Unnatural Selection: Cardinals, Cowbirds and the Mob

There seems to be something attractive about plant stands near our front and back doors.  So far, we have tried to assist in three attempts by Carolina Wrens to use them as nesting sites,

Carolina Wren nest in plant stand in our backyard.

Carolina Wren nest in plant stand in our backyard.

which makes getting in and out of our house a little trickier than normal.  But we did our best and managed to help one out of three nests actually succeed in fledging young wrens.  Between disturbance of the nest by us and interference by cowbirds, life was tough for young feathered parents in these parts. And now it was happening again, but not with wrens.

This time our backyard and garage had become our main way in and out of the house.  We were resigned to stop using our front door for a while.  After all. the garage and back door could get us in and out almost as fast, and using them wouldn’t disturb the nesting cardinals in the front.

The lovestruck pair had chosen a planter in our entryway for their domicile, a scant foot or two from the door, and in no time at all had populated it with an egg.  We watched, moving slowly past the window and trying not to frighten the mama bird off her egg.  When she left of her own accord, we would sneak out, peer into the nest and snap a photo or two and duck back inside before anybody got too upset.  Finally, we hung a sheet over the window to preserve the birds’ peace and harmony and just peeked carefully on occasion.

Soon, on one of our quick excursions to look into the nest, we found the other egg.  It had an amazing resemblance to the cardinals’ egg, but was smaller and had some subtle variations in color and pattern.

Cowbird.  Just like in the wrens’ nests.  Damn.

The cardinals were fighting back, though, and pretty soon a second large egg showed up.

Cardinalis cardinalis (Northern cardinal)  eggs with Molothrus ater(Brown-headed Cowbird) egg.

Cardinal eggs with smaller cowbird egg

A dilemma.  I posted the above photo on Facebook and queried friends about how we should handle this—let things work themselves out or remove the cowbird eggs and give the cardinals a fighting chance?  Most replies were pro-cardinal and anti-cowbird, but then one old friend from my college days posted, “I am curious, why mess with natural selection?  I am all for survival of the fittest. Otherwise, I wouldn’t be here, and neither would you.

So, there it was.  There would be no escaping this existential decision, this examination of values and subsequent action or inaction that would have consequences either way.

I think a little background is called for here.

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The egg of interest here was that of the Brown-headed Cowbird (Molothrus ater), which is a common bird around these parts and very pretty in its blackbirdy sort of way.  My favorite thing about the cowbird is its warbly, beautiful, difficult to describe call.  It sounds like, well….liquid.  A buddy stopped by one day and when a cowbird vocalized he turned to me and said, “Do you have water running somewhere?”  It’s kind of like brook water over clean stones.

Most people’s least-favorite thing about the cowbirds is that they are obligate “brood parasites” that do not build their own nests, but use other birds’ nests to lay their eggs in.  Here’s where the values come in, our natural human response to perceived unfairness.  “You mean, these nasty little birds let someone else do all the work, then swoop in, cut to the front of the line and take over?”  Well, yeah, kind of.

Not only that, but they often toss out the host family’s babies in the process.  “The cowbird’s egg usually hatches a day or two before the host’s eggs. Rapid growth allows the cowbird chick to out compete the host’s chicks for food and space in the nest. The result is that the host’s chicks usually perish.”

And it doesn’t stop there.  If the host birds try to protect their nests by removing the cowbird’s eggs, there is evidence that the cowbirds will retaliate by damaging the host nests and destroying host eggs or young, a process referred to as “mafia behavior”.  One study indicated that nests that ejected cowbird eggs actually produced fewer host offspring than nests that accepted the eggs!

I mean, really?  Is it so hard then to see why most people recommended getting rid of the cowbird’s eggs and saving the cardinal chicks?  I mean, these are unpleasant matters.  But, as my contrarian friend suggested, the cowbirds are just trying to get by doing what they were made to do, like all of us. They don’t hate the cardinals, and I doubt that the cardinals hate them.  It’s business, not personal.  So, why punish them, why interfere?  Should our human-centered values about fairness in human transactions really apply to the world of natural selection and instinctive survival?  Or are those two worlds really separate at all?

Do we have any responsibility here?  Maybe.  You see, cowbirds live life on the edge.  Not in the sense of adrenaline-pumping high adventure, but in the sense that they historically prefer the boundaries between forest and clearings, avoiding the forest interiors where nesting birds were pretty much safe from them.  They were also fond of the mid-American prairies and were thought to have followed the vast bison herds in their magnificent meanderings.

But then along came you-know-who, altering habitats, cutting down forests, plowing up the prairies, and generally doing a lot of cowbird-friendly things.  Suddenly there was a lot more “edge” than there used to be, a lot more short-grass and row-crop habitat that favored these opportunistic birds.  And they have thrived.  They have spread and increased and gone forth and multiplied.  Here in urban-world it’s basically all edge and cowbirds love it.  Who’s responsible for that?  Natural selection?

