Autumn’s Flying Ants

Citronella ant, Lasius interjectus, with wings (photo by Alex Wild via SmugMug)
Citronella ant, Lasius interjectus (photo by Alex Wild via SmugMug)

On warm fall days look up and you might see swarms of flying ants.  Flying high, they're annoying at hawk watches.  What are these ants and what are they doing?  The answer is more interesting than you might think.

Flying ant swarms are the mating dance, the nuptial flight, of winged male ants and virgin queens.  Each species has its own time of year for mating.

If you've never seen a swarm here's what it looks like, filmed at a tall grass prairie in Nebraska (20 seconds).

 

The ants are so preoccupied with mating that they don't pay attention to what's nearby and are easy prey for migrating dragonflies, cedar waxwings, and even ring-billed gulls.

 

Don't worry. The swarms are not termites. Termites make their nuptial flights in the spring and, if you look closely, they're different from ants.  Ants have pinched waists and "nodes" at their waistlines. Termites do not.  Here's a visual comparison -- not to scale -- of fire ants on the left and eastern subterranean termites on the right.

Compare body shape of two wingless insects: fireants and eastern subterranean termites (photos from Wikimedia Commons)
Compare body shape of two wingless insects: fire ants and eastern subterranean termites (photos from Wikimedia Commons)

 

In autumn in Pennsylvania the swarms are sometimes citronella ants, Lasius interjectus (shown at top) or Lasius claviger, described here by Penn State Cooperative Extension.  The name comes from their lemon smell when threatened or crushed.

Citronella ants spend their whole lives underground except when they emerge to mate.  They're actually "farmers" who tend their livestock -- aphids -- and harvest the aphids' honeydew.  This video describes a citronella ant colony.

 

After the nuptial flight the male ants die and the fertilized queens shed their wings.  They don't just shed them, they yank them off!  Watch this citronella ant use two of her six legs to pull off each wing (7 seconds).

And then the queen walks off to find an underground place to nest.

There are so many ant species that it takes an expert to identify them.  If you know which ones fly at the Allegheny Front Hawk Watch in September, please let me know.

 

(photo credits: citronella ant photo Lasius interjectus by Alex Wild via SmugMug, composite photo of fire ants and eastern subterranean termites from Wikimedia Commons.  video credits: Ant swarm in Nebraska by Evan Barrientos on YouTube. Citronella ants by Chris Egnoto - The Naturalist's Path on YouTube.  Ant yanking off its wings by David Shane on YouTube)

When Will The First Junco Arrive?

Dark-eyed Junco (photo by Bobby Greene)
Dark-eyed Junco (photo by Bobby Greene)

Since mid-September summer has lingered in Pittsburgh with temperatures spiking 15-20 degrees above normal.  Does this mean fall arrivals will be delayed?

Here's what normally happens outdoors in late October and early November.  Let's watch to see if it's on schedule.

  • Fall colors peak in mid-October, especially red and sugar maples.  The oaks turn red at the end of the month.
  • First frost in Pittsburgh around October 20.  First hard frost around Halloween. (Really?!?  Keep your eye on this one.)
  • Most trees will lose their leaves by November 8.
  • Most flowers have gone to seed though witch hazel, bottle gentian, hardy goldenrods and asters are blooming.
  • The warblers are gone but white-throated sparrows, dark-eyed juncos and American tree sparrows will arrive to stay through winter.
  • Broad-winged hawks are gone but red-tailed hawks, kestrels and sharp-shins are now on the move. Don't miss seeing golden eagles at the Allegheny Front Hawk Watch from late October through November.
  • Fill your hummingbird feeder in October in case a rufous hummingbird shows up.
  • Big flocks of robins, grackles and starlings form at dusk and dawn. The Pittsburgh crow flock becomes noticeable in early November.
  • The first wave of migrant ducks and geese arrive with October cold fronts.
  • Chipmunks, squirrels, and groundhogs are storing food and putting on weight.
  • It's hunting season. Wear blaze orange and be aware of Pennsylvania’s hunting seasons.  Remember: Though Sunday is generally safer, some game can be hunted on Sundays.
  • Be prepared to "fall back" on the first Sunday in November when we set our clocks to Standard Time.  After that, evening rush hour will be in the dark.

