The Flight of the Snow Geese

 

Snow Geese (Anser caerulescens) rising with the sun
at Bosque del Apache National Wildlife Refuge, New Mexico.

One of the world's great wildlife spectacles takes place each winter along the Rio Grande in New Mexico. Over 50,000 Snow Geese (Anser caerulescens) that breed in the North American Arctic during the summer, spend the cold months on the ponds and fields along the river.  

Sunrise over the Bosque del Apache
National Wildlife Refuge, New Mexico. 

Diane and I traveled with a group of birders to New Mexico this January.  We started in Albuquerque and followed the river south.  Our group arrived at the Bosque del Apache National Wildlife Refuge in the pre-dawn glow.  As we stumbled from the van, we could hear a giant flock of geese honking on the pond before us.  As the eastern horizon lightened it revealed the gabbling geese. Before the sun was up, some signal went out and the geese took flight with a mighty roar of wings.  They circled over the water and our heads with a cacophony of calls.  Their numbers were so vast they blocked out the rising sun behind them.  The geese flew for a few minutes then returned to land on the pond.  They repeated this action several times, then after the sun was well up, they flew off to their daily feeding grounds.   

Snow Geese resting before dawn.

Snow Geese in flight.

Snow Geese are joined in the Rio Grande valley by thousands of Sandhill Cranes (Antigone canadensis) and tens of thousands of ducks.  There are also Canada Geese (Branta canadensis) mixed in and a smaller number of Ross’s Geese (Anser rossii) that look like miniature Snow Geese.

Video of Snow Geese flying at sunrise.

Snow Geese have two color forms or morphs, the white Snow Goose and the darker Blue Goose.  Both morphs have black primary feathers and a white head, but the Blue Goose has a dark gray body.  Snow Geese and Blue Geese have dark pink legs and bright pink beaks that bear a black “grin patch”.  The grin patch, or smile, is the serrated edge of both the upper and lower mandibles.  The geese use this feature to graze on the rough plant material that makes up much of their diet.  The color of Snow Geese is controlled a single gene and in New Mexico the white form predominates. 

White morph Snow Goose.

Dark morph Snow Goose (Blue Goose).

White and dark morph Snow Geese in flight. 

A Ross’s Goose is about three quarters the size of a Snow Goose with a shorter neck and a pink beak that lacks the black smile.   Ross’s Geese also come in the white and blue morphs but we did not see any of the darker form in New Mexico. 

 

A Ross's Goose (Anser rossii), left of center,
among Snow Geese. The Ross's Goose is smaller with a shorter beak 
shorter neck, and no grin patch. 

Our group made a second visit to Bosque del Apache, this time in the afternoon.  The white Snow Geese were shining on the pond and an adjacent dike.  Blue forms were mixed in and with careful observation we could pick out the smaller Ross’s Geese.  The geese were placidly feeding making their honking calls when suddenly the whole flock went silent.  Every goose, on land and water raised their heads and then geese at the edge of the pond took off.  The flight became a wave sweeping across the water toward us.  As closest geese passed over our heads we were pelted with goose poop.  Like many birds, the Snow Geese lighten their load for flight and we got spattered.  They say getting hit is good luck.  We were indeed a lucky group. 

 

White and dark forms of Snow Geese resting on a dike. 

Snow Geese in flight. 

While this spectacular flight of Snow Geese can inspire awe, there is a downside. Unlike many species of birds, Snow Geese numbers are increasing.  The last century has seen their population grow from a few hundred thousand in the early 1900s to over 5 million today.  This increase in population was driven by drainage of wetlands and the conversion of forest and prairie to agriculture.  The geese found waste grain left in the fields and their numbers boomed.  The large population of Snow Geese is an environmental problem on their breeding grounds in the high Arctic.  The geese are overgrazing the tundra and this is having a negative impact on other species that live and breed in the Arctic.  One attempt to lower the Snow Goose population is a longer hunting season and increased bag limits.  So far this has not solved the problem. The Snow Goose population problem was, of course, caused by a species that currently numbers 8 billion.

Snow Geese rising.

Despite the clouds on the ecological horizon caused by the large Snow Goose population, the wintering  geese are an amazing sight that ranks with the Monarch butterflies in Mexico and the Wildebeest migration in East Africa.   If you get a chance, go to New Mexico in winter and experience the flight of the Snow Geese.

