Thursday, July 30, 2015

My Year of Observation

My neighborhood.

--is what Henry David Thoreau wrote in his journal in July 1852, as he sought to pay special attention to the animals and plants he encountered.  This from a man who observed continually in his own community, once wryly observing, “I have traveled a good deal in Concord.”  For much longer than a year he meticulously recorded the flowering and leafing-out of hundreds of flowers, shrubs and trees.  (So meticulously, that his recorded observations have been profitably mined for comparison with modern data, documenting the changing climate.)

In the year or so since I began to track the phenology of some of my local trees, I have also been more careful, patient, and observant.  Lately I have mulled over how different this year feels from last year, and the reasons for it.  Last year I was often confused, often waiting for things that did not occur, and simply ignorant of basic facts—an amazing thing, considering how much information is just a few clicks away. 

Red maple in bloom last year.  

 Sugar maple April 28 & May 3 of last year.

 Once the leaves have expanded, samaras seem to disappear.
Only the occasional fallen twig or aborted samara shows they're still up there somewhere.

Last year I watched the red maples flower, leaf out, set fruit, and scatter its offspring in a neat sequence that you could almost set your calendar by.  Looking at sugar maples a bit later, I watched them flower and leaf out, then wondered why I didn’t see samaras.  Perhaps these were male trees.  When samaras began to appear on the ground a few at a time, I considered that the sugar maple, which is a northern tree, might be too near its ecological limits to reproduce efficiently. 

Same sugar maple branch a year later.
Samaras ripening on July 23.

This year I have learned to find samaras buried among the leaves if branches are low enough and you look for the right angle to show them up.  And this year there are a lot of samaras up there.  I also learned that sugar maple, unlike red maple, has male and female flowers on the same tree.

Last year I didn’t discover silver maple until the spring was well underway, and did not know when it flowered.  Now I know that it is among the first trees to do so; I watched it flower this year, along with quaking aspen, which also wasn’t on my radar screen last year.

Silver maple began to bloom on April 6th.
I discovered ash-leaved maple, already with well-grown samaras, on May 23rd.

This year I am watching two maple species I didn’t even know about last year: the weedy native Ash-leaved Maple, and the alien Sycamore Maple.  It was well along in the growing season before I discovered them, and next year I will be able to put them in their place when I see them flower.  I also have more individuals of each species to keep an informal eye on.

I saw sycamore maple only on June 5th.  Besides having toothed and more
strongly-ribbed leaves than Norway maple, this alien has samaras are often in threes.

Ashes had me even more confused.  I have never seen any samaras under the stately white ash in my back yard.  Yet there are several white ash saplings in the woods only a few yards away.  Last year I watched carefully when it began to spring, but could never say what happened to those flowers, or even their gender.  Sure they were up there somewhere, I waited in vain in fall for samaras to appear on the ground; they never did. 

This year I discovered a couple of ashes at the high school with branches low enough to look at closely.  These were male trees.  Early in the summer I happened upon a prolific female ash directly across the street from other trees I was observing.  Although the branches are a bit higher, they’re well within reach of my camera, and show me what I might expect from a healthy female.  I found a couple more recently, but these new females are in poor health—another issue to watch.  
My beloved white ash right now;
The female ash a few blocks away with some of her many, many babies.

Last year I watched male catkins erupt on all the oaks, but had no idea what the female flowers looked like, and never saw any acorns on the branches I was watching.  Again, I wondered why, and speculated that city living wasn’t good for oaks. 

This year nearly every oak in the neighborhood is laden with acorns.  Although this is a real change, it’s also true that I’ve learned how to look for them: acorns are nearly invisible when branches are viewed from the side, but from the ends and especially from beneath they can be spotted.  Lighting is also important. 

 These black and white oaks have low enough branches
 to track the growth of acorns easily.

More commonly, I take zoom photos of higher branches,
and then enlarge them further (red oak).

Oaks of the red oak group (those with bristle-tipped leaves, among other distinguishing features) have been transforming before my eyes this year.  Last year I believed that most of these oaks were hybrids among several species, and that true examples of pure red, black and scarlet oaks were rare in the neighborhood.  I thought so because I found scarlet oak leaves on trees with black oak buds, and so on.  This year I learned that hybrids are relatively rare among oaks, but their features can vary quite a bit.  Now I believe my neighborhood oaks are probably all card-carrying members of their respective species, but I still lack the confidence to assign them to those species.  In particular, the neighborhood may be full of black oaks and empty of scarlet, or the reverse—I simply don’t know.  The crop of acorns coming up may help distinguish them. 

