St Croix River Road Ramblings

Welcome to River Road Ramblings.

Friday, December 7, 2012

Sex, Violence and Tragedy on the Blue Bird Trail

On my Facebook postings, got to talking about High School Spanish class--and Rodger Meyer, our teacher   This story comes from an invitation from Rodger to join him on a weekly Blue Bird trail excursion.   

Sex, Violence and Tragedy on the Blue Bird Trail written June 2011

Rodger Meyer invited me along to check some of the 80 bluebird houses he inspects weekly in the St. Croix Falls area.   We found conditions that matched those of “Desperate Housewives”— scandals, infidelity, violence and tragedy.  We also found bird families with the love and support of Pa and Ma Ingalls. 

Rodger monitors the birdhouses each week from spring through the summer, chronicling the return of the birds, their courtship, nest building, egg laying and incubation. Then he watches the hatchlings turn into fledglings recording each stage for The Bluebird Restoration Association of Wisconsin.. 

Cornell University says: “The male Eastern Bluebird displays at his nest cavity to attract a female. He brings nest material to the hole, goes in and out, and waves his wings while perched above it. That is pretty much his contribution to nest building; only the female Eastern Bluebird builds the nest and incubates the eggs.”

“Eastern Bluebirds typically have more than one successful brood per year. Young produced in early nests usually leave their parents in summer, but young from later nests frequently stay with their parents over the winter.”

“Eastern Bluebirds occur across eastern North America and south as far as Nicaragua. Birds that live farther north and in the west of the range tend to lay more eggs than eastern and southern birds.”

“Eastern Bluebirds eat mostly insects, wild fruit and berries. Occasionally, Eastern Bluebirds have also been observed capturing and eating larger prey items such as shrews, salamanders, snakes, lizards and tree frogs.”

“The oldest recorded Eastern Bluebird was 10 years 5 months old.”

“Eastern Bluebirds live in open country around trees, but with little understory and sparse ground cover. Original habitats probably included open, frequently burned pine savannas, beaver ponds, mature but open woods, and forest openings. Today, they’re most common along pastures, agricultural fields, suburban parks, backyards, and golf courses.”

“Insects caught on the ground are a bluebird’s main food for much of the year. Major prey include caterpillars, beetles crickets, grasshoppers, and spiders. In fall and winter, bluebirds eat large amounts of fruit including mistletoe, sumac, blueberries, black cherry, tupelo, currants, wild holly, dogwood berries, hackberries, honeysuckle, bay, pokeweed, and juniper berries. Rarely, Eastern Bluebirds have been recorded eating salamanders, shrews, snakes, lizards, and tree frogs.”
Rodger gave me a blue bird house to put up.  “Use a predator guard on your steel post so the nest will be safe.  I like a 1.5 inch plastic pipe over the post—harder to climb up the smooth plastic.  It still won’t stop wrens or house sparrows from taking over the nest.  Put bird house on the edge of a mowed grassy area so they can see the bugs. 
We left for the trail at 10:00 am.  “We’ll check some at the fair grounds first.  The boxes there have been put up by the Boy Scouts.”  We came to our first box.  It was one with a slanted front.  Rodger pulled a loose nail from the side of the box and gently tipped the door open.  “You have to be very slow opening the box.  If the young are almost ready to fledge (fly), they might get excited and leave the box too early, before they are really ready.”
We saw a clump of baby birds looking at us as we peered in the deep nest.  “Bluebirds mostly have a nest made of grass, sometimes with some pine needles.  With three or four babies, it is a snug fit; once in a while you get five or six—a real crowd.  I don’t try to count the hatchlings. I have counted the eggs before they hatched, and when the birds leave I look for any whole eggs left behind.  In a poorly constructed nest, eggs slip down too far to receive the heat from the female and don’t hatch.  So, if there were five eggs and one is left behind, I count four fledglings.” 

