Research to Watch: How do humans affect wildlife?

Calvin of Bill Watterson’s famous comic has a few iconic lines, such as “It’s a magical world, Hobbes ol’ buddy…Let’s go exploring!” This is exactly how I picture scientific research, especially in the field of ecology.  Our home is so immense, so complex, and there’s so much to discover!  The more we know, the more we marvel at God’s handiwork.

Madison County, Montana. Shared under the Creative Commons license.

A recent study from the Wildlife Conservation Society compared how songbirds in two very different habitats, the Adirondack forest region of New York and the Greater Yellowstone Ecosystem in Montana, respond to human development going on around them.  Human development of a rural area means that the habitat will be changed structurally–a house replaces trees, et cetera.

The scientists asked the question, “do songbirds in different habitats respond in similar or different ways to rural development?”  In order to answer this question, the researchers had to understand what influences songbird behavior, so they classified the birds according to how they make a living: some nest on the ground, some live in human residential spaces, some need large tracts of undisturbed land, some migrate in the winter, and some use one specific habitat quality and are only found in areas with this quality (for instance, holes in dead trees).  The following five categories are the ones used by the research team:

  • “edge specialists” – birds that favor forest/field ecotones and often thrive in residential areas;
  • “low-nesters” – those nesting at or near ground level;
  • “area sensitive species” – species that respond negatively to decreasing habitat patch size;
  • “Neotropical migrants” – birds that breed in North America but migrate to Central or South America during the non-breeding season and,
  • “microhabitat specialists” – species dependent on resources likely to be variable or patchily distributed such as nesting cavities.

Now, the scientists looked at their two habitat study areas and probably thought to themselves,

Adirondack forest. Shared under the Creative Commons license.

“these are very different habitats.  One is highly variable, changing from forest to prairie and river, all across a varying altitude; the other is forested and pretty uniform.  Given these habitat differences, it would make sense to me that the songbirds would react differently depending on which of the two habitats they live in when people come and build a couple houses.  In fact, I bet that the songbirds will show less change in the Yellowstone habitat because it’s so diverse, and more change in the Adirondacks.”


This is called a hypothesis, and this is what the researchers tested.

(Imagine both parcels of land before they are developed at all, with the five groupings of birds.  Now imagine a neighborhood shows up.  What do you think would happen in each location, and within each bird group? Do you agree with the scientists’ hypothesis?)


Their results surprised them.

Their study found that in both habitats, the “low nesters”, “area sensitive species,” and “neotropical migrants” responded in similar ways: they moved out.  For instance, in both the Yellowstone and Adirondack habitats, “low nesters’” relative abundance changed 70-100%!  Of the five groups, only the “edge specialists” increased in abundance with the development.

They expected to find that bird responses would be different between the two habitats, but instead they found the birds responding in remarkably similar ways.  Essentially, this means something else besides habitat structural change might be causing the birds to respond in they ways they do.  It could be human behavior or disturbance that affects songbirds more than habitat change.

What sort of human disturbance could be affecting birds?  We already know from other studies that nighttime lighting and noise affects birds and mammals.  Even our pets and vehicles play a role in altering the environment, affecting wildlife communities.  Of course, it’s hard to say which factors are the most important to change in order to maintain healthy wildlife populations.  Research is underway right now to explore further the role of human behavior on bird community responses.

Streetlights in Virginia. Shared under the Creative Commons license.

Once we understand better our effects on wildlife, we can use that information to better protect the birds and mammals and other creatures that we share this planet with.  People are part of the ecosystem, and when we see how our role affects other members of the system, further studies can inform landowners how they can minimize their negative impact on God’s creation.

 Briefly, here are a few changes we know are important to make right now to benefit God’s wildlife:

  1. Keep your pet cats indoors at all times.  Collectively, they kill billions of birds in the United States alone annually.
  2. Leave dead trees standing, as they provide habitat and food for many species.
  3. Incorporate native plants in your landscaping, which attract native insects, an important food source for many birds.


For the original paper:

“Identifying Common Patterns in Diverse Systems: Effects of Exurban Development on Birds of the Adirondacks and the Greater Yellowstone Ecosystem,” appears currently online in the journal, Environmental Management.