When will the first frost come? When will the first junco arrive?

Stay tuned.

For more information, see Chuck Tague's Western Pennsylvania Phenological Perspective for October, first published in 2010.

 

(photo by Bobby Greene)

Warming Up to the Next Ice Age

screenshot from This Is Not Cool with Peter Sinclair, Yale Climate Connections
screenshot from This Is Not Cool with Peter Sinclair, Yale Climate Connections

The ocean is warming, the ice sheets are melting, and the sea is rising. Does global warming mean we'll be warmer here in the northern hemisphere?  Maybe not.

In this video by Yale Climate Connections, Jørgen Peder Steffensen, an expert in ice core analysis from the Niels Bohr Institute, explains how the Earth can become hotter yet simultaneously plunge Europe into an ice age and North America into ice or drought.  It's a matter of distribution.

Here are some points that stunned me in the video:

  • In the last 1 million years there have been 10 ice ages.  Each ice age lasted about 90,000 years.
  • Ice ages aren't uniformly cold. Far from it!  Steffensen says, "Inside an ice age the climate is extremely unstable, and you have this sequence of abrupt climate changes [semi-cold to very cold] that happen basically from one year to the next."
  • In-between ice ages are interglacial periods of milder, more stable climate that last about 10,000 years. We're in an interglacial period right now.  It's already 11,000 years old.
  • Earth can have an ice age in one place and be hot elsewhere.  Ice cores indicate that when Greenland has an ice age, Antarctica is warm -- and vice versa.
  • Earth's current mild climate is due to a global distribution pattern of ocean currents and pressure systems that keep temperatures mild and rainfall moderate.
  • The global distribution pattern can change abruptly.  We don't know where the trigger is, though we do know our emissions add fuel to the fire.

As Steffensen says, "The climate does not play nice all the time,"

Learn more at Yale Climate Connections:  Humans experimenting with climate's 'playing nice'

 

(screenshot and video from This Is Not Cool with Peter Sinclair, Yale Climate Connections)

 

How Old Is That Peregrine?

Adult peregrine falcon in flight, Univ.of Pittsburgh, 2016 (photo by Peter Bell)
Adult peregrine falcon in flight, Univ.of Pittsburgh, 2016 (photo by Peter Bell)

Now's a good time to brush up on identifying peregrine falcons since they pass by hawk watches in October, especially on the coast.  When you identify a peregrine you can also tell how old it is because the plumage is different in each age group:  adult, juvenile, and sub-adult.

Plumage provides an exact age for two groups in October:  Juveniles are first year birds, 6 months old, that hatched last spring. Sub-adults are second year birds, 18 months old, with nearly complete adult plumage.

Adults -- two or more years old -- all have the same plumage.  Unfortunately you can't know an adult's exact age unless the bird is banded and you find out its provenance.

Here's what they look like:

Adult peregrines (2+ years old in October) have fresh plumage in charcoal gray and white.  The photo at top shows an adult male in flight.  The photo below is an adult female.  Adults have:

  • Solid dark charcoal helmet (head)
  • Dark charcoal malar stripes (on face)
  • Clean white or slightly rosy chest and throat
  • Horizontal charcoal+white stripes on belly and flanks
  • Gray back: Male's is pale blue-gray.  Female's is "muddy" gray.

Adult peregrine, Univ of Pittsburgh, 2017 (photo by Peter Bell)
Adult peregrine, Univ of Pittsburgh, 2017 (photo by Peter Bell)

 

Juvenile peregrines (6 months old in October) are the same size as adults but their colors are brown+cream.  Juveniles have:

  • Variable brown helmet with some cream-colored traces (head)
  • Brown malar stripes (on face)
  • Cream colored chest that's striped all the way up to the throat
  • Vertical brown+cream stripes on belly and flanks
  • Brown back.
  • (Bonus!) Juveniles have cream-colored tips on their tails, visible as the sun shines through them in flight.

