A flight, a gulp, a rookery, a stunning, a swim…of Cormorants

Neotropical Cormorants by the hundreds congregated on barren islands in the middle of the lagoons at Los Pantanos de Villa reserve, south of Lima, Peru.  The various terms for groups of cormorants really don’t do this mass of breeding birds justice.  Instead of a “swim” of cormorants, it should be something like a “swarm”.

Neotropical Cormorants at Los Pantanos de Villa reserve, Lima, Peru

Neotropical Cormorants at Los Pantanos de Villa reserve, Lima, Peru.  This view shows how close the reserve is to the surrounding part of the city.

Neotropical Cormorants at Los Pantanos de Villa reserve, Lima, Peru

Neotropical Cormorant carrying nesting material to the overcrowded conglomeration of nest sites.

Neotropical Cormorants at Los Pantanos de Villa reserve, Lima, Peru

A few cormorants avoided the congestion on the islands by sunning on a nearby dead tree.

Neotropical Cormorants at Los Pantanos de Villa reserve, Lima, Peru

Cormorant  drying its wings and body feathers

Neotropical Cormorants at Los Pantanos de Villa reserve, Lima, Peru

Not the most handsome of birds…

Neotropical Cormorants at Los Pantanos de Villa reserve, Lima, Peru

Crowded conditions for nesting, but safety in numbers perhaps…

A wealth of bird life

Who would have thought you could see so many birds just 7 miles from our hotel in Miraflores and adjoining the industrial district of Chorrillos, south of Lima?

Los Pantanos de Villa ecological reserve, Lima, Peru

Franklin’s Gulls and Black Skimmers were found in huge numbers at Los Pantanos de Villa ecological reserve, on the outskirts of Lima, Peru.

Los Pantanos de Villa is a protected series of brackish marshes and lagoons designated as a RAMSAR site since 1997, meaning it is a wetlands of world-wide importance.  Both migratory and resident bird species frequent the complex of wetlands, along with a myriad of invertebrate, fish, amphibian, and mammal species.

Views of some of the wetland bird species were truly spectacular.

Black Skimmers

Black Skimmers congregated in huge numbers, but were easily flushed into flight.

Black Skimmers and Franklins Gulls, Los Pantanos de Villa reserve, Lima, Peru

Black Skimmers and Franklin’s Gulls take flight together

Black Skimmers and Franklins Gulls, Los Pantanos de Villa reserve, Lima, Peru

Unfortunately, the Skimmers weren’t interested in feeding, but glided effortlessly over the water to a different part of the beach.  When feeding they dip the longer, lower mandible into the water to scare up fish, grabbing them as they attempt to dart away.

Franklin’s Gulls and Elegant Terns, Los Pantanos de Villa

A mob of Franklin’s Gulls and Elegant Terns congregated far out in the water.  Willets foraged in shallow water in the foreground.

Black Skimmer and Elegant Tern

A Black Skimmer and Elegant Tern take off together.

An amazing, if hot and sweaty morning, of birding in the big city.

sharing the space

Sharing the space:  something we often see in nature, where species or individuals divide up the resources in a way that maximizes their gain while reducing competition from closely related individuals.  Some sparrow species seem to be flexible in where they forage, adjusting their resource use based on the presence of other birds.  For example, at the Alviso marina park in the southern San Francisco bay, we saw Song Sparrows, Field Sparrows, and White-crowned Sparrows in the same area of the park, but in quite different micro-habitats.

song sparrow in swamp grass-

This particular Song Sparrow was practicing his song, but only half-heartedly. Just a warm-up before the breeding season gets going.

Song Sparrows were found in brushy areas and dried grasses of the wetland in the park, although they can often be found on the edge of more open, grassy areas in other habitats.

white-crowned sparrow-

Juvenile and adult White-crowned Sparrows foraged in small flocks together. First-year birds have brown and white crowns; adults are a more striking black and white.