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So here it was, right outside our front door.  A battle between two species with different reproductive strategies, one of them aided by me and mine, historically speaking—the other just trying to carry on.  And now a second cowbird egg appeared making it two against two, but hardly even.

We made an executive decision, Nadia and I, maybe thinking of the beauty of cardinals on snow-covered boughs or maybe thinking that the builders deserved the rewards, instead of the usurpers.  At any rate, due to whatever combination of values driving us, we removed the cowbird eggs.

And soon:

Northern Cardinal Chicks

Northern Cardinal Chicks

---and hungry ones at that!

—and hungry ones at that!

We continued to monitor the nest several times a day, and I wish I could end this on a cheerful note, but life is seldom so simple, I suppose.

A few days later we checked when the mother was off the nest and found only one chick.  I went out and searched the immediate area, hoping that the nestling had simply fallen out, but there was nothing.  Later that day, the mother was back, caring for the second baby.  A day or two later, that chick also disappeared.  Again, I went out and searched the entryway and the surrounding yard.  The parents were agitated and moving around an adjacent sweet-gum tree, uttering little “pips” of alarm.  They actually got quite close to me as I searched.  Again, nothing.  The nest was then abandoned and still sits in the plant stand outside our window.

What happened?  Squirrels will take nestlings for food, but we had never seen one near our front door.  Crows will take baby birds, too, but we have never seen them in our yard at all.  Cats?  Maybe.  I have even witnessed a bluejay chasing down a young bird, killing it and eating part of it.

Or could it have been the Cowbird Mafia?  We will never know.  Nobody’s talking….

Postscript:  The day after the second chick disappeared, I was sitting and reading in our living room, which is slightly below ground level.  I heard a scrabbling sound and then a tapping against the glass of one of our windows and I looked up to see the head of a female cardinal peering in and seeming to look straight at me.  She disappeared and I went back to my book.  Minutes later, there was another tapping on the glass and the cardinal appeared at a different window, again seeming to stare directly at me.  She tapped her beak against the glass, stared, tapped and stared again.

She watched for a moment, then vanished.

I didn’t see her again.

 

 

 

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Pests and Parasites

A very effective agent of biological pest control, this tiny wasp in our backyard is preparing to lay an egg on (or in) the little green aphid.. When the egg hatches, it will live inside the aphid, munching happily away, until it emerges from the hollowed-out host as an adult wasp. The wasp is about the size of a fruit fly or smaller. The light colored husk next to the green aphid is another aphid that has already been parasitized.  Like the movie “Alien”.  But real!

There are many species of wasp that keep insect “pests” (meaning those that people don’t like) under control.  A very good reason not to bomb yards with insecticides.  You might get a mosquito-free evening, but it kills everything—including the good stuff.

Parasitic wasp aphid

Parasitic wasp prepares to lay egg on aphid

Below is another wasp trying to pass on the family genes, surrounded by parasitized aphids that are feeding the next generation of parasites.

Wasp apid parasitism

Wasp surrounded by parasitized aphids

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The Return of the Stinker

Hard to believe but stuff’s coming up!  Not just the ubiquitous daffodils that pop up just in time to tease us about a yet-distant spring, but other stuff.  Like Wild Leeks.  Yeah, smelly old Allium tricoccum.

What is this plant and why should you care?  Inquiring minds will check it out in our native plants section here for the low-down, a recipe from Nadia, and links to other recipes and fun stuff.

Smelly.  But delicious.

Wild Leeks (Allium tricoccum)

Wild Leeks Coming Up in Late Winter
(Allium tricoccum)

Wild Leeks (Allium tricoccum)

Baby Wild Leek
(Allium tricoccum)

 

 

 

 

 

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Winter Rations

Liquidambar styraciflua

Goldfinch Eating Sweet Gum Seeds (Liquidambar styraciflua)

I’ve often thought of our Sweet Gum tree as more of a Bitter-Sweet Gum tree, mainly when I rake up piles of the spiky little balls it sheds with great joy and abandon.  I think I am not alone in this.  But then I reflect on the fact that the universe really doesn’t revolve around me and my kind, despite our illusions to the contrary sometimes, and that this wonderful tree has lots of benefits.

Just ask the goldfinches when they flock into its branches and spend hours snacking on its seeds outside our window.  Even with feeders available nearby, our sweet gum is a popular stop for these birds, plus many others who like to nest in it.  It’s also a great shade tree, so I’m grateful for it in the end.

I’m also grateful that nobody reported someone suspiciously hanging out of our upstairs window with a camera pointed in the direction of the busy street, passersby, and our neighbors houses…..  I guess they’re just used to us by now.