Juvenile peregrine in flight, Univ of Pittsburgh, 2012 (photo by Peter Bell)
Juvenile peregrine in flight, Univ of Pittsburgh, 2012 (photo by Peter Bell)

Above, a juvenile in flight.  Below a juvenile shows off the vertical stripes on his chest and belly.  His variable brown helmet with "eyes on the back of his head" and horizontal cream-colored line at his crown.

Juvenile peregrine falcon, Univ. of Pittsburgh, 2016 (photo by Peter Bell)
Juvenile peregrine falcon, Univ. of Pittsburgh, 2016 (photo by Peter Bell)

 

Sub-adults are 18 months old with nearly complete adult plumage except for a few juvenile feathers.  They began to molt into adult plumage last spring at 10-12 months old.  By October their few juvenile feathers are hard to see without a photograph.  They are ready to breed next spring.

Below, an 18-month-old peregrine named Spirit is in rehab at Medina Raptor Center in the autumn of 2014.  You can see her back is mostly gray with just a few brown feathers.  Her head shows faint traces of the juvenile cream colors.

18-month-old peregrine falcon, Spirit, in rehab at Medina Raptor Center, Nov. 2015 (photo by Kate St.John)
18-month-old peregrine falcon, Spirit, in rehab at Medina Raptor Center, Nov. 2015 (photo by Kate St.John)

For a view of sub-adult plumage in the spring, see these photos taken in March 2016 of a 10-month-old Juvenile Peregrine Falcon Transitioning Into Adult Plumage.

For additional tips, see Ageing Peregrine Falcons in the Field by Alex Lamoreaux at Nemesis Bird.

 

(all photos taken at University of Pittsburgh by Peter Bell ... except for the peregrine on the glove, "Spirit" at Medina Raptor Center, photo by Kate St. John)

Cranberry Harvest Time

My sister-in-law describes how the floating cranberries are gathered (photo by Kate St. John)
My sister-in-law describes how the floating cranberries are gathered (photo by Kate St. John)

October is cranberry harvest time in Massachusetts.  Last week at Cape Cod my sister-in-law took us to see a flooded cranberry bog, red with floating cranberries.

Cranberries are native perennial vines that grow in sandy soil.  Before mechanization people used to pick them by hand, crawling around on their hands and knees as shown in this painting of Nantucket in 1880.

Jonathan Eastman Johnson: The Cranberry Harvest on the Island of Nantucket, 1880
Jonathan Eastman Johnson: The Cranberry Harvest on the Island of Nantucket, 1880

Nowadays the harvest uses machines and this unique quality of the cranberry -- it floats.

In the photo at top, my sister-in-law describes how the bog is dry during the growing season.  In the spring, honeybees are brought in to pollinate the cranberry flowers.  Then in October when the berries are ripe, workers flood the bog and use a thresher machine to knock the berries off the underwater vines.  The berries float, the workers corral the berries, and machines lift the cranberries out of the bog.

My husband went back a few days later to see the rest of the process.  Here the cranberries are corralled and shuttled up out of the bog into the large black truck.

Cranberry harvest at Cape Cod: the berries are lifted into the truck on the left (photo by Rick St. John)
Cranberry harvest at Cape Cod: the berries are lifted into the truck on the left (photo by Rick St. John)

A man monitors the machinery as cranberries tumble into the truck (photo by Rick St. John)
A man monitors the machinery as cranberries tumble into the truck (photo by Rick St. John)

 

This 5 minute video shows the entire process.

 

The cranberry harvest is underway this month in these northern states and provinces: New Jersey, Massachusetts, Wisconsin, Oregon, Washington, British Columbia and Quebec.