Those acorns have been another part of my education.  Oaks of the red group differ from those of the white oak group in having acorns that take two seasons to mature.  Now I have seen this development up close: the female flowers are very small and borne in pairs in the axils of the leaves, looking at first much like buds.  Meanwhile, fruit begun last year is developing and growing on last year’s twigs, looking more and more acorn-like as the summer progresses.

One further change.  I began by observing a one-mile route, and made the bulk of my observations on trees I was watching for Nature's Notebook.  Branching out, I discovered other species and--just as important--found new individuals of trees I thought locally rare.  I began observing just two silver maples, one ash-leaved maple, and one shagbark hickory.  Now I have three or four silver maples to compare, three stands of ash-leaved maple spread over a mile, and several shagbark hickories in neighborhoods almost a mile apart, and several fertile female white ash trees among the dozen white ashes I know.  I now walk three different routes with the dogs, each taking us in a different direction.  By walking them in order, I ensure that most plants get a good look about every three days.

Overall, I know so much more than I did a year ago, and with that knowledge comes a certain confidence.

Thursday, July 23, 2015

Paying attention, again

No, it was not a good day for wasp-watching at Houghton's Pond baseball field #2.  Conscientious groundskeepers had dragged some sort of machinery over the ball fields, burying almost a hundred mama wasps in their burrows, and earning their undying enmity.*  Most mamas had not finished digging out.  I found only two beetles on the ground, and caught only two wasps carrying beetles in the air--and this in well over two hours' work. 

I have now spent over ten hours total divided between contemplating little holes in the ground, and dancing madly, lunging and swinging at flying critters.  (Actually, chasing wasps is time wasted: realizing they're danger, they begin evasive maneuvers.)

Besides doing a public service (and working on my tan lines), and without necessarily meaning to, I've become a bit of a knowledgeable observer of bare-ground ecology in general and these wasps in particular.  

 Called "velvet ants" because of their shape and covering of soft hairs, 
the many species of these wasps sport a variety of bright colors.  
In general, it's best to avoid animals with bright colors: they warn of venom.

Velvet ants are now old acquaintances.  These brightly colored insects running about the dusty ground aren't ants at all, but a very large family of wingless wasps masquerading as ants.  They aren't interested in me, and I leave them alone: the sting has earned some the nickname "cow killer."  (Best not to sit down on bare ground.)

Several other flying, running and hopping insects have caught my notice as typical residents of this habitat, though I mainly register them as "non-target species," as I go about my job. 

 You've heard of the Right Whale, so called because it was the right one for whalers to chase?
Well, this is the Wrong Wasp.  Notice the burrow is angled, and the hill asymmetrical.  (Cerceris fumipennis makes neat, vertical round holes surrounded by symmetrical hills.)

I've noticed the wasps vary widely in size, with the largest the equal of big hornets.  Why?  These beetles are, I believe, all about the same age.  The few wasps I've netted carrying beetles seem to show that big wasps catch big beetles, while smaller wasps catch smaller beetles.  (The eleven beetles I discovered abandoned outside a burrow on Monday were remarkable for their uniform size.)

I'm guessing these beetles were all captured by a rather small wasp.

Finally, the wasps themselves, Cerceris fumipennis aka "smoky-winged beetle bandits" are a trip.  Especially today.  They apparently navigate to their burrows at least partly by sight.  Today, emerging into a changed landscape after the groundskeepers left, the wasps spent a lot of time flying around their burrows, trying to fix their location without familiar landmarks.  They reminded me of my own maneuvers when I cannot remember where in the crowded mall lot I left my car.

 "I could have sworn I left the front door open!"

 "Yikes!  That wasn't MY front door at all!"

 "--and don't come back!"

Sometimes they get their navigation wrong.  I saw one wasp land on a burrow blocked by newly-excavated dirt.  Since these wasps push the dirt out from beneath, the blockage could only conceal a wasp already in that burrow.  The new wasp dug industriously through the blockage and entered the burrow.  Inside of three seconds she had re-emerged and taken wing, and then circled confusedly for a second or two before flying off to check her luck elsewhere.  The earlier inhabitant emerged partway, looking thoroughly put out.

