Brown Creeper on Wood Stump

My first encounter with this life form came as a child wandering the banks of the Spring Garden brook near my home in Florham Park. Seeing the bark of an ash tree shimmer like a mirage, I had to seize a double-take before I realized it was even a bird. More curious was the fact it was moving up the base of the tree seemingly without legs – creepers keep these short appendages well hidden under a thick covering of feathers. Knowing the common birds in my neck of the woods like I did made the discovery of a new bird an exhilarating experience; to me it was like exploring a new continent for the first time. Watching this bird glean the bark clean of indistinguishable insect minutia with a bill shaped like some sort of a recurved surgical instrument was absolutely fascinating. The bird’s short bursts of flight from tree base to tree base, a common foraging tactic, add to the bird’s arsenal of deception. Even the bird’s vocalization, a frail tumbling “seesooysooysoo” is another guise, a cryptic hint of its passing. A debt of gratitude I owe to this bird which helped me hone my naturalist skills early on. It is the brown creepers allusive nature that taught me never to overlook an inconspicuous movement or nuance amongst the backdrop of the forests skin.

I am convinced this creeper has taken up residence in the Great Swamp for every aspect of its life history. The birds breeding biology dictates a propensity for old growth coniferous swamps and woodlands that are dominated by deadwood. This habitat description mirrors much of the interior deadwood sections of our refuge. The fact that I see adult creeper’s in the swamp foraging the base of trees in late spring and summer are a sure sign that this species breeds here. One of my goals this spring is to locate and document one of the most mesmerizing aspects of this bird’s secret life - its nest placement and design.

Brown Creeper on Tree Limb

Brown creepers conceal their remarkable nest structure behind loose tree bark, in the crevices of trees, or where ivy or accumulated debris offers cover. This hammock –like structure is usually placed low to the ground never to exceed 15 feet. The nest itself is a loose cup of twigs, rootlets, wood fibers and moss, often lined with feathers, fine bark and even wool when it can be found – sounds cozy to me.

A bird voyeur’s best shot of catching a glimpse of a creeper is in winter. At this time you might see the ghost-bird hanging out amongst communal groups of mixed species. The brown creeper is often sighted with its genetically connected brethren - nuthatches’, wrens, titmice and chickadees – who help secure them in the habitats in which they forage. This behavior is termed intraspecific flocking, and serves all the species in the flock well by augmenting the affects of visual acuity. It is better to have many eyes to the sky when the leaves have dropped in order to keep a close lookout for airborne predators like the ever present woodland accipiter’s - goshawk, copper, and sharp-shined hawks.

Global bird declines worldwide are garnishing the headlines of ecological journals these days so it may be refreshing to know that the brown creeper’s population is on the rise. It seems to be taking advantage of newly created and favorable habitats left in the wake of introduced pestilence. The mortality of trees due to gypsy-moth invasion, and mortality of American elms due to Dutch elm disease have caused an expansion of the creepers range in Mid-Atlantic States, Midwest, and California. You could say that one bird’s dead tree is another ones castle.

To this end the Great Swamp Wildlife Refuge staff has done a great job throughout the management area to increase biodiversity by manipulating habitat types. This can have a measurable effect on the more obvious species that we encounter, for example, great blue herons and woodcock. For the more esoteric denizens of the swamp like our creeper, the wildlife managers have intentionally left many dead trees untouched throughout the management area, this helps maintain a more complete ecological functioning. Dead timber benefits entire guilds of animals that gravitate to these microsites in order to help nurture their biological needs. People who own large tracts of land within the Great Swamp Watershed would be wise to learn from this technique and allow trees to completely fulfill their life cycle; this in turn will help ensure the survival of the many species that engage them.

When it is my privilege to encounter this bird upon the wood I will always stop and watch, as if it were my first time, for the honor to be in its presence is all mine. I think the naturalists of old were much more in tune with nature’s pulse compared with those of modern day. Listen to this beautiful narrative by Winsor Marrett Tyler in 1948 as he describes the brown creeper’s movement through a forest:

"The brown creeper, as he hitches along the bole of a tree, looks like a fragment of detached bark that is defying the laws of gravitation by moving upward over the trunk, and as he flies off to another tree he resembles a little dry leaf blown about by the wind"

- man that’s good!