Snow Geese overhead.

Strangler Figs

 

A Strangler Fig (Ficus aurea) strangling
a hardwood tree.
Palm Beach County, Florida.

What an ominous name, Strangler Fig.  It suggests an exploitation flick with a dark night, a creaking door, and screams.  But the real Strangler Figs (Ficus sp.) are slower and perhaps more insidious than villains in teen slasher movies. 

 

A Strangler Fig on a hardwood tree. The leaves of the 
Strangler Fig are in the upper right of the photo. 
Lantana Nature Preserve, Palm Beach County, Florida. 

Strangler Fig leaves.
Palm Beach County, Florida.

The Florida Strangler Fig, Ficus aurea, grows in south Florida, the West Indies and Central America.  Its story starts with a bird dropping a seed high in a tree.  This seed germinates and begins life as an epiphyte on the host tree, doing photosynthesis, absorbing water and scarce nutrients from the air and bark.  The Strangler Fig makes a few leaves then begins to send long roots down along the trunk of the host.  If a root contacts the ground the Strangler Fig begin can begin rapid growth.  More roots grow down and fuse eventually surrounding the trunk of the host tree, thus beginning the strangulation. 

 

A Strangler Fig showing its extensive network 
of aerial roots.  
Palm Beach County, Florida. 

Branches of the Strangler Fig grow into the canopy and where the broad leaves compete with the host for light.  The Strangler Fig roots crowd the roots of the host and deprive it of water and inorganic nutrients.  Finally, the Stranger Fig encloses the host tree.  As the host grows in diameter its vascular tissue is crushed by the surrounding wood of the fig.  This prevents transport of sugars and kills the host. 

 

Strangler fig leaves.  This is an early stage
of growth on a Cabbage Palm (Sabal palmetto).
Green Cay Wetlands, Palm Beach County, Florida. 

Not all host trees are at equal risk.  Cabbage Palms (Sabal palmetto) are a commonly host of Strangler Figs in Florida.  These small palms do not have secondary growth that increases their diameter and they are not crushed by the fig.  Other tree species, at least early in their interaction with the Florida Strangler Fig, have some protection from hurricane winds because they get additional support from the fig. 

Detail of a Strangler Fig on hardwood.
Lantana Nature Preserve, Palm Beach County, Florida. 

When a host tree dies, the Strangler Fig remains behind.  You can find the dead trunk of the original host still standing and occasionally the host trunk decays leaving a hollow chimney surrounded by a mature fig tree. 

 

Strangler Fig.
Lantana Nature Preserve, Palm Beach County, Florida. 

Some Strangler Fig seeds land on the ground rather than high in a tree.  These seeds germinate and develop into free-standing Strangler Figs.  These ground spouting trees still produce the extensive aerial root system and sometimes the roots cover the ground around a large trunk. 

 

A Strangler Fig grown from a seed on the soil.  
Its root system covers the ground under the tree.
Lantana Nature Preserve, Palm Beach County, Florida. 

The fruits of Strangler Figs are small and they are an important food for many animals including bats, monkeys, birds and insects.  Some of the seeds eaten by these creatures will be deposited in other trees and the cycle begins again.   

 

Fruits of Strangler Fig.
Palm Beach County, Florida.

While their name suggests these plants are a danger in their environment, they really play a vital role in the ecosystem.  In rainforests, the Florida Strangler Fig is a keystone species of the forest canopy.  They provide food for many animals and while some host trees are strangled others are saved from high winds by the support of the fig.  If you are in the woods of south Florida or the American tropics look for stranglers, but don’t fear the fig. 

Crowned Heads - Part 2

 

A  male Northern Cardinal (Cardinalis cardinalis).
This bird's crest is laying down, showing he is relaxed.
Mecklenburg County, North Carolina.

Crests and crowns.  Birds use them to attract mates, scare off rivals and maybe just to look good.  Northern Cardinals (Cardinalis cardinalis) and their desert dwelling relatives, Pyrrhuloxias (Cardinalis sinulatus) have impressive crests.  Northern Cardinals are named for the Cardinals of the Catholic Church, whose robes are bright red.  Only the male Northern Cardinal is red, the female is brown with some red in her crest, wings and tail.   Both sexes have impressive crests they can raise and lower as the situation demands.  