White-crowned Sparrows are migrants, overwintering in the lower 48 states but flying as far north as northern Canada and Alaska to breed in the spring.  Some birds may be permanent residents along the California coast, but these particular individuals were not acting territorial.  In the park, the White-crowned sparrows foraged at the base of shrubs and along rocks and logs on the shoreline, picking at the seeds in the litter that accumulates in crevices.  In their higher latitude or altitude breeding sites, they prefer open grassy meadows dotted with small shrubs in which they place their nests.

adult white-crowned sparrow on anise seed-

An adult White-crowned Sparrow perched on a dried wild anise plant gets a better view of where to forage next.

The third species we saw in the park, Field Sparrows, were found in the field (as their name implies), i.e., in grassy meadows dotted with occasional tall annual plants and shrubs.  These birds are typical of “old fields”, areas that are undergoing successional change from cultivation back to shrub and forest.

field sparrow-

Field Sparrows aren’t particularly colorful (except for their pale pink beak), but they sing a song that sounds like a bouncing ball, and are usually easy to spot once you’ve heard them.

These are just a few of the ground-feeding seed-eaters that most likely can be found in the park area:  Golden-crowned Sparrows and Towhees are also seen on occasion.  The variation in habitat throughout the park makes it attractive to a wide diversity of wildlife that can share the rich resources.

What’s in a name?

Some birds have names that aptly describe their physical appearance or a sound they make, or perhaps a name that derives from a descriptor in a language other than English.   The name for these distinctive black and white, long-legged wading birds in the Alviso slough make them easy to identify and remember:  Black-necked Stilt.

Black-necked Stilts

They do look like bodies perched on stilts, with their long pink legs. 

Large numbers of Black-necked Stilts congregated in the Alviso slough, probing in the mud for worms or other small invertebrates.

 Black-necked Stilts

 Black-necked Stilts

Bird lovers are keen to give large groups of one species special names, like a banditry of Chickadees, a swirl of Phalaropes, a college of cardinals, or a convocation of eagles.  What do they call a huge group of Black-necked Stilts?  Nothing quite as novel as those listed above, and in fact, disappointing that this large group of stilts is merely referred to as a “flock”.  Boring!

Like water off a duck’s back

It’s obvious where that expression, “like water off a duck’s back” came from.  Duck feathers shed water amazingly well — their plumage seems almost impenetrable.

mallard drake - feathers shedding water

Droplets of water bead up and slough (or sluff) off the outer feathers of duck plumage.  This guy had just righted himself from tipping up to scrounge algae off the rocks at the bottom of the creek bed.

No doubt part of staying warm in the chill winter temperatures and winds is staying dry, and duck plumage is intended to do just that.  Not only are the feathers incredibly dense, laid down in overlapping layers in feather tracts, but they are coated with a waxy residue from a gland at the base of the ducks tail that waterproofs them.

mallard hen

Beads of water are shed from all surfaces from head to tail end on this hen Mallard.

But what about those bare feet, exposed to near freezing water temperatures and standing on cold rocks or ice or snow for hours on end?  Feet don’t shed water, just the feathers.

mallard drake standing on ice

Cold toes?

This drake has just climbed out of the water, and is standing on ice, not something we would be comfortable doing (barefoot).  What happens when we reach for ice cubes in the freezer with wet fingers? The ice sticks to our fingers and is difficult to remove without losing some skin in the process. So how do ducks keep their wet feet from sticking to the ice?

mallard ducks-on ice

Ducks slip and slide on ice, but their feet don’t stick to the surface.

The secret is to maintain very cold toes that are the same temperature as the surface on which the duck stands or walks.  This is achieved by having arterial blood going to the foot run in parallel with the vein that is bringing cold blood back from the foot — making a heat exchange unit that promotes cooling the extremities while preserving the warmth of the body core.  Engineers have used this principle in the design of heaters and air conditioners, among many other uses.

mallard hen on ice

And this makes it nice for ducks to stand around admiring their reflections in icy pools.

running on water

Watching ducks and swans take off from the mostly unfrozen lakes the other day, I was impressed with how important those big, webbed feet are in keeping the birds’ bodies up near the surface of the water.  For example, a light-bodied, male Hooded Merganser “ran” on the water less than 50 feet before it was air-borne.

male hooded merganser running on water

The merganser’s feet barely touched the water surface as its rapid wingbeats lifted it into the air.

