Naturespeak A naturalist's view of the world

March 26, 2012

Peck ‘O Dee

Filed under: Uncategorized — wykes @ 12:35 pm

There are quite a few cavity nesting birds in Michigan but few of them, other than woodpeckers and their kin, are equipped to excavate their own places. Wood Ducks are a classic case in point.  They are ducks with duck beaks and not ducks with woodpecker beaks yet they nest in tree holes. Let’s add bluebirds, tree swallows, wrens, kestrels, screech owls and a host of other cavity nesters that are ill-equipped to do woodwork of any kind.  All of the above are entirely dependent upon woodpeckers, rot, gnashing squirrels, and handy humans to produce their hollow homes.

Chickadees are cavity nesters as well, but they do not belong on the previous list of unsuitable carpenters. It is a surprising fact of nature that these tiny dynamos can – and often do – excavate their own nest holes. They have tiny beaks suited for insect grabbing and this appears to be a major evolutionary problem. After-all, wood excavators need powerful chisel-like beaks and re-enforced skulls in order to do their job and stay healthy while doing it. Sending a Chickadee out to do this type of work would be like putting the kicker in as a linebacker against 300 pound opponents. It would all be over in seconds with a flattened kicker, or a smash-faced chickadee, on the field.

Somehow, chickadees seem to manage the impossible. Actually they have found a way to get around the impossible (letting the 300 pounder motor past and tripping him up, you could say). I recently watched a pair of these black and white birds working on a nest cavity and found myself admiring the process (watch short movie here).  Their chosen site was a Hawthorn stub broken off about six feet from the ground.  The snag itself was partially rotten – which is key to this type of Chickadee peck-work. These birds can’t possibly chip away at hard wood but can make do with firm rotten wood.

They were working a spot about 6 inches from the top and had opened up an entrance about 1 inch in diameter by the time I came upon the scene. A brief check of the literature (I don’t like to make everything up!) revealed that most Black-capped Chickadee holes are located within 10 inches of the stub tip. I would assume that this is the place where the wood is punkiest, so it makes sense in that regard. Oddly enough, these birds don’t show any preference for orientation – they place the hole where ever it is easiest to make. Yes, I read that also.

Taking turns, each bird worked the hole for about 5 minutes before yielding to their mate.  The improbable woodpeckers flew down to the hole, braced themselves with a wide stance, and then directed measured blows at the wood. Their action was like that of an ice pick – repetitive but not spastic. Wood chips were mostly tossed to the side and larger chunks were carried off. The act of carrying off one of these larger pieces appeared to be the signal for the other bird to come forward.

In between sessions the birds sat around for a minute, as if shaking off a headache (see above), before starting to seek food.  Once, when one of the birds returned to work, he (or she?) started on the wrong location – the actual end of the stub – and pecked at if for a half-dozen blows before realizing its mistake and dropping down to the correct hole.

I do believe I was witness to a case of Chickadee fatigue in that case. The chickadees stopped soon after this incident and left after 20 minutes of hard work. Their labors resulted in a cavity with the entrance defined and an internal space of only about ¾ of an inch. It was a good start, but only a start. Being so ill-equipped for the job they will spread the labor out over an extended period of time.  This is about the only thing that these animated birds do that can be considered slow. The job will get done but it will be on Chickadee time.

March 19, 2012

House Wars

Filed under: Uncategorized — wykes @ 4:57 pm

Just in case you need another sign of impending spring (other than Peepers, Chorus Frogs, Honeysuckle leaflets, tornado warnings etc.) the Wood Ducks are now seeking out their nest holes. I know this because I happened upon a pair sizing up a tree cavity on the north bank of Swan Creek. When I first spotted these birds they were perched on a dead limb.  They weren’t doing anything per se, except a lot of nervous head-bobbing. There was a hole in the trunk below and they soon directed their attentions to it.

Wood ducks are called such because they nest in tree holes and the hunt for suitable sites takes place as soon as the birds arrive back. Both the male and female birds are involved in the real estate hunt, but it is the female that makes all the decisions (of course).   It is she who was reared in the immediate area and she who will eventually incubate the eggs on her own, so it is her house. The male is there only to provide a little color and the biological contribution that insures that the nest will have eggs.  He has nothing to say in regards to the final choice (which is why he has that perpetual “yes dear, no dear” look).

Her requirements are fairly tight. Wood Ducks seek holes that are at least 4 inches across at the entrance, 6-8 inches in the interior and around 24 inches in depth. Granite countertops are not essential but the doorway should be well off the ground (20 – 40 feet).  A vertically facing entrance is also preferred and that was the only feature of this hole that I could verify.

The hen flipped off the branch, dove for the cavity, and poked her head in for a look.  The drake stood watch on an adjacent limb. His attention was focused on me. His ruby red eyes virtually burned a hole in my direction. Unfortunately, I was not the only potential fly in this domestic scene. A pair of frantic starlings – birds less than a third of his size – were darting back and forth. They had also staked ownership to this cavity and were attempting to keep these house-hunters out. Their actions were ineffective, however, and hen entered the hole without pause and stayed inside for the duration of my observation time– a good sign that she approved the set-up.