The second time this happened, in a different place with other participants, I thought to make a video.  In this case, the digging wasp worked furiously without finding the hole she was looking for.  She would take a break, fly around a bit, and resume work.  I don't know what happened to her; I don't know if a wasp can start over and make a new burrow so late in the season. 

You can feel her frustration at not being able to open what she has identified as her burrow.  
She practically does head-stands trying to force an entrance, 
and has to take a flight break once in awhile.

Twice more I saw wasps try to enter burrows already occupied; I'd never seen the like before.  One of the disappointed wasps then flew down and crawled under my shoe.  When I carefully lifted it up, leaving the wasp in bright sunlight, she headed under my other shoe.  When that didn't work she crawled briefly into the shadow of a blade of grass.  From this I gather that they are drawn to dark places; and in fact the burrows are very visible when an overhead sun lights the ground and the holes stand out by contrast.

I put on my evolutionist thinking cap while leaving the field in late afternoon.

What is the "adaptive landscape" for this animal?  The wasp must dig out in spring, mate, make and maintain a burrow to protect its young, locate beetles, capture and paralyze them, lay an egg on each, and do all this while dealing with potential predators, groundskeepers, and nut-cases wielding nets.  The wasp that does any of these more successfully than its neighbors will have more successful offspring and be favored in the "struggle for existence."

Wasp size probably has big consequences.  A big wasp catches big beetles, and has offspring that have a bigger food supply, and those young probably grow into large adults.  (The adults eat, but only flower nectar, which has no protein.)  I wonder whether bigger wasps lay more eggs than smaller ones?  I wonder what the mortality rate among the young is by size class?  I wonder how small a wasp is too small to catch beetles that are big enough so wasp young don't starve?

I wonder how the peculiar hunting method of the wasp developed.  The wasp stings the beetle in  a particular place: a leg joint where the beetle's shell is thin--a chink in their  beetley armor.  I can imagine an ancestral wasp population that tried to sting beetles in a variety of places, but those that passed down in their genes a tendency to hit that exact spot had more success, produced more offspring, and spread those genes more widely in the population over time.

*Kidding about this last part.  These wasps are not vindictive: I have captured dozens, and when I release them they just go about their business, though with slightly dazed expressions. 

Monday, July 20, 2015

Wasp watcher: Finally, success

Long and effort under a scorching sun yielded me a few more beetles at another site yesterday.  [See previous two posts for context]  But with a "quota" of fifty beetles to collect at each of three different sites before mid-August, I was getting pretty bummed.  If our organizers thought that was doable, then I must be one spectacularly incompetent Wasp Watcher!  I was especially put out that I couldn't see any discarded beetles on the ground.  (The entomologist called the wasps "messy eaters," and assured us we would get most of our beetles by cleaning up after them.)

A wasp stares back at me from inside her burrow.  the three spots on her face are additional confirmation of her identity: Cerceris fumipennis.

Today I decided to visit my third site: the baseball fields by Houghton's Pond.  The afternoon began as it often has with me trudging around the field marking the modest number of scattered burrows.  After I'd located most of these on the first field, I decided to wander over to the other, hoping for better.  For once I wasn't disappointed: I counted over eighty burrows before I'd finished.  Early in the count, I spotted something unusual; kneeling, I could hardly believe my eyes--a single burrow littered with discarded beetles!  I collected twelve in just a few minutes.  Their appearance was unmistakable: if they had been present in my other sites I could not have missed them.  I went on at that field to pick up two more from the ground, and netted four in the air.

At the rate the wasp going, she'll never get her larder stocked.  No matter how much of a survivor she is, if she doesn't reproduce successfully, her genes are pruned from the tree of life just as if she'd never hatched at all.  Such is the harsh reality of natural selection.

Though my luck didn't hold at other sites that day, I was now pretty confident I knew my business; if I didn't find beetles at a site, there probably weren't many there to find.

I'll worry no further about quotas.  I'll do my job and let whatever happens happen.

