Knock, Knock...who's there?

Tap, tap, tap, tok, tok, tok, tap, tok, tap, tok, tok…

I stood on a small rise at the base of five of the finest bird environments that the Milwaukee County (Swan Boulevard) Water Detention area had to offer; listening. Technically there are eight oak trees on this spot, but five are singles and one is a tri-oak of sorts. I often visit here to collect my thoughts, feel the breeze on my neck and the fading orange, evening sun on my face. It’s peaceful and wild; the last tiny remaining vestige of the glorious forest that stood here prior to the county’s need for a large open area in which to collect enormous amounts of suburban storm run-off. These gnarled old oaks were thankfully left standing by some thoughtful planner and have provided so very many species of birds with a place to rest, nest, and dine.

The “tap-er-tok-er” turned out to be a White-breasted nuthatch (Sitta carolinensis) clinging upside-down to the side of one of the oaks, pounding its long specialized bill (nearly as big as its own head) into and around a small opening nestled in amongst the thick gray folds of tree bark. I zoomed in and stood there watching the small black and white bird, laboriously working on something obviously important to it. “Nest?” my mind asked. Nuthatches are predominantly cavity nesters, however that seemed unlikely. “Bugs” was my next guess as I watched it repeatedly banging away in the same area of bark. WBN’s are nearly six inches long and do not migrate, but rather inhabit a territory of up to .2 square kilometers, defending it with a series of calls and aggressive maneuvers. Preferring older more mature forests (particularly oaks), they will leave their areas only if food becomes scarce, particularly when their 100% summer food source (insects) forces them to switch to seeds in winter. This fellow was hell-bent to find something in that opening, so it kept pecking away as I watched; wishing I had a camera.

My own vigil paid off as I watched the bill of the WBN pry out an orange and black Banded Wooly Bear (Isabella moth caterpillar). The bug fell to the ground with the bird immediately flying down to reclaim its prize. The banded Woolly Bear larva emerges from the egg in the fall and overwinters in its caterpillar form, when it literally freezes solid. First its heart stops beating, then its gut freezes, then its blood, followed by the rest of the body. It survives being frozen by producing a cryoprotectant in its tissues. In the spring it thaws out and emerges to pupate. This one was thawing and unfortunately attracting the attention of the WBN in the process. The bird snatched the bug from the grass below the oak and flew to a nearly horizontal limb, also within my binoculared eyesight. The deep grooves in the bark provided a “vise” of sorts in which to contain the caterpillar as the nuthatch pounded, twisted its bill, flipped, and pecked the insect into smaller and smaller bill-sized, edible specks. Once the bird moved the bug to another similar horizontal neighboring limb and worked on it for a full 10 minutes more before I moved on to allow it an unobserved finish to its meal. “Cool.” I proclaimed as I walked away to see what else might amaze me.

It only took a few more steps when a movement caught my eye in the direction of a group of last year’s burdock plants. A tiny bird had landed on a stalk quite near a cluster of the dreaded Velcro-modeled, “burrs.” Common Burdock is a plant with large flat leaves that look like rhubarb. The flowers resemble thistles and when they die the seeds forma round ball that attaches by its barbed Velcro-like hooks to clothing, dogs, anything it touches. Common Burdock grows 1 - 1.5 meters tall or more. Each stalk is loaded with round balls of seeds surrounded by hooks. After a walk through a waste or brushy place, the odds are that you have had these burs clinging to your clothing. Viewing the bird in my binoculars; it turned out to be an American Goldfinch male. The bird had just begun to “yellow-up” as larger patches were visible. It proceeded to pick at the burrs with its beak; pulling out seeds and eating them.

I personally had never before seen this activity (birds enjoying the burdock as a food source), so I watched for quite a while; never once did the goldfinch come close to getting “stuck” as the many burdock alarmists would have you believe. Granted, kinglets (both Ruby-crowned and Golden-crowned) are the ones cited as having the greatest difficulty with entrapment, however could it just be possible that fervent eradicators merely use that oft-recounted anecdote as heart-wrenching rationale for its complete and total removal from existence? People who often preach about non-native invasive species of all sorts will tell you, “Burdock is not a native North American plant, but was introduced from Europe,” as their be-all, end-all rationale for complete eradication. I might argue that most human beings currently in the United States fit the same definition. I won’t judge others conviction at this point; however watching the goldfinch enjoy its early spring meal caused me to question the current (urban legend-like), zero-tolerance, removal mantra.  There's also a little evolutionary theory from a man named Herbert Spencer (after reading some Darwin) who coined the phrase, "survival of the fittest."  While experts will argue that the phrase is incorrectly interpreted; dumb things usually die first.

I crunched down the slope to enjoy the Song sparrows, male Red-winged blackbirds, and a single (early) Palm warbler as it foraged in the brown grass of last year…life is good.



Bird list:

1. White-breasted nuthatch
2. American Robin
3. Northern Cardinal
4. Palm Warbler - FOY
5. Song Sparrow
6. Tree Sparrow
7. Red-winged blackbird
8. American crow
9. Mallard
10. Killdeer
11. Common grackle
12. European starling
13. Chipping sparrow
14. Canada Goose
15. Ring-billed gull
16. Herring gull
17. Black-capped chickadee
18. Mourning dove
19. Pigeon
20. House sparrow
21. House finch
22. Red-bellied woodpecker
23. Downy woodpecker