There was nothing that the Starlings could really do about it except hope (and pray, if indeed birds do such a thing) that the cavity would prove unacceptable.  Ours is not to feel sorry for them. Starlings, even though small of body, are large on aggression and they are one of the biggest competitors for tree cavities. For those folks who put out Wood duck Boxes, keeping these pesky birds away is a serious challenge. I read about one earnest Wisconsinite who resorted to hanging dead starlings around the entrance as a morbid warning to any new interlopers.  We are not sure how this action affected the Wood Ducks, but it apparently didn’t have any affect on the Starlings what-so-ever (a satisfying idea, though!).

For a few tense moments, the drake stood guard over the west side of the tree and one of the Starlings stood his place on the east side (see above). The Woodie grew increasingly nervous about my presence and finally opted to take a flight down to Swan Creek and keep guard from a safe distance. To his credit, he whined out a few warning calls before departing his loved one. Perhaps he told her to stay in the hole until I went away or informed her of the persistent Starling standing vulture over the hole.  I should say that he “suggested” the above actions because drake Woodies are not the master of their house.

I will keep an eye on this domestic situation and see how it plays out.

 

March 12, 2012

What I Learned in School

Filed under: Uncategorized — wykes @ 9:43 pm

I recently attended a conference at Michigan State University which highlighted the latest and greatest in Great Lakes research. Just to prove that I actually was paying attention, I wanted to bring you a simplified version of one of the papers. This gathering of minds showcased current work in the field of ecology, geo-morphology, chemistry, and something else which I’ve already forgotten. There was a lot of talk about detecting Asian Carp DNA in the Chicago water system and the dynamics of drowned river mouths (bet you didn’t know that rivers could drown, eh?) etc. Not all of it was stimulating, but all was potentially interesting to at least someone in the room at any given time.

The one that really stuck in my gray matter was a paper titled “The Invasive Spiny Water Flea: Disrupting Great Lakes Food Webs through Eating and Scaring Zooplankton Prey – Scott Peacor, Associate Professor, Department of Fisheries and Wildlife, Michigan State University, East Lansing.” I assumed that there was a typo which converted “Scarring” into “Scaring” – after all un-eaten prey are often scarred, right? You know, that torn ear or rump scar resulting from a failed attack. Although it was hard to visualize how this could possibly affect population dynamics (possibly rump scars are a turn-off for reproductive efforts or something?)

Well, this clever title turned out to be exactly as printed. It really was about how a dangerous new invader called the Spiny Water Flea (Bythotrephes longimanus) both consumes and scares the living daylights out of their prey species. These Water Fleas hitch-hiked into our regional waters from central Asia. They are one of the many hundreds of invasives that have wreaked havoc on the ecological systems of our Great Lakes. Unfortunately we already had a host of native water fleas here when this foreigner arrived. Not only are these natives in great danger, they are apparently suffering from PTSD as well.

                                                                                                                                                             Spiny Water Flea

Spiny Fleas look as nasty as they sound. Their dominant feature is an exceedingly long spine – a spine with smaller spines upon it, as a matter of fact (see my drawing above). Although only about half an inch long in total body length, most of this length is given over to this needle-like appendage. With a tail like that, our native fish are less than enthusiastic about eating them. The Spiny Water Flea, however, is very enthusiastic about eating any critter smaller than itself. High on that menu list are plant-eating water fleas called Daphnia. None of these guys are actually “fleas”, by the way, they are members of a crustacean group called the Cladocerans (a late 1960’s folk group that once played with Pete Seeger?)

Scott Peacor specifically studied the effect of Bathotrephes on Daphnia. Without taking any of his thunder, allow me to summarize what he found out. Spiny Water Fleas are visual predators equipped with a single huge eye. They need good light in order to track down their prey and generally keep to the upper waters during the day. Historically, Daphnia are also light-loving creatures that try to spend as much time as possible in those same well-lit upper waters. When the two populations collide, the Spiny Water Fleas tend to get fat and the Daphnia tend to get gone. This was pretty much already known and Peacor re-verified it in his study, but he also wondered what happened to those Daphnia that got away. Did they eventually learn to stay out of the upper waters?

In short, the answer was yes. Not all of them did, but a majority switched their routine so that they spent the daylight hours in the cold dark deeper waters and only returned to the surface at night when their new-found predator can’t see them. So, you could say that the living daylights were literally scared out of the Daphnia. You’d think this was a totally successful anti-predator tactic, but those scared shadow-seeking Daphina failed to thrive and eventually become pin-heads (my words not his). They didn’t reproduce well and their population plummeted. It can be assumed that the same thing is happening in nature. They are damned if they do and if they don’t -or “doubly screwed” if you want to put it in commoner style tongue.

