Outside My Window

At rush hour last night, a river of crows flew over Fifth Avenue and perched in the trees on Wilkins.  That event and last week’s robin roost prompted me to think about flocking behavior. 

We’ve all noticed that birds flock in winter.  It turns out that flocking is usually a trait of social species, such as crows and parrots, and species whose food sources are abundant: omnivores like gulls and starlings, seed-eaters like blackbirds and finches.  But why to they do it?

The first reason is defense.  It’s harder to be caught unawares if you’re in a flock with many watchers and it’s statistically quite safe.  At the robin roost we heard a pair of great-horned owls but each owl will catch only one bird per night, leaving an individual robin with a 0.002% chance of becoming an owl meal.

Another flock advantage are the many eyes searching for food.  If the food source is abundant - a seed field or a landfill - everyone gets a meal.  Obviously, flocking doesn’t work for birds like red-tailed hawks who catch their prey by stealth. 

Social species enjoy flocks.  Crows get smarter by being with each other.  As Candace Savage said in Crows: Encounters with the Wise Guys:  “Nothing is more intellectually challenging than living in a social group, surrounded by a bunch of other animals that are sharpening their wits on you.” 

The most spectacular flocks are made up of starlings who wheel in unison without an apparent leader.  Tom Pawlesh took this photo of a spectacular “cloud” of starlings.  Not all birds fly in a tight formation like this.  When it comes to flocking, starlings are the champs.

News of the huge robin roost first came from Scott Kinsey when he asked for help counting them.  ”To anyone who thinks robins flew south for the winter, take a look at this.  I hope to figure out how many thousands are at this roost.” 

Dave Wilton helped him count 25,000 but they didn’t have a good vantage point.

At dawn a few days later in a wooded valley, Dave Wilton witnessed a “100,000 bird explosion… in what can only be described as a nuclear detonation of birds roaring into the sky.”  He had found the roost.

That evening Geoff Malosh watched “how utterly spectacular this robin roost in Allegheny County really is.  …I am not at all uncomfortable in guessing that there are actually six digits worth of robins. …It really is an incredible sight.”

Birders flocked.  I was there for both sunrise and sunset today.

In the dark before dawn, the robins called softly to each other but there was no activity… yet.  About 1/2 hour before dawn they began to fly up, not by skimming the treetops but by shooting straight into the sky.  They were not in tight flocks.  They were everywhere.  By dawn the whole sky was thickly peppered with robins flying in every direction.  Thousands and thousands and thousands of birds. 

It was over as fast as it began.  By 1/2 hour after dawn, they were gone.

Dusk was different.  Half an hour before sunset the flocks approached the site but did not roost.  Instead some flew around it, some perched.  By sunset all the birds were flying and again the sky was thickly peppered with an incredible number of birds.  As I watched through binoculars I noticed the furthest birds were flying right to left, the nearest left to right.  They were circling the roost counter clockwise!

As the sky darkened small flocks broke off and disappeared to roost in evergreens.  By 1/2 hour after sunset, they were done.

This phenomenon leaves more questions than answers.  Why did they choose this place?  How did they find it?  Do they come here every year?  When did they begin roosting here this fall?  How much longer will they stay? 

And just how many robins are there?   No one can say.

I am not a morning person, but I want to be, so I get up an hour before I need to, drink a mug of coffee, and I wait to wake up. 

Sometimes - even in cold weather - I sit on the front porch and watch the birds go by.  Their rush hour happens overhead.

In winter the first to fly over are the crows, northeast to southwest.  This morning the first flock numbered more than 300 and passed by before dawn.  Crow flocks continue at mid-altitude throughout bird rush hour.

The cardinals and song sparrows wake up next and exchange a few contact calls.  No flocking for them.  They just want to make sure their friends made it through the night.

Then mourning doves wake up and zoom by in small, fast groups. 

Next come the starlings and robins.  The starlings roost at the Birmingham Bridge and fan out in all directions at dawn, moving fast just above the rooftops.   The robins roost near the Bloomfield Bridge and fly in loose flocks at high altitude. 

Normally the birds manage to avoid congestion by picking different altitudes but this morning it was foggy.  A couple of starling flocks and robins had to divert to avoid the crows.  I could hear the robins commenting about it.  “Watch out there,” they seemed to be saying. 

And by then I was awake.  Time to join the human rush hour.  (That’s the Parkway East pictured above via my cell phone.)