A female Northern Cardinal bathing in a stream.
Her crest is raised as she enjoys the water.
Salineno Wildlife Preserve, Starr County, Texas.

Pyrrhuloxias are found in the southwest, from Texas to Arizona and south into Mexico.  Female and male Pyrrhuloxias are both gray but males are distinguished by a red face, breast and crest.  Male and female Pyrrhuloxias have bright yellow beaks and their crests are longer and thinner that those of Northern Cardinals. 

 

A female Pyrrhuloxia (Cardinalis sinulatus).
Portal, Arizona.

A male Pyrruloxia.
Portal, Arizona.

Pileated Woodpeckers (Dryocopus pileatus) are large, loud and have impressive red crests.  In fact, the name pileated refers to its crest, the pileum.  

 

A Pileated Woodpecker (Dryocopus pileatus)
with its brilliant red crest. 
Palm Beach County, Florida. 

Many Tyrant Flycatchers (Family Tyrannidae) have a prominent crest.  Eastern Phoebes (Sayornis phoebe) are small, gray flycatchers with a crest.  They live in  eastern North America and are often found near water.  They sally forth from exposed perches and pick insects from the air.  Great-crested Flycatchers (Myiarchus crinitus) are another species of eastern flycatcher with rich brown wings, a gray head and yellow belly.  Despite their name, flycatchers prefer to eat beetles, butterflies and bees.  This family also includes several species of kingbirds who are natural crown wearers.  Kingbirds have a crest topped by a crown of red feathers that are seen when the bird is agitated.  

Eastern Phoebe (Sayornis phoebe).
Mecklenburg County, North Carolina. 

Great-crested Flycatcher (Myiarchus crinitus).
Catawba College Ecological Preserve,
Rowan County, North Carolina.

Couch's Kingbird (Tyrannus couchii). 
Aransas National Wildlife Refuge, Texas.  

Titmice (genus Baeolophus) are small, gray, North American songbirds.  There are five species of titmice and they are all crested.  In the east we have the Tufted Titmouse (Baeolophus bicolor).  The Black-crested Titmouse (Baeolophus atricristatus) is found from southern Oklahoma, down through Texas and into Mexico.  This bird is very similar to the Tufted Titmouse except for the black crest.  In fact, they were considered the same species until 2002. I think the most impressive member of the genus is the Bridled Titmouse (Baeolophus wollweberi).   It is found in the deserts and mountains of southern Arizona, New Mexico and Old Mexico.  The Bridled Titmouse is typical of the genus from the neck down, but its head has jaunty black and white stripes that extend up its peaked crest. 

 

Tufted Titmouse (Baeolohus bicolor).
Rowan County, North Carolina. 

Black-crested Titmouse (Baeolophus atricristatus).
Salineno Wildlife Refuge, Starr County, Texas. 

Bridled Titmouse (Baeolophus wollweberi).
Patagonia Lake State Park, Arizona. 

Two species of waxwings are found in North America.  Cedar Waxwings (Bombycilla cedrorum) breed in southern Canada and the northern United States.  They winter in much of the United States and south to Central America.  These beautiful birds look very smooth, as if they were a carving.  Cedar Waxwings are brown and gray with a black mask and yellow tips on the tail feathers. Adult Cedar Waxwings have a red waxy spot on the wing feathers.  Cedar Waxwings have a crest that often lays flat on the head.  The diet of Cedar Waxwings is mostly fruit, but they also eat the small, fleshy cones of junipers and cedars. 

 

Cedar Waxwing (Bombycilla cedrorum)
showing its crest and red wax spots on the wings. 
Catawba College Ecological Preserve,
Rowan County, North Carolina. 

The Bohemian Waxwing (Bombycilla garrulus) is the northern counterpart of the Cedar Waxwing.  They are slightly larger than Cedar Waxwings with a similar color patten, but the Bohemian Waxwings have reddish-brown under the tail and on the face.   

 

Bohemian Waxwing (Bombycilla garrulus) eating
European Mountain Ash (Sorbus aucuparia). 
Lake County, Minnesota. 