Speaking of simplifying, I was inspired to draw up a cartoon that summarized the whole feeling of Scott’s talk. It is the very one that appears above. I sent my impromptu cartoon to the researcher, Scott Peacor, on the outside chance he might want to tape it on his door or use it for a future PowerPoint. He graciously wrote me back and said that he loved it and will use it. He was especially impressed at how I made the Daphnia looked so scared.

For those who are wondering, I did not draw the cartoon as I watched the conference. I paid full attention, although I must admit to spending an inordinate amount of time mulling over how I could make the starry-eyed Daphnia look scared.

 

March 5, 2012

Keeping a Stiff Upper Tail

Filed under: Uncategorized — wykes @ 8:39 pm

Ruddy Ducks are a prominent winter feature of life on the lower Detroit River. Sizable flocks of these compact little waterfowl raft about the icy waters along with coots, canvasbacks and merganser species.  Most of the North American population winters along the Gulf of Mexico, but a few hardy souls stick out the “r” months here at the glorious mouth of the Straits.

I recently came upon one of these tightly bundled Ruddy flocks in the protected bay formed by Sturgeon Bar Island at Lake Erie Metropark. There was a bright eastern breeze and the birds were resting.  Normally they would be actively diving for wild celery tubers and invertebrates –disappearing and bobbing to the surface like so many fishing bobbers with fish attached! But they were huddled against the cold on this day. Being round little things to begin with, when in the resting pose they look even “rounderer” because they throw their heads over the center of their backs and tuck their beaks under the scapular feathers. Eyes closed, and gently rolling with the waves, they look like fishing bobbers without the fish attached (to stretch an already over-stretched analogy). One writer likened them to Rubber Duckies (dark rubber duckies) and I agree.

Apart from being chunky, the position of their tail is a dead….er, a live… giveaway to their identity (given the future course of this essay perhaps I shouldn’t say the word “dead”). Members of a world group known as the “stiff-tailed ducks,” Ruddys indeed have stiff woodpecker-like tails which they tend to hold upright.  There was a good mix of males and females in this flock. All were in somber winter plumage, but the bright white cheek patches in the group highlighted the male birds. They will take on a bright orange ruddy color (thus the name) and a spectacularly sky blue bill as Spring draws nearer (nearerer?). The mottled females had secondary stripes running across their cheek patches. They will never look any better than they already do (because they already look great – right guys?).

My presence didn’t agitate them too much, but the whole flock moved to the far side of the bay upon spotting me. I had that happen at a party once, but I’m sure it was due to the kid behind me. Some (of the birds) merely adjusted their bobbing course with a few discreet foot maneuvers without even lifting their heads. Others launched into a short running flight along the surface. Ruddys cannot burst from the water like mallards, and other puddle ducks, and have to literally run across the water before take-off. In this case they only ran for about 20 feet in order to put distance between them and the human.

                                                  Look out! It’s those Nazi bird watchers again!!

This whole encounter got me to thinking how this relatively mild interaction would have played out in another part of the world. In Europe, you see, Ruddys are the enemy. Apparently some specimens escaped a captive English collection many years ago and established a wild breeding population in the early 1950’s. The ruddy hellions have spread to the continent and there is now a concerted effort to stop the wild population from spreading. There have been organized culls meant to kill as many as possible. You may wonder how much of a problem these goofy looking little ducks could possibly be. Why would anyone want to stop a Rubber Duckie?

The answer to the above question hinges on the fact that Ruddy Ducks are not native to Europe. They appear to be replacing the native member of the stiff-tailed clan called the White-faced Duck. According to biologists, the White-faces are already an imperiled species due to marsh draining and development. They exist only in isolated pockets from southern Spain, to the Middle East and Russia. Because the Ruddys can mate with and produce viable offspring with White-faced Ducks (they are members of the same genus) they are threatening to dilute the gene pool and possible wipe out the native type. In other words they are out-competing the natives directly and indirectly.

We in North America are used to this alien species scenario as it relates to some invasive European plants and animals on or turf, but give little thought to the reverse scenario of the ugly American in Europe. It’s not the Ruddy Duck’s fault, but it is a great problem- and one without a clean answer better than culling. Unfortunately there are groups that are against all efforts to curb the invasive Ruddys. As usual, these groups display extreme emotion for their reasoning. One of them, called Animal Aide, even goes so far as to claim that this is “killing in the name of blood purity” and that it is intended to “weed out misfits and defectives” just like what “went on in the 1930’s.”  All this is for the benefit of “Bird-watching Bigots”, they say.

Wow, them in some incendiary words. Someone needs to sit in a nice warm tub with a rubber duckie and calm down.

At any rate, I thought it was interesting to glimpse a global view of what appeared to be a purely regional thing. The good news is that Ruddy Ducks here on this side of the pond are loved and appreciated. They belong here in the winter river.  Although they are hunted during the brief fall waterfowl season, Ruddys are not subject to any pressure for most of the year and they are thriving. We bird-watching bigots can enjoy them for what they are.

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