Naturespeak A naturalist's view of the world

December 10, 2007

Quoth the Night Raven: “Maybe”

Filed under: Uncategorized — wykes @ 8:15 pm

 December may seem like an unusual time to talk about a summer bird like the Black-crowned Night Heron. The sight of one of these sulking water birds silhouetted against an evening sky, while perched atop a dockside post, is a common warm weather sight.  True to their name, they are creatures of the post sunset world. Often their belch-like squawk is the only thing that betrays their otherwise shadowy presence.   It is worth noting that their scientific name Nycticorax nycticorax, literally means “Night Raven” (something that is apparently worth saying saying twice twice).

  Since most of them migrate to the southern U.S. or Central America in the fall, the question still remains as to why I bring them up in a winter context. The simple answer is that not all of them migrate south.  Every year, a gang of 15-20 hearty Night Herons elect to stay all winter in the sleepy little burg of Gibraltar, MI.  Presently, there are about 17 of these birds roosting in the canal-side trees visible along Pointe Dr. & Stoflet Dr. in that riverside village. At this time of year, the aerial Heron herd is easily seen – something nearly impossible to do when the trees are fully clothed.

 From a distance, you’ll see a collection of brooding shapes – like so many, well, disgruntled ravens – scattered among the branches.  The shapes are about two feet long with a sizable wingspan measuring just under four feet. Long legs testify to their wading habits and long beaks exhibit the tools of a fish eating bird. As herons, they have fairly long necks as well, but choose to hide them between hunched shoulders while perching. Gibraltar resident Ron DeWalt has been living with these wintering birds for some time now. He is one of the homeowners whose yard trees serve as daily perches. Ron was able to take a few terrific pictures of some of the birds roosting in his yard trees. His images were taken a month ago just before the last Silver Maple leaves were shed. The first picture is of an immature bird (brown with white speckles) and the second is of a mature individual (white chest, black crown and gray back).

  Black-crowns don’t become black crowned until their third year out of the egg.  While the younger birds have a great look, the stark adult coloring is classic. Mature birds have a set of long feathers – like long thin white ponytails – trailing from the back of their heads. When landing, or taking off, this feature becomes evident.  “They look kinda like a Bird of Paradise,” says Ron, “with those long feathers coming out.”

  So, what is it that prompts a normally migratory bird into a non-migratory lifestyle?  I can’t tell you what goes on under those little black crowns, but it comes down to a question of gas.  As long as the food reserves are there in the form of abundant shiners and minnows and the water remains open, the birds can re-fuel their tanks and live a relatively good life.  Cold temperatures have very little to do with anything. Most large bodied birds can tolerate cold weather.  They are possessed of nice down filled vests after all.  Migration is a dangerous thing to do, so in this case these home bodies are simply playing the odds. 

  It’s worth noting that other herons, such as the Great Blue, do the same thing.  Often 50 or more of these birds over winter on the shores of the Detroit River.  The larger herons can’t stand people, however, so they don’t roost near houses and generally stay out of camera range.

  If Dame Nature should decide to inflict an extremely harsh winter upon us this year, there’s a distinct chance that the brave black-capped mini-herons might be forced to re-think their tactic and move south.  They all run the risk of death due to over exposure and starvation if temperatures plunge into sub zero and all available water freezes solid (thus closing access to the gas stations). As it is, the herons have not been put to the task and they continue each year as snowbirds.

  Just across the creek from where the herons are roosting there is another bird “pushing the winter envelope,” so to speak.  A female Scarlet Tanager has opted, for whatever reason, to remain at Lake Erie Metropark this winter. She is possibly the only one of her kind in the entire northern hemisphere.  All others of her ilk have migrated to South America. It is a fact of nature that tanagers in general are basically a tropical species. Sure, they visit the northern climes to enjoy the brief summer, but they quickly return to their tropical homeland in the fall.  In order to re-enforce this rain forest origin one only need look at the name “tanager” to find that it stems from a mispronunciation of the “tangaras” designation given them by the Tupi Indians of the Amazon.

  The last time I saw the misplaced tanager, she was plucking a frozen grape from a meager cluster hanging on a wild vine. She looked good and appeared to be doing well so far. Unfortunately, the cards in this case are stacked against her.  As a small bodied bird scarfing out a living in an unfamiliar time setting, she will be fighting an uphill battle. 

  I’m fairly confident that the Black-crowned Night Herons would publically root for the brave little tanager’s cause, but privately might express a harsher take.  When asked about her odds in this affair they would shrug their shoulders and give a one word reply. Quoth the Night Raven: “Maybe.”

No Comments »

No comments yet.

RSS feed for comments on this post. TrackBack URL

Leave a comment

Powered by WordPress