Two Cedar Waxwings and a Bohemian Waxwing in a Christmas card pose.
Lake County, Minnesota. 

Golden-crowned Sparrows (Zonotrichia atricapilla) are a western species that breeds in Alaska and western Canada.  They winter down the west coast of the United States and into Baja, Mexico.  Male and female Golden-crowned Sparrows have similar plumage with brown wings and tail, gray breast, black head and, of course, that golden crown. 

 

A Golden-crowned Sparrow (Zonotrichia atricapilla) 
perched on a road sign.
Nome, Alaska. 

White-crowned Sparrows (Zonotrichia leucophrys) are close relatives of Golden-crowned Sparrows.  They breed across northern North America, the Rocky Mountains and the west coast.  These sparrows are highly migratory and winter throughout most of the United States and into Mexico. White-crowned Sparrows have a small pink beak, with black and white stripes on the head including a bold white crown.  

White-crowned Sparrow (Zonotrichia leucophrys)
Forsyth County, North Carolina.

These crowned birds impress us just by going about their daily activity, much as human royals do. So when you are out and about, watch for crests and crowns.  

Crowned Heads - Part 1

 

A male Ruby-crowned Kinglet (Corthylio calendula)
displaying its red crown. 
Rowan County, North Carolina. 

The crown has been a symbol of royalty for thousands of years.   This distinctive piece of headgear denotes power and authority.  Not incidentally a crown makes the wearer appear taller, contributing to the aura of superiority.  But the crown is also an anatomical term indicating the top of an animal's head. Quite a few birds have impressive crowns and some even bear a crown in their name.  We will explore some of these crowned birds in this and the next blog. 

A female Ruby-crowned Kinglet without a red crown.
Mecklenburg County, North Carolina. 

We have two species of kinglets in the southern United States, the Ruby-crowned Kinglet and the Golden-crowned Kinglet.  These tiny birds breed in coniferous woodlands from Alaska to Maine and down the Rocky Mountains.  In winter they move south and are regular visitors to our area.  Kinglets combine both royalty and a crown in their names.  The name kinglet comes from their fearless defense of nests and their mobbing of predators much larger than themselves.  Ruby-crowned Kinglets (Corthylio calendula) are olive-gray with white wing bars and a white eye ring.  The males have red feathers on top of their heads, the ruby crown, but this is only visible when the bird is upset.   

 

A Golden-crowned Kinglet (Regulus satrapa) with yellow crown.
Rowan County, North Carolina. 

The name of Golden-crowned Kinglets (Regulus satrapa) has even more royal references.  The genus, Regulus comes from the Latin root rex, meaning king.  The species name, satrapa, is derived from ancient Persian and denotes a governor of a province.  Golden-crowned Kinglets are similar in size, shape and color to Ruby-crowned Kinglets.  The key differences are Golden-crowned Kinglets have an eye line rather than an eye ring and a golden stripe on the top of the head. 

 

A Double-crested Cormorant (Nannopterum auritum)
with traces of the crests.
Green Cay Wetlands, Palm Beach County, Florida.

Lots birds have crests on their crowns.  Double-crested Cormorants (Nannopterum auritum) are large dark birds found around fresh and salt water where they catch fish.  In the breeding season they sport two plumes on their heads, the double crests.  Both male and female Double-crested Cormorants have crests and these undoubtedly make them attractive to the opposite sex.  These crests are often hard to see but one morning in Florida we ran across a Double-crested Cormorant with small crests on its head.  

A Blue Jay (Cyanocitta cristata) showing its crest.
Huntington Beach State Park, South Carolina.

Blue Jays (Cyanocitta cristata) are common birds throughout eastern North America.  They are known for their bright colors, raucous calls and a prominent crests.  The crest is so emblematic, the specific name for the Blue Jay, cristata, means crested.  A Blue Jay’s crown feathers are longer than other head feathers and the bird can raise and lower the crest.  When a Blue Jay is calm the crest lays down on the head.  But when agitated, as when it sees a predator, the Blue Jay raises its crest making the bird appear larger and more formidable.

 

A Yellow-crowned Nightheron (Nyctanassa violacea)
with its yellow crown and plume.
Rowan County, North Carolina.