 

(photos of a Cape Cod cranberry bog by Kate and Rick St. John. Painting of The Cranberry Harvest on the Island of Nantucket, 1880 by Jonathan Eastman Johnson via Wikimedia Commons; click on the image to see the original.  Video from True Food TV via YouTube)

Where to Find Crossbills and Siskins This Winter

White-winged crossbill, 2012 (photo by Shawn Collins)
White-winged crossbill, 2012 (photo by Shawn Collins)

Will we see northern finches in the eastern United States this winter?  It depends on where you are.

Last month Ron Pittaway published his Winter Finch Forecast for 2017.  The good news is that northern finches are on the move.  The bad news for Pittsburgh birders is that they won't come this far south.

Northern finches such as evening grosbeaks, crossbills, redpolls and purple finches don't care about cold weather but they do care about food and that means seed cones on spruce, fir, pine and birch trees.

Pittaway says that seed crops in northeastern North America are excellent this year -- the best they've been in ten+ years -- so finches have already moved to those areas in good numbers.  In fact the seed crop is so good up north that purple finches and evening grosbeaks probably won't leave home this winter.

The Winter Finch Forecast predicts that if you're in central or northeastern Ontario, Quebec, Canada's Atlantic provinces, northern New York state, or northern New England, you'll see red crossbills (Loxia curvirostra), white-winged crossbills (Loxia leucoptera) and pine siskins (Spinus pinus) this winter.

But not here.  As he says, "This is not an irruption year south of traditional wintering areas in the Northeast."

Read the entire forecast here including predictions for three indicator species: blue jays, red-breasted nuthatches, and Bohemian waxwings.

The blue jay prediction surprised me.  We have a big influx of blue jays in Schenley Park right now. I wonder where they came from.

 

p.s. I saw red-breasted nuthatches at Cape Cod last week.

(photo of a white-winged crossbill by Shawn Collins, 2012)

High Tide Is Coming

Only eight years from now, high tide will be this much higher at Wellfleet Bay (photo by Kate St.John)
Only eight years from now, high tide will be this much higher at Wellfleet Bay (photo by Kate St.John)

Last weekend at Cape Cod I went on two outings at Massachusetts Audubon's Wellfleet Bay Wildlife Sanctuary led by Joel Wagner, a birder from Gettysburg, PA who now works at Wellfleet and Saco, Maine.

At low tide we visited the salt marsh and bay shore to look for shorebirds.  On our way there, Joel pointed out the Average High Tide markers with dates of future tides.  I was astonished to see that in only eight years the average high tide will move up from that distant 2017 marker to this one.

It's even worse in the decades ahead.  This photo shows the 2075 marker with the earlier years in the distance.  The 2025 marker is so far away that it's out of sight.  The trees in this photo will die when salt water reaches them.

Average high tide in 2075 will be here at Wellleet Bay (photo by Kate St. John)
Average high tide in 2075 will be here at Wellleet Bay (photo by Kate St. John)

The highest tides today, the spring tides, already swamp the 2017 marker.

Sea level is rising.  High tide is coming. Watch out if you live by the sea.

 

Unfamiliar with sea level rise?  Read more here at Yes, The Sea is Rising.

(photos by Kate St.John)

Staging At The Cape


Flock of Tree Swallows by Cindy Bryant on Vimeo, 12 Jan 2015, Central Florida.

Last weekend at Cape Cod I saw a swirling flock of tree swallows at their staging area.

Staging: Designating a stopping-place or assembly-point en route to a destination -- from The New Shorter Oxford English Dictionary.

Tree swallows (Tachycineta bicolor) breed as far north as the tundra/tree line in Canada and Alaska and spend the winter from Florida to Central America.  Their departure from western Pennsylvania is barely noticeable but on the East Coast they gather in salt marshes in huge flocks of a hundred thousand birds.  Their interim stops on migration are called staging areas.