Saturday, July 18, 2015

Wasp Watcher: First Real Try

Wanted: emerald ash borer, or any of several invasive oak borers.
Place: West Middle School.  
Date: July 17th   
Time: 2:00-4:30pm   
Number of wasp colonies: 25-31  (Six had no fresh soil around them)
Haul: one (count 'em ONE beetle, netted along with wasp.  (None found on ground.)

Lessons: It doesn't pay to go early--wasps were still digging out when I arrived, since holes would appear where I had already searched.  Also, the half-dozen wasps I netted were all in the final hour, so they weren't flying much earlier.

I learned in training that netting wasps was fun, and added to the total of beetles collected.  (As well as being more certain, since the beetles wasps carried were certain to be the right sort.)  But most of the beetles would be found on the ground.  This was because wasps were sloppy, or dropped those they decided were not good food for their kids.  (One possible explanation: a beetle dies after capture instead of being merely paralyzed.  The babies like their meat still breathing.)  I seem unable to find beetles on the ground.  (Either that, or my wasps are much more efficient than the run-of-the-mill.  Since these are West Middle School Wasps [rah!] that is probably the explanation.)

 My insect net arrived today from Amazon, so I got going.

 One of my employees: the wasp Cerceris fumipennis aka "smoky-winged beetle bandit".
Note the band on the abdomen, and especially the three yellow spots on the face.

The afternoon wasn't a total loss, since a pair of unfamiliar birds
came to sit on a fence, sing and have their portraits taken.
Eastern kingbird, maybe? but this bird has a yellow beak.

Last night I found an email from our handler, who casually noted that another worker had closed out his site by collecting eighteen beetles yesterday.  18!!!  I am a real slacker!  (Our total target per site is 50; after we collect that many, we leave the females wasps alone to reproduce in peace.)   To make matters worse, the one beetle I netted may have simply been in the way of my net, since it was quite lively--not paralyzed by the wasp's sting.  Well, there's always tomorrow.

Thursday, July 16, 2015

Jeff Michals-Brown: Wasp Watcher

Well-equipped Wasp Watcher on a baseball field:
Bag with water and sunscreen--CHECK
 Vial of alcohol (for preserving beetles, mind you)--CHECK
Indiana Jones hat set at a fashionably rakish angle--CHECK

I am now an officially trained Wasp Watcher.  I will spend a few hours each day or so from now to early August monitoring colonies of Cerceris fumipennis wasps in their preferred habitat: nearly bare, hard-packed sandy soil like that around a slightly down-at-the-heels baseball diamond. 

Why, you ask, would I want to stand in the hot sun for hours at a time watching wasps?  It's part of a nifty trick called biosurveillance.  The wasps are, in fact, working for us; and I am watching to see what beetles they bring home.

 Cerceris burrows look like ant hills with over-sized openings.
Soil is piled up evenly all around, and the hole is big enough to put a pencil in.

"Smoky-winged beetle bandit," wasp is the common name tentatively given to Cerceris fumipennis.  The yellowish band around the base of the abdomen is easy to spot, but not diagnostic: Cerceris fumipennis has look-alike relatives.  The real McCoy also has three yellow spots on its face.

You can be sure you have the right wasp when you see it enter or leave its burrow!
NOTE: the wasps are on the small side, and don't seem able to sting humans.

The "wrong" wasp, digging the "wrong" hole: 
notice the soil is almost all to one side.

It started for me a year ago when the majestic white ash in my back yard took sick.  Leaves yellowed and fell all summer and fall until it was bald before its time.  So I did what anyone frantic with worry would do: I turned to Google.  I quickly turned up the Mother of all ash killers: the Emerald Ash Borer.  The EAB is an invasive alien beetle from Asia which probably came into this country accidentally--like so many alien invasives before it.  It was discovered in Michigan and nearby Canada in 2002, after being imported in packing materials, probably years before.  The beetle has spread rapidly, reaching a point north of Boston just last year.  The ash trees that evolved with the EAB in Asia can usually survive an infestation, but all ash trees on this continent die.  The adult beetle eats ash leaves, causing little damage, but the beetle larva bores under the bark; the damage to the bark usually girdles the tree and kills it in a matter of months   I watched my tree anxiously for signs of beetle infestation.  The good news: my tree didn't have them; it was sick with something less serious.  The bad news: the Emerald Ash Borer was spreading unchecked, and was expected to eventually eliminate ash trees wherever in North America they were.  The EAB was recently ranked the most destructive insect in the country.  My tree, currently in the bloom of health, is doomed--so is yours.