I will try to add a page on the Sweet Gum to our native plants section in the near future, so stay tuned.

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To All Things a Season

Walter Tindall on one of his tractors

Walter H. Tindall, 1934-2012.

He was a husband, father, grandfather, friend to many, veteran and farmer, like his father before him.  He loved the land and the work and the trappings of farming, and he loved his family.

Dad liked his nature tidy and kept his farm and fields manicured.  Ask anyone around town—they’ll tell you.  To this day, he is the only farmer I ever knew who would wash and wax his equipment, up to and including combines.  He had little time for things like milkweeds and other “weeds”, but he planted and nurtured hundreds of trees on the little acreage where we lived and loved watching the birds that thrived in them.  He watered those trees for uncounted hours with a tank pulled by one of his shiny tractors, and when he mowed, as he often did, he was known to get down and trim neatly around the trees with a pair of scissors.  Hundreds….of…..them.  Like I said, he liked things tidy.

And you know what?  Because of that and many other things he did, I’ll cut him all the slack he wants on the milkweeds.

We’ll miss you, Dad.

 

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Galls Galore

Besides having some spectacular fall colors this year, another thing our drought didn’t seem to hurt was the prevalence of oak leaf galls.  I’m not sure why, but we seemed to have a bumper crop of them this year.

Oak Leaf Galls

Pin Oak Leaf Galls seemed to like the drought.  At least somebody did.

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Fall Medley #1

Fall Leaves Medley

The severe drought hasn’t dimmed the autumn colors! All from our backyard!

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Hitting the Trifecta

It’s not often—or ever before, to be honest—that I’ve had the chance to photograph several stages in an insect’s life journey in just a week or so, but I think I nailed it recently.

We’ve got some wild senna growing happily in our yard and one day Nadia and I noticed some caterpillars feeding on the flowers.  I took some pics and wandered over to my favorite caterpillar identification site and tentatively identified it as a Cloudless Sulfur caterpillar (in a somewhat roundabout way).

Cloudless Sulfur larvae

Caterpillar of the Cloudless Sulfur (Phoebis sennae)

Not many days later, we noticed a very busy yellowish butterfly flitting around the plants, pausing very briefly, then moving on, over and over.  I manage to get a quick snapshot. Having watched this sort of behavior before, I thought “I bet she’s laying eggs.”

Adult Cloudless Sulfur

Adult Cloudless Sulfur Butterfly Laying Eggs

Sure enough, I marked a spot where the little lady had just paused and went over for a closer look.  Guess what?

Cloudless Sulfur egg

Freshly deposited egg of a Cloudless Sulfur butterfly

I later moused over to Bug Guide and checked to see if the butterfly just might match the caterpillars.  It did!   When I realized that we had just seen one of our yard citizens go from egg to adult almost in front of our eyes, it almost brought a little tear to mine.  They just grow up so fast….sniff.

Nadia?  She just thought it was way cool.

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Note:  If anyone ever notices an incorrect identification in any of these posts, PLEASE let me know!  I would really appreciate it!

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Where have all the berries gone?

This is what the fruiting head of Pokeweed (Phytolacca americana) often looks like after the berries have matured.  What berries, you say?  Ask the birds that ate them all, especially the robins that love to gorge on them and leave colorful little patches of seed-containing excrement around the neighborhood.  The pokeweed and robins team up to make sure that the plant reproduces and the birds have a future supply of more berries.

Everybody’s happy (except maybe people who get annoyed at purple patches on their cars parked in unfortunate places and on their sidewalks and patios).

Hey, you can’t make everybody happy all the time….

Note:  The title should be sung to the tune of “Where have all the flowers gone?” by Peter, Paul and Mary.  But you knew that.

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There Be Giants Here!

Giant Swallowtail (Papilio cresphontes)

Newly hatched Giant Swallowtail (Papilio cresphontes)

Found this in our backyard today, so new that it’s wings weren’t even fully expanded.  A big surprise, considering the dearth of butterflies this season, at least here.  We’ve never seen this one before, but I think we’ve seen its caterpillars.  They look like, well, bird poop.  I have some photos of the larvae somewhere, and when I find them I’ll post them.  I suspect that this magnificent butterfly was nurtured on our Wafer Ash, since they like citrus and this tree has some citrusy connections, Nadia tells me (plus I seem to remember finding those poopy caterpillars there).  I have read that this is the largest North American butterfly.  I can attest that it is certainly big, with a 4-5 inch wingspan.

It was a refreshing discovery in the middle of our severe drought and heat.  I wish it well.

Giant Swallowtail (Papilio cresphontes)

Giant Swallowtail (Papilio cresphontes). Front view.

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