These small diving ducks weigh only 1-2 lb, so getting air-borne from the water surface is less of an impressive achievement.  However, Trumpeter Swans, the heaviest bird in North America, weigh 20-30 lb, and lifting those big bodies into the air requires the combined effort of both feet and wings.

trumpeter swans running on water

Initially, it looks like a lot of splashing without much lift taking place.

trumpeter swan running on water

Their bodies are so close to the water on take-off, they can’t utilize their powerful wing down-stroke for lift, so the large surface area of the feet really is essential in pushing the bird up.

trumpeter swan running on water

Even as the bird begins to lift above the water surface, it still can’t use the down-stroke for lift;  the feet continue to propel the bird upward.

And those are some really big feet aiding the launching effort.  Swans rarely show off those big appendages that are so useful in water take-offs, as well as digging up the bottom sediment while they forage.

trumpeter swan landing-

Coming in for landing with webbed feet fully extended to brace for impact…

The birds with probably the longest required take-off pathway from water are the loons.  With relatively short wings and legs placed far to the rear, loons need two to three times the distance for take-off that ducks do, and as they take-off, they too appear to be skipping along the water surface — or even hydroplaning.

loon running on water-northof49photography.com

A Common Loon (or Northern Diver) in mid-take-off (photo by northof49photography.com)

The true masters of “running on water”, however, have to be the Western Grebes, whose courtship dance is a synchronized ballet of movement across the water, all performed without a single wingbeat, paddling with just their feet in completely upright posture.  A clip from David Attenborough’s Life of Birds shows this incredible feat the best.

Getting to know you…

“getting to know all about you” — that’s what we often see in the synchronized displays of paired birds that mate for life.  It’s more commonly seen in the spring resurgence of pre-breeding behaviors, but often, mated pairs renew their bond in the fall before migrating to warmer climates with open water.

Trumpeter Swans pairs exhibited their neck bowing and chest-to-chest-wing flap and trumpet greetings with each other on Lake Vadnais yesterday with gusto.

Trumpeter Swan courtship behavior

Neck bowing behavior, up and down, from fully extended to completely bowed, repeated several times, both while swimming in parallel and while facing each other.

trumpeter swan courtship behavior trumpeter swan courtship behavior

Because these birds often don’t breed until they are 4-6 years old, cementing their partnership early is integral to their eventual breeding success, in defending their nest territory as well as protecting their offspring, which single individuals cannot do alone.  Their synchronized neck bowing behaviors occasionally escalated to more vigorous displays of wing flapping and chest bumping (kind of remniscent of football players in the end zone after a touchdown).

trumpeter swan courtship behavior

Muted trumeting accompanied the wing flap face-off between these partners.

trumpeter swan courtship behavior

But then, one swan seemed to be trying out a couple of different partners as it first performed the neck bowing sequence with one individual and then took-off flying and pursued another individual, bowing and wing-flapping with it, and then eventually settling down to feed side by side.  I wonder if this is the equivalent of swan dating?

trumpeter swan courtship behavior

Swan in the lead with partner #1, performing the head bowing behavior as they swim

trumpeter swan courtship behavior

Suddenly the lead swan takes off, trumpeting, chasing another swan into flight. Huge webbed feet paddling against the surface of the water help these large-bodied birds get aloft.

trumpeter swan courtship behavior

trumpeter swan courtship behavior

Once landed in the same area, vigorous wing-flapping and trumpeting occurs for several seconds, following by neck bows, and finally feeding side by side.

I might have thought this was one male chasing another, except for the behavior that followed.

trumpeter swan courtship behavior trumpeter swan courtship behavior trumpeter swan courtship behavior

Just another day in the lives of the Trumpeter Swans, even if confusing to us human observers.