Yellow-crowned and Black-crowned Nightherons are named for colors of their crowns.  Both these short-necked herons rest during the day but become active at night.  Nightherons have large red eyes, the better to see with while hunting in the dark. The Yellow-crowned Nightheron (Nyctanassa violacea) has a gray body and wings, a black head with a white cheek patch and a pale-yellow crown.  During the breeding season both males and females have long yellow plumes trailing from the top of the head.  

A Black-crowned Nightheron (Nycticorax nyctiocorax)  resting during the day.
Huntington Beach State Park, South Carolina.

The Black-crowned Nightheron (Nycticorax nycticorax) has a gray body, black wings and a black crown.  Nightherons are ambush predators, patiently sitting at the waters edge and striking out to capture fish and other small aquatic creatures. 

A Tricolored Heron (Egretta tricolor)
with a bright white plume on its crown.
Green Cay Wetlands, Palm Beach County, Florida. 

Several other species of herons and egrets, including the Tricolored Heron (Egretta tricolor), have a plume on the crown during the breeding season.  This elegant decoration complements the bird's gray body, white belly and sharp beak.

An Amazon Royal Flycatcher (Onychorhynchus coranatus)
showing its spectacular crown.  This bird was captured as
part of a bird banding project in the Amazon.
Tambopata National Preserve, Peru.
Photo courtesy of Strummer Edwards. 

The most spectacular crown I know is owned by the Royal Flycatchers in the genus Onychorhynchus.  Four species of Royal Flycatchers range from southern Mexico to Peru and Brazil.  My friend Strummer Edwards was in Peru last summer doing bird research and captured an Amazon Royal Flycatcher (Onychorhynchus coronatus) that showed off its royal crown. 

 

Video of  an Amazon Royal Flycatcher.

Tambopata National Preserve, Peru

Courtesy of Strummer Edwards.

Crests and crowns are widespread in the avian world.  They are used to attract mates, defend territories and intimidate predators.  We continue looking at these crowned birds in the next blog.

Boogie-woogie Aphids

 

Beech Blight Aphids (Grylloprociphilus imbricator) 
on American Beech (Fagus grandifolia)
Rowan County, North Carolina.

A friend contacted us about a white growth on a beech tree that wiggled when disturbed.  After a visit to view this phenomenon, some photos, videos and research, we figured out this was a group of small insects called Beech Blight Aphids (Grylloprociphilus imbricator).  These aphids were on a single branch of an American Beech tree (Fagus grandifolia).  Another common name for these odd insects is Boogie-woogie Aphids.  Unless you listen to the Andrews Sister you probably don't get a whole lot of boogie-woogie in your life. But we got a good dose with these aptly named Boogie-woogie Aphids. 

 

A single branch of American Beech with hundreds 
of Beech Blight Aphids.
Rowan County, North Carolina. 

Beech Blight Aphids.
Rowan County, North Carolina. 

Beech Blight Aphids have a dark body covered with long, white, waxy filaments.  If attacked, the predator gets a mouth full of wax and the aphid gets away.  The aphids cluster on twigs and leaves of American Beech where they feed on the tree sap.  When aphids feed, they insert their piercing mouthparts into the phloem cells in the vascular tissue of the tree.  Phloem transports organic molecules, particularly amino acids and sugars throughout the tree.  To accomplish this movement of molecules the phloem is under pressure.  When an aphid pierces a phloem cell the insect does not have to suck up the sap.  The pressure in the phloem forces the nutrients into the digestive system of the aphid.  Beech Blight Aphids absorb some of the phloem molecules but the pressure forces much of the material out the anus of the insect.  This rich exudate is called honeydew and is food for ants and nutrients for sooty mold.

 

Video of Beech Blight Aphids aka Boogie-woogie Aphids. 

 Rowan County, North Carolina.

When threatened, the massed aphids point their filament-covered abdomens into the air and wave them back and forth.   These are the boogie-woogie moves that gave Beech Blight Aphids the funny name.  This behavior is thought to provide protection from predators.  

Beech Blight Aphids.
Rowan County, North Carolina. 

Despite their large numbers, Beech Blight Aphids seem to cause little harm to the beech trees they inhabit.  So if you run across these aphids, don’t worry about beech trees and enjoy the show.