Sadly, we have aided the Emerald Ash Borer in its spread.  On their own they might migrate a few miles in the space of a year; at that rate, we should have had many years to deal with the problem.  However, if the larvae happen to burrow into a trunk that later becomes firewood, and someone transports that firewood to another place, the beetle spreads astronomically faster.

What does the wasp, Cerceris fumipennis, have to do with this?  The wasp is a good card-carrying native, and harmless to humans.  But it is a fierce predator to certain types of beetles: those wood-borers of the family Buprestidae, called Jewel Beetles.  It stings the beetles, and carries the paralyzed insects back to its burrow to lay its eggs on.  The wasp is good at catching beetles, and Wasp Watchers are good at catching wasps.  In effect, the wasps are sampling the local beetle population, and doing it far more effectively than we can.  We need only confiscate some of the beetles to find out who's out there.  The collected beetles go on to experts who will identify them. In short, we are putting wasps to work finding us invasive wood-boring beetles.

Although the EAB isn't hard to identify, collecting all those beetles may give us an early heads-up on the next invasive--maybe early enough to eliminate or control it.  North America has already lost its chestnuts to chestnut blight, most of its large elms to Dutch elm disease, and it's rapidly losing ashes --some of the most majestic forest trees remaining.

I don't want to lose any more.

I hope to God not to find a half-inch long, narrowly oval, metallic emerald green beetle among the wasps' prey.  But if I don't find any this year, I'm sure I will next.

Saturday, July 4, 2015

Fourth of July on Nippenicket Pond

For years we followed a tradition of celebrating the Fourth and my youngest son's birthday at the same time with a cookout and family gathering.  But the family is changing, not everyone is as mobile as they were, and anyway we will be gathering tomorrow for our Sunday meal.  At loose ends, I decided to load the kayaks on the minivan and take the boys out on Nippenicket Pond* for the first time this season. 

The boys are old enough to paddle alone, so once we were all afloat, we went our separate ways: the boys to explore, I to be continually distracted by wildflowers and birds.

I'm calling this a bullrush (a broad, elastic term), but can't yet say exactly what it is.
You can see the white, curly stigmas projecting, ready to receive pollen.

Pickerelweed (Pontederia cordata) is a pretty plant common to ponds.

 Three-square (Scirpus americana) is fairly distinctive in having three-sided
stems with the flower cluster projecting from the side of the stem.

Yellow loosestrife or swamp candles
(Lysimachia terrestris) forms large colonies.

I drifted awhile in this tiny cove.

A colony of pickerelweed.

 This pretty little flower is unknown to me,
and I haven't succeeded in keying it out yet.


White waterlily (Nymphea oderata) is common in ponds,
but not the less pretty or sweet-smelling.

 This great blue heron may be the same one that approached a woman who was fishing.  
"I'd caught a sunfish," she told me, "so I tossed it in her direction, and she
took it and flew away."  When I came upon the woman, she stood on shore 
with a tablet in her hands; I thought she had found a nice place to read, 
but really she was uploading video of the heron.

The pond has a couple of islands big enough and high enough to walk around on.  I went ashore on the smaller of the two when I saw flowers I couldn't reach from the boat.  I walked around a bit.  Then I saw the boys, and we stayed close after that, as I delightedly chased a pair of kingfishers that were apparently nesting on the island.  These were my first kingfishers!  (I try to make up in enthusiasm for birds what I lack in experience.)

On the little island.

I had never seen the spore-bearing fronds of royal fern (Osmunda regalis).

Trevor, my 18-year-old, is paddling my blue skin-on-frame kayak, Musketequid.  Stephen, my 14-year-old, has my yellow plastic kayak, Toyboat.

 Yellow water lily (Nuphar advena) is less common than white water lily.
With such a different flower, it's hard to believe the two are in the same family.

The kingfisher pair were probably nesting on the island: they did NOT
want me hanging around, and one or the other circled and scolded almost constantly.

*I can't bring myself to use the official name "Lake Nippenicket" for a mile-long pond that never gets more than about six feet deep.  One sensible definition of "lake" is a body of water big enough that sunlight does not reach the deepest parts of the bottom.