Last night I went to Three Rivers Birding Club to hear Dr. Todd Katzner of the National Aviary give an excellent presentation on “Migrating Eagles and Wind Turbines: Resolving Conflict in an Information Void.”   The project is a multi-year study of the migratory paths of eastern golden eagles.  Its goal is to provide information so that wind turbines can be sited properly and not cause bird mortality.

Wind energy is being heavily promoted and developed in Pennsylvania.  I’m sure you’ve seen windmills if you’ve driven east on the Turnpike.  Many more wind farms are planned.

Some wind turbines are highly lethal to birds.  Some don’t kill any.  It turns out that turbine placement is the key.  If we find out where the birds usually fly, the turbines can be placed outside that path.  Sometimes only a few hundred feet makes all the difference.

The coolest part of the project is the telemetry data and maps.  It’s impressive how far golden eagles travel in a day (more than 200 miles) and how fast they go when the wind is good (60 miles per hour!).  On the Aviary website you can see where all seven eagles have been and you can watch the day-by-day movements of each eagle. 

The project needs to tag more eagles with telemetry units but the units are expensive.   The Aviary and their partners are working at raising funds to buy telemetry units.  Contact Dr. Todd Katzner at the National Aviary if you wish to help.

At lunch time my friend Karen and I walk Pitt’s campus near the Cathedral of Learning to see if we can find the peregrines.  Today we found a bird we hadn’t seen since last spring - a northern mockingbird. 

All last winter and into early spring we usually saw a mockingbird perched high on the hedge in front of Heinz Chapel.  He (or perhaps she) became more active and territorial as spring approached.  I hoped he would nest on campus, but he disappeared before nesting time.  Now he’s back.  

The photo above, by Marcy Cunkelman, is not our Pitt mockingbird but he is in a typical pose.  Marcy’s mockingbird looks puffed out because he is trying to stay warm but his ’stare you down’ look and his cocked tail are just like the bird Karen and I see near Heinz Chapel.

Our mockingbird is probably a winter visitor.  Northern mockingbirds, despite their name, used to be a southern species and did not nest in western Pennsylvania.  For the past century they have been expanding their range northward.  Our winter mockingbird’s habits suggest he breeds so far north that a Pittsburgh winter feels mild.

How do I know he wasn’t here all year?  Mockingbirds are hard to miss at any season.  Not only do they sing nearly all year - and will sing all night in the spring - but they love to perch in plain view.  They are very territorial and noisy in nesting season.  Last spring I participated in the 2nd Pennsylvania Breeding Bird Atlas project so I looked for this bird, hoping to confirm that mockingbirds were nesting near Heinz Chapel.  No.  Oh well. 

How do I know it’s the same bird every year?  Well, I don’t.  But he follows the same routine and has the same favorite perches.  For his part, he is probably thinking that he cannot be sure I am the same human who looks at him every winter but I seem to follow the same routine and walk past him at the same spot at the same time of day.

Funny how that works both ways.

Fog:   Today I took a vacation day to go to the Allegheny Front Hawk Watch on Allegheny Mountain just inside Bedford County.  The weather was supposed to be great for watching hawks - an east wind and sun - but there was no sun.  Instead thick freezing fog which deposited icy feathers on the trees as you can see from the picture I took with my cellphone.  Notice that the sky is white.  That’s the fog.

Bummer.  I drove two hours only to find out it was fogged in.  In fact, the edge of that mountain was the only place totally fogged in.  Knowing the weather for the nearest town, Central City, is no help.  The only way to know what the weather is like on the mountain, is to be there.

Coal:  Don’t let anyone tell you coal is ‘clean’ energy.  There’s a huge active strip mine south of Central City.  Loaded coal trucks leave the site every few seconds and drive on Routes 160 and 30.  The coal dust from these trucks lines the road, coats the roadside vegetation and splashes up on the cars.  When they say coal towns are gritty it is literally true.

Ducks:  Rather than go home I went down to Shawnee State Park in the valley near Schellsburg.   It was overcast and chilly but nicer than the mountain.  There were four common loons on the lake, a flock of ring-necked ducks, hooded mergansers, a few black ducks, mallards and the best bird - three long-tailed ducks. I have not seen long-tailed ducks since 1997 so these were a special treat. 

I know the ducks will leave tonight.  Two duck hunters with a black Labrador retriever arrived at 3:30pm and set out decoys.  I hope the ducks are not fooled and that they all escape - especially the long-tailed ducks.