In the evening tree swallows funnel down to the marsh in a tornado of birds.  At dawn they burst up from the roost, as shown in the Central Florida video above.

Last Saturday I saw thousands of tree swallows flying in tight formation at West Dennis Beach.  Though sunset was two hours away they flew low across the salt marsh, hovered and touched down on bushes, swirled up and around and away.

At the height of their swirling I took some photos but couldn't capture their magic.  However, this picture shows why they flew so fast and so close.  There's a falcon in the upper right corner with a swallow in its talons.  Perhaps it's a merlin.  I would never have noticed without this photo.

Thousands of tree swallows and one falcon with prey, West Dennis Beach, MA, 1 Oct 2017 (photo by Kate St.John)
Thousands of tree swallows and one falcon with prey, West Dennis Beach, MA, 1 Oct 2017 (photo by Kate St.John)

Here's an audio description of the tree swallows' fall migration at Connecticut salt marshes at Living On Earth: BirdNote®: Roosting Tree Swallows

It's worth an autumn visit to the East Coast to see this.

 

(video by Cindy Bryant on Vimeo, photo by Kate St. John)

Caterpillars As Transformers

Woolly bear caterpillar, Pyrrharctia isabella (photo from Wikimedia)
Woolly bear caterpillar, Pyrrharctia isabella (photo from Wikimedia)

On Throw Back Thursday:

More amazing than a Transformer toy that changes from a robot into a spaceship, this woolly bear caterpillar will wrap himself in a cocoon and spend the winter transforming into a moth.

So will this hickory tussock caterpillar ...

Hickory Tussock Moth (photo by Kate St. John)
Hickory Tussock Moth (photo by Kate St. John)

... and this Promethea caterpillar.

Caterpillar of the Promethea moth, twig held by Ramona Sahni (photo by Kate St. John)
Caterpillar of the Promethea moth, twig held by Ramona Sahni (photo by Kate St. John)

Odd and ugly caterpillars become beautiful -- or boring -- moths.

Who becomes what?

Chuck Tague's 2010 guide to caterpillars and moths has the answer in photographs.  See A Game of Cat and Moth: caterpillars and what they become.

 

(photo credits: wooly bear caterpillar by Christopher Jones from Wikimedia; click on the photo to see the original. hickory tussock moth caterpillar by Kate St. John. promethea moth caterpillar by Kate St. John)

 

The Route He Takes Is Life Or Death

Common cuckoo in flight (photo from Wikimedia Commons)
Common cuckoo in flight (photo from Wikimedia Commons)

When a migratory bird population is declining, what's the cause?  Is it poor breeding success? Perils during migration? Decline on the wintering grounds?  Or all of the above?

For common cuckoos in the U.K. there's a surprising answer. Though equally successful on their breeding and wintering grounds the birds have two fall migration routes, one more dangerous than the other.  The population that takes the deadly route is declining.

Researchers attached tiny transmitters to 42 male common cuckoos (Cuculus canorus) across the U.K. and tracked them on migration from 2011 to 2014.  All of the birds spend the winter in Central Africa but they choose two routes during fall migration.  The eastern route goes east over Europe then south over Italy, the Mediterranean, and the Sahara.  The western route is a shortcut over France, Spain and the western Sahara.  Mortality was highest along the western route, especially in Spain.

Cuckoos that breed in Scotland and Wales take the long eastern route in the fall.  Cuckoos nesting in southern England split with about 60% flying east, the remainder taking the west shortcut.  Midlands and East Anglia cuckoos favor the western route.

Common cuckoos have a stable population in Scotland and Wales but a declining one in the midlands and eastern England.  When the researchers matched migration routes with population trends in the Breeding Bird Survey and Bird Atlas they found a close correlation.  Indeed, population decline in the common cuckoo is linked to their choice of migration route.

See the migration maps and read the 2016 study here at Nature Communications: Population decline is linked to migration route in the Common Cuckoo.

 

(photo of common cuckoo from Wikimedia Commons; click on the image to see the original)