on that tiny island, but they do live on much larger San Juan Island, which is nearby. Here the eagles sit atop firs, and pines, and hemlocks, and build nests, and raise their young, and keep their eagle eyes trained on the landscape, looking for lunch.

Gulls, wherever they exist, seem to be plentiful. There are many species of gulls, and even accomplished birders will often despair of distinguishing between some of the species. So on that tiny island I will say only that there are many gulls—hundreds of them. They congregate there, and nest, and lay eggs, and raise their own young there.

To the untrained eye—and mine is untrained, apparently—the gulls pretty much all look alike. But there are many of them, and they care about their children. They are raising them on a small island, in a large group with many watchful eyes, all of which would seem to provide safety against many of life’s risks.

But then, the skill that allows them to populate that island—their flight—is not exclusive to them. Others can fly, too. And some of those others are predators.

The bald eagles sit in wait. They raise their babies elsewhere, but their eagle eyes are often on the tiny island. It is a buffet.

Many times a day, an eagle flies out to the tiny island and riles the gulls. The gulls rise in a cloud, screaming, swirling. The cormorants take flight too, but there are fewer of them, and they don’t say as much. The gulls become enraged. The eagle remains visible—a mostly dark bird in a cloud of white, swooping and diving in amongst the shrieking, frantic gulls.

And then the eagle flies away. Usually, he has nothing to show for it, nothing in his talons². Sometimes, though, he gets something. Last week I witnessed a gruesome spectacle—an eagle flying back towards me, extra legs visible even at a distance, dangling from his grip. It was a juvenile gull. The eagle landed on a tree near me and began pulling downy feathers off his kill. Except the young gull wasn’t dead yet. He lifted his head while I had my binoculars trained on the scene, and I looked away, horrified. The eagle must eat. That does not mean that I want to be witness to pain and a lingering death. Soon, the young gull was dead, the eagle was sated, and the gulls had settled down back on their tiny island. There was nothing more to be done. Their child was lost.

The piece I have left out so far, though, is this: every time that an eagle flies out to the tiny island, and riles the gulls, and sparks a cloud of avian angst before flying off again—every single time, whether he has been successful in stealing a baby or not—when he leaves, he is pursued by a small number of gulls.

Always, regardless of whether the eagle has actually been successful, some gulls pursue that eagle a long way off the island. It’s three gulls, or five, or seven, sometimes a dozen, occasionally just one, but always there is at least someone among the gulls who chases that eagle down, all the way back across the water. Sometimes the gulls flank the eagle in flight, veering in at him menacingly. Sometimes a gull or two will dive bomb the eagle if he lands in a tree.

Gulls are scrappy. They don’t mind getting dirty, and don’t seem to care much about appearances. They are smarter than people tend to give them credit for, and they care deeply for their children.

Every one of us should be as those gulls: They persist. They fight. They do not sit passively by and let their children get destroyed. They see the threat, and they chase it down.

1. Mercury is well established as a neurotoxin, and its environmental prevalence has increased dramatically since pre-industrial times. Here is just one paper on the effect of mercury on bald eagles:  Rutkiewicz et al 2011. Mercury exposure and neurochemical impacts in bald eagles across several Great Lakes states. Ecotoxicology, 20: 1669-1676.

2. The hunting eagle is just as likely to be female as male. Both members of a pair bond take care of the young, and both hunt for their children before they are old enough to source food for themselves. It can be difficult to tell the sexes apart, as their plumage is nearly identical, although as in most raptors, their sexual size dimorphism runs in the opposite direction of what we normally expect: females are larger than males.