The Science of Birdwatching

Birdwatching might be a casual activity, a hobby, an avocation, or even a profession (often, perhaps, an obsession) depending on the bird watcher, but there is always a science to it, in at least two ways. First, there is the science of how to do it. In this sense, the term “science” means something vernacular. We as easily say “birdwatching is an art” as we could say “there is a science to it” and here we are using both terms( “art” and “science”) in their older sense where science is how we approach things with our minds, and art is how we approach things with our hands.

Second, birdwatching has a lot of science in it. By this, I mean that when you are watching birds, you are encountering numerous opportunities to consider the science of birds or of that related to birds, evolution, ecology, co-evolution, and so on.

I’m lucky in that I often get to blog from a very excellent bird watching location. Depending on which way I point, I can observe an evergreen treeline on a bluff sporting a bald eagle nest; a protected semi-island where loons nest; a marsh inhabited by transient migrants such as tundra swans or Canada geese and used by local wandering predators such as herons but owned by the blackbirds; open water with minnow filled shallows and some serious depths over which the eagle hunts, on which the loons cruise, and across which terns and gulls soar; a rocky shore ideal for kingfishers; a bit of prairie and mixed woodland with multiple species of woodpecker, warbler, titmouse; a shallow embayment for waders and the occasional wood duck; a thicket with thrushes and their kin; a looming, nearby pine forest with a whole other set of raptors. Right now the loons and their chicks are ten feet off shore in one direction, and I’m 20 feet in the other direction. If I type loudly one of them may look up to see what the sound is.

From this perspective, it is easy to make note of the science connections, and a handful of these connections have come to mind recently.

In this habitat, in my range of sight on a given day, there are a lot of species of little brown bird that eat seeds, and in some cases, they are closely related and very similar to each other, yet there is only one large raptor that eats fish. Gulls and terns fish from the sky, as do osprey, but the presence of a pair of eagles (often with one offspring) using a nest overlooking the 200 acre bay excludes those other birds almost all the time. There are several osprey in the area; I can get in the car and see osprey nests in five minutes, and on a good day find some of the actual osprey in a couple of spots around here, but I’ve only very rarely seen one here in close quarters with the eagle, and then, the osprey do not stay long. I can see terns or gulls in the distance, but rarely do I see them feeding under the eagle’s nest. So, obviously, seeds are abundant and tiny, and as a food source, diverse in the traits that make them easy or hard to find, the degree to which they are palatable, or some other features that allow many individuals across many species to feed on them. But, six to 12 inch fish feeding near the surface, while seemingly abundant, are actually somewhat ephemeral and hard to get. While certain seeds actually “want” certain birds to harvest them (the seeds may benefit through dispersal) the fish are not likely to volunteer to be dragged high into a pine tree and fed to a baby eagle. So, fish eating birds may experience more competition with each other and be more limited in number in a given habitat.

So maybe birding is all about making lists of species you see (I would argue not, but for many this is at least part of it). Well, competition for things like food and nesting sites shapes our list of observed species.

At a larger scale, the very existence of more or fewer species in a region on a continent matters and can be explained by scientific inquiry. Why do we have one species of hummingbird here in Minnesota, but far more in Northern Mexico or southern California? Going back to the fish eating raptors vs. the seed eaters, consider this: We have two species of nuthatch and the chickadee, all pretty closely related, searching for seeds, but only the bald eagle eating fish, under our watchful eyes at the cabin. But at the larger scale, there are many many more species of seed eating “little brown birds” but the list of species of large fish eating raptor, as we look farther afield, grows very slowly. Furthemore, as we expand our territory of investigation, the large fish eating raptor species list grows in large part by adding species that are not really different species, in a sense. Across most of North America, we have the Bald Eagle. When we include Iceland and Greenland we can add the fish eating raptor known as the ern. What is an ern? Well, its a bald eagle with a slightly different distribution of coloration. When we go further east and include Europe, we get the fish eagle. What is a fish eagle? Well, its a bald eagle with slightly different coloration…

What this means is that I can observe the birds eating the seeds off the feeder on the dead birch tree and think about the concept of species radiation and co-evolution of plants and animals; I can observe the eagle soaring over the bay and think about the concept of ring species; and, not yet mentioned but related, I can observe the four species of ‘woodpecker’ that we’ll see or hear on a given day and think about the concept of adaptive convergence (there are ‘woodpeckers’ across the world, doing essentially the same thing, but some of them are not even birds!)

Here is a handful of other questions that arise from basic observation, each leading to a potentially rich investigation of scientific writing on birds:

  • Why do the males and females look so different in some species of birds, but identical in others?
  • Why are seed eaters small and fish eaters big?
  • Why is it that when a pair of hairy woodpeckers comes to the suet on my feeder only the male takes the suet directly, but every other bite he takes, he passes on to the female, who waits inches away?
  • Why does the pair of loons have one or two (or zero) offspring a year and avoid nesting anywhere near any other loons, while the mergansers each have at least a half dozen offspring, and often travel in groups with multiple parents of multiple chicks?
  • How can the presence of eagles, terns, gulls, loons, osprey and kingfishers not affect the walleye fishery in these northern lakes, but the presence of cormorants have such a negative effect on that species of fish?
  • What is that dog doing swimming after a pair of Canada geese and their young? OMG, gotta go… stay tuned, we’ll get to all these topics and more. Eventually.

Comments

  1. #1 Michael Spencer
    June 15, 2009

    Stream of consciousness.

    As I read this piece I wondered why Greg didn’t edit– which is apparently what he does, because most of the time the pieces he writes are nicely constructed.

    But I stayed with it, and appreciate the flow. Sort of like a mind-trip through birding. With impressive species knowledge, too.

    And I never really noticed the paucity of squirrels here after the Red Shouldered Hawk set up a nest in the Black Olive trees. But there you go.