At each nest, Rodger fills in the box on his clipboard survey form.  The notes are “5 eggs” or “hatchlings” or “fledglings” etc.  One box on the east fence across from the grandstand, we found a nest being built.  “Looks like a bluebird nest—was empty last week.”  We watched a few minutes as a pair of bluebirds landed nearby on the fence, worried about what we were doing with their nest. 

A hundred yards further along the fence was the next house. “Russ, you try opening one box,” Rodger encouraged me.  He is looking for someone to help or maybe take over the monitoring—“You know, I’m over 80—can’t be sure I can continue in the future.” 

I tapped on the box lightly so any parent bird would fly out.  Then I removed the nail and very slowly tilted the front door towards me.  “Doesn’t look good,” I told Rodger, “looks like a dead baby bird.”   He joined me and we reconstructed the crime.

He pulled the nest out of the box.  It had only one baby.  “Looks like a little over a week old.  Look under where the nest was – see the blowfly larvae.”  He picked up a slowly wiggling grub from several that had been under the nest.  “They crawl up at night and suck blood from the babies—sets them back a little, but usually doesn’t kill them.”  
“Look—two more dead birds here on the ground,” I commented looking two feet in front of the nest.  They didn’t appear to have been eaten or chewed on.  We looked at the box closely—“see the scratches on it,” Rodger commented, “must be a predator climbed the box and pulled out some of the hatchlings.  This is a bad place for a house—it is on a steel post holding the woven wire fence for the grandstand—too easy to climb to the house and reach in.  You have to make it harder for the predators.   Last year at fair time, the grounds people put up a plastic snowfence and it covered the hole in this box.  I got here too late and there were four dead babies inside.  You know, I bet the new nest in the birdhouse we checked down the fence is where the bluebirds are starting over.”  We cleaned the nest out and moved on. 
We found a range of bluebird progress.  A few nests with 4-6 blue eggs, some hatchlings and some with feathers getting ready to fledge.  “If you clean out the house after they fledge, the bluebirds will build a new nest and do it all over again,” commented Rodger, “sometimes even three batches in a season.” 

We found a nest that had the top lined with feathers.  “Tree swallows like bluebird houses.  They are nice birds too, so we let them be. The only birds we don’t leave are English Sparrows and starlings.  Don’t get much sparrows unless you are on a farm or in town by a feed mill or on a horse lot—they eat the grain waste.  Don’t see much of them away from farms.  It is pretty much a waste of time putting a bluebird house next to an active barn.”
The swallow nest had six very light colored eggs—almost white.  As we looked at the nest, three tree swallows dive bombed us.  “Why are there three swallows?” I asked naively.  “Well, birds have some various family types.  Sometimes a male will have two females; sometimes young bluebirds will help their parents with the next batch; and sometimes you don’t really know what is going on.”  The tree swallows were iridescent blue/green with a very nice shine when the sun hit them right. 

At the third box in Interstate Park, Rodger checked his clipboard, “You get to see a Chickadee nest here.  Don’t see them very often.  They moved into this house that normally has bluebirds in it.”   We walked over and a bluebird flew out.  “Something going on here,” said Rodger, as he opened the box and we saw a double height nest—two distinct layers.  “Oh” said Rodger with a sigh, “the bluebirds put a nest right on top of the Chickadee eggs and nest.  That’s a shame. I like the little Chickadees; it’s fun to have a house of chickadees.  Usually something moves in on the bluebirds, but not this time.”
“Bluebirds have personalities that are different.  Some are aggressive towards other birds and put up a fuss when you come near their nest.  Others are quite the opposite.  One spring after the bluebirds returned and had nested, there was a long cold spell and I worried that they might starve.   I put a little tuna can on the top of the box and put in a few meal worms every day.  Some birds hovered around waiting for me to back off so they could eat and others never touched the worms at all.  I don’t know if it did the birds much good, but it made me feel better.  Once in a while you find dead hatchlings due to a cold spell. The parents can only find enough bugs to keep themselves alive. One cold spring I found 19 dead adult swallows among several boxes.”