Yesterday was a gray, drizzly day and a great birding day at Moraine State Park in Butler County.  I went there to see ducks, hoping to find Tundra Swans. 

Moraine State Park was built in 1970 from strip-mined land assembled by the Western Pennsylvania Conservancy.  Its centerpiece is a 3,225-acre lake formed by the damming of Muddy Creek.  Lake Arthur is one of the few large lakes in western Pennsylvania and a major stopover for migrating waterfowl.

When I got to the Pleasant Valley beach area there were many ruddy ducks and coots, but the big surprise was around the corner at the south shore overlook.  In the middle of the lake were hundreds of common loons.  Birding friends of mine counted over 300.  This is truly amazing because loons migrate alone or in small groups and are rarely seen in large numbers.  In one glance I saw more loons than I’ve seen in my entire life.  A loon fallout!

The word fallout usually means something bad - radioactive fallout from a nuclear explosion or political fallout from a bad decision - but in birding it’s exciting.  When migrating birds hit bad weather, the flocks have to land.  This results in so many birds in one place that they seem to have fallen out of the sky.

So why loons?  I can only imagine it happened like this:  On Saturday evening fifty or more small flocks of loons each made the individual decision that it was time to leave the Great Lakes for the coast.  They all headed southeast for Chesapeake Bay but when they reached western Pennsylvania they found the leading edge of bad weather, fog and rain.  They realized it was only going to get worse so they had better land at Lake Arthur.

Loons have few choices on where to land.  Because they eat fish for a living, they are excellent divers but their bodies are heavy and hinged incorrectly for walking.  If they land on anything except a large area of open water, they cannot take off again and will die, stranded.  Lake Arthur was their best - perhaps their only - choice.

Chuck Tague once found a common loon on a beach in Florida, pictured here.  It may not have been stranded because the tide was going to come in, but it was definitely out of place.  As you can see, the loon’s legs are far back on its body, making them good for swimming, but not good for walking.  This loon is in winter plumage, mostly a uniform gray instead of the striking black and white pattern of breeding season.  The loon’s belly is white but you can’t see the belly when they are riding the water. 

After watching the loons for a while, I parked and hiked.  It was cold so I walked fast and finished early.  Again I drove the south shore loop to see if anything changed.  This pass was even better.  The loons were still there but this time I saw three bald eagles.  An adult pair (the male is noticably smaller than the female) circled up around an immature eagle.  Immature bald eagles are brown with blotchy white on their bodies.  Their heads and tails are not white.  The adult eagles seemed to be showing the young eagle that they claimed the lake as their territory.  They didn’t chase him, just gave him a show of strength. 

And my Best Bird of the day was there too.  Perched on a bush at the water’s edge was a Northern Shrike, a rare northern visitor.  What a cap to my day!  The only way to improve it would have been if I’d seen Tundra Swans.

This morning outside my window I watched a flock of thousands of common grackles streaming toward Schenley Park.  The flock moved in a long thin line so it took several minutes for it to pass.  Just as I assumed they were done, even more appeared.

You can get an idea of it how they looked from Chuck Tague’s picture of a brown-headed cowbird flock.

Any day now tundra swans will move through western Pennsylvania on their way south to the Chesapeake.  A flock usually flies over my house at night in early November.  I know they’re overhead when I hear them calling as they fly, a “woo-ing” sound that, to me, resembles the voices of children playing in the distance.  If I’m lucky, I’m already outdoors and can see them illuminated from below by the city lights.  Otherwise I race for the door, burst outside in the dark – and usually miss them.

Tundra swans hold a particular fascination for me, partly because they rarely spend any time near Pittsburgh.  Those seen here in the fall generally spend the summer breeding in Canada’s Northwest Territory and Alaska’s North Slope.  In autumn they fly south and east across Canada, the Great Lakes and Pennsylvania, destined for Chesapeake Bay and North Carolina – a journey that covers 3,600 miles and takes about 12 weeks. 

I will never forget the time I watched a flock of tundra swans land at dusk on Yellow Creek Lake in Indiana County.  I was sitting in the Waterfowl Observatory blind, unable to see the sky.  Snow had started falling when I heard the voices of swans overhead.  As they came into view they circled once, then one after the other they cupped their wings and landed in a gliding V on the lake.  What a beautiful thing.

Come, swans!