Just passing through

As I look back at previous years’ blog posts around this time of the year, I always find a few posts about duck migration.  And once again, right on schedule, huge rafts of Common Goldeneye and Ring-necked Ducks have taken up residence on Lake Vadnais in St. Paul, to fatten up before completing the rest of their migration south.

raft of ducks

The gigantic raft of floating ducks stretches down the center of the lake more than 100 yards.

This particular reservoir seems to be a favorite stop-over for these ducks, and they usually stay until the freezing weather causes the lake to ice up.

Ring-necked ducks

Ring-necked ducks mill around in circles, dabbling and diving.

ring-necked-duck-male

You rarely get to see why these ducks are so named — for the chestnut ring of feathers at the base of the neck.

ring-necked-ducks

Male Ring-necked ducks outnumber their females by a large margin; where do all the females go on migration?

common-goldeneye-male

Small flocks of Common Goldeneye, with their distinguishing white cheek patch and bright golden eyes float separately from the Ring-necked ducks.  Dark-headed males seem to outnumber brown-headed females 10 to 1.

Ring-necked ducks

Some small groups that break off of the long raft of ducks swim purposefully (somewhere) in V-formation.

Ring-necked ducks

And some just streak through mirror-calm water in a straight line.

canvasback duck

There’s always one that has to be different — a lone male Canvasback swam toward a distant group of Goldeneyes, but they ignored him.

Seven swans a-sleeping…

A scene from across Lake Vadnais in St. Paul called to me to get closer and try to photograph the group of Trumpeter Swans.

trumpeter swans

I haven’t seen any Trumpeter Swans up close since last winter, and here they were basking on the shore of one of the lakes that supply water to St. Paul.

So I hiked around the lake trying to figure out where on the trail they might be. However, it was bow season for deer that day, and so I couldn’t stray too far off the path into the woods.

By the time I found them, this is what I saw:  seven swans a-sleeping (well, one was alert).

trumpeter swans-2

It must have been a busy morning, and I’ve never seen them a bunch of swans so completely sacked out.

However, road noise woke a couple of them up, just for a few moments.

trumpeter swans

trumpeter swans

and then right back to napping.

I guess when you’re as big as an adult Trumpeter Swan, you don’t worry too much about photographers creeping up near by.  Even the Mallards were unperturbed.

colorful rivers

Well, not so much the color of the river per se, but it was the color along the river last week in Wisconsin and Michigan during the peak of the fall color show that was impressive.  Some examples, seen between rain showers:

wolf river, wisconsin-

Along the Wolf River on the way to Rhinelander, Wisconsin, the sumac is intensely red, and maples have turned a brilliant yellow, orange, or red.

Wolf River, Wisconsin

Places like this are where you wish you were in a canoe, drifting down a lazy part of the river, gazing at the glorious color along the shoreline.

wolf river, wisconsin-

Not a huge waterfall by Lake Superior north shore standards, but a pretty scene nonetheless.

We know that warm days and cool nights of fall stimulate plants to break down their chlorophyll, unmasking all the xanthophyll and carotene photo pigments in the leaves, and those changes in leaf metabolism produce the yellow, orange, and red colors.  I have written more about the chemistry of leaf color change earlier — (“you know it’s fall when…”).  But what accounts for the synchronous color changes of rural northern hardwood forests, compared to the more prolonged sequential color changes we see in urban landscapes?

Summit peak, Porcupine Mts, Michigan

Synchronous color change in mature beech-maple hardwood forest, Porcupine Mts., Michigan.  You don’t see sights like this in many urban areas.

Lots of factors might be responsible:  urban areas are generally warmer with a less homogeneous climate than surrounding open countryside; plants in a natural forest most likely respond to climatic changes in similar ways, whereas planted urban trees, often non-native, adapt to a mixture of environmental cues with different schedules for leaf fall.  Leaves might change color more slowly and stay on trees longer in the urban environment simply because temperature and moisture conditions there are so different